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  • #31
    Thousands of horsemen may have swept into Bronze Age Europe, transforming the local population

    http://www.sciencemag.org/news/2017/...et_cid=1178069

    Call it an ancient thousand man march. Early Bronze Age men from the vast grasslands of the Eurasian steppe swept into Europe on horseback about 5000 years ago—and may have left most women behind. This mostly male migration may have persisted for several generations, sending men into the arms of European women who interbred with them, and leaving a lasting impact on the genomes of living Europeans.

    “It looks like males migrating in war, with horses and wagons,” says lead author and population geneticist Mattias Jakobsson of Uppsala University in Sweden.

    Europeans are the descendants of at least three major migrations of prehistoric people. First, a group of hunter-gatherers arrived in Europe about 37,000 years ago. Then, farmers began migrating from Anatolia (a region including present-day Turkey) into Europe 9000 years ago, but they initially didn’t intermingle much with the local hunter-gatherers because they brought their own families with them. Finally, 5000 to 4800 years ago, nomadic herders known as the Yamnaya swept into Europe. They were an early Bronze Age culture that came from the grasslands, or steppes, of modern-day Russia and Ukraine, bringing with them metallurgy and animal herding skills and, possibly, Proto-Indo-European, the mysterious ancestral tongue from which all of today’s 400 Indo-European languages spring. They immediately interbred with local Europeans, who were descendants of both the farmers and hunter-gatherers. Within a few hundred years, the Yamnaya contributed to at least half of central Europeans’ genetic ancestry.

    To find out why this migration of Yamnaya had such a big impact on European ancestry, researchers turned to genetic data from earlier studies of archaeological samples. They analyzed differences in DNA inherited by 20 ancient Europeans who lived just after the migration of Anatolian farmers (6000 to 4500 years ago) and 16 who lived just after the influx of Yamnaya (3000 to 1000 years ago). The team zeroed in on differences in the ratio of DNA inherited on their X chromosomes compared with the 22 chromosomes that do not determine sex, the so-called autosomes. This ratio can reveal the proportion of men and women in an ancestral population, because women carry two X chromosomes, whereas men have only one.

    Europeans who were alive from before the Yamnaya migration inherited equal amounts of DNA from Anatolian farmers on their X chromosome and their autosomes, the team reports today in the Proceedings of the National Academy of Sciences. This means roughly equal numbers of men and women took part in the migration of Anatolian farmers into Europe.

    But when the researchers looked at the DNA later Europeans inherited from the Yamnaya, they found that Bronze Age Europeans had far less Yamnaya DNA on their X than on their other chromosomes. Using a statistical method developed by graduate student Amy Goldberg in the lab of population geneticist Noah Rosenberg at Stanford University in Palo Alto, California, the team calculated that there were perhaps 10 men for every woman in the migration of Yamnaya men to Europe (with a range of five to 14 migrating men for every woman). That ratio is “extreme”—even more lopsided than the mostly male wave of Spanish conquistadores who came by ship to the Americas in the late 1500s, Goldberg says.

    Such a skewed ratio raises red flags for some researchers, who warn it is notoriously difficult to estimate the ratio of men to women accurately in ancient populations. But if confirmed, one explanation is that the Yamnaya men were warriors who swept into Europe on horses or drove horse-drawn wagons; horses had been recently domesticated in the steppe and the wheel was a recent invention. They may have been “more focused on warfare, with faster dispersal because of technological inventions” says population geneticist Rasmus Nielsen of the University of California, Berkeley, who is not part of the study.

    But warfare isn’t the only explanation. The Yamnaya men could have been more attractive mates than European farmers because they had horses and new technologies, such as copper hammers that gave them an advantage, Goldberg says.

    The finding that Yamnaya men migrated for many generations also suggests that all was not right back home in the steppe. “It would imply a continuing strongly negative push factor within the steppes, such as chronic epidemics or diseases,” says archaeologist David Anthony of Hartwick College in Oneonta, New York, who was not an author of the new study. Or, he says it could be the beginning of cultures that sent out bands of men to establish new politically aligned colonies in distant lands, as in later groups of Romans or Vikings.
    The Yamnaya men could have been more attractive mates than European farmers because they had horses and new technologies, such as copper hammers that gave them an advantage,
    It's interesting to note that it's not just recent generations that can be won over by the offer of a bit of bling.



    When did humans settle down? The house mouse may have the answer
    http://www.sciencemag.org/news/2017/...et_cid=1240257

    Sometime about 10,000 years ago, the earliest farmers put down their roots—literally and figuratively. Agriculture opened the door to (theoretically) stable food supplies, and it let hunter-gatherers build permanent dwellings that eventually morphed into complex societies in many parts of the world. But how that transition played out is a contentiously debated topic. Now, a new study shows that our path to domesticity zig-zagged between periods of sedentary life and a roaming hunter-gatherer lifestyle. The evidence? The presence—and absence—of the common house mouse.

    “It’s remarkable, using a lowly house mouse to monitor a major milestone in human history,” says Melinda Zeder, curator of Old World archaeology at the Smithsonian National Museum of Natural History in Washington, D.C., who wasn’t involved with the study. “It’s really a masterful way of monitoring sedentism.”

    To explore the transition to agriculture, scientists have looked to the Natufians, an ancient hunter-gatherer society that flourished from about 12,500 to 9500 B.C.E. in a part of the Middle East called the Levant, which includes pieces of modern-day Cyprus, Syria, Israel, Jordan, Lebanon, and Palestine. The Natufians were among the first people known to domesticate animals—dogs and hogs—and may have been the first to transition to farming. As they moved from seasonally collecting acorns and hunting gazelle to farming wheat and barley, many researchers think they went through an intermediary phase: a semisedentary period in which they built stone dwellings but still hunted for sustenance and moved on when resources became scarce. But evidence of exactly when and how humans became sedentary has been hard to come by.

    So Thomas Cucchi, an archaeologist at the University of Aberdeen in the United Kingdom, decided to turn to the creatures living alongside humans at the time, specifically house mice (Mus domesticus), which live almost exclusively in or near houses and planted fields. He teamed up with Lior Weissbrod, a fellow archaeologist at the University of Haifa in Israel, who was analyzing wild and domesticated mice living today in Kenya.
    Update 10/04/2017



    There's no such thing as a 'pure' European—or anyone else

    http://www.sciencemag.org/news/2017/...et_cid=1328086

    When the first busloads of migrants from Syria and Iraq rolled into Germany 2 years ago, some small towns were overwhelmed. The village of Sumte, population 102, had to take in 750 asylum seekers. Most villagers swung into action, in keeping with Germany’s strong Willkommenskultur, or “welcome culture.” But one self-described neo-Nazi on the district council told The New York Times that by allowing the influx, the German people faced “the destruction of our genetic heritage” and risked becoming “a gray mishmash.”

    In fact, the German people have no unique genetic heritage to protect. They—and all other Europeans—are already a mishmash, the children of repeated ancient migrations, according to scientists who study ancient human origins. New studies show that almost all indigenous Europeans descend from at least three major migrations in the past 15,000 years, including two from the Middle East. Those migrants swept across Europe, mingled with previous immigrants, and then remixed to create the peoples of today.

    Using revolutionary new methods to analyze DNA and the isotopes found in bones and teeth, scientists are exposing the tangled roots of peoples around the world, as varied as Germans, ancient Philistines, and Kashmiris. Few of us are actually the direct descendants of the ancient skeletons found in our backyards or historic homelands. Only a handful of groups today, such as Australian Aborigines, have deep bloodlines untainted by mixing with immigrants.
    The first Europeans came from Africa via the Middle East and settled there about 43,000 years ago. But some of those pioneers, such as a 40,000-year-old individual from Romania, have little connection to today’s Europeans, Reich says.

    His team studied DNA from 51 Europeans and Asians who lived 7000 to 45,000 years ago. They found that most of the DNA in living Europeans originated in three major migrations, starting with hunter-gatherers who came from the Middle East as the glaciers retreated 19,000 to 14,000 years ago. In a second migration about 9000 years ago, farmers from northwestern Anatolia, in what is now Greece and Turkey, moved in.

    That massive wave of farmers washed across the continent. Ancient DNA records their arrival in Germany, where they are linked with the Linear Pottery culture, 6900 to 7500 years ago. A 7000-year-old woman from Stuttgart, Germany, for example, has the farmers’ genetic signatures, setting her apart from eight hunter-gatherers who lived just 1000 years earlier in Luxembourg and Sweden. Among people living today, Sardinians retain the most DNA from those early farmers, whose genes suggest that they had brown eyes and dark hair.

    The farmers moved in family groups and stuck to themselves awhile before mixing with local hunter-gatherers, according to a study in 2015 that used ancient DNA to calculate the ratio of men to women in the farming groups. That’s a stark contrast to the third major migration, which began about 5000 years ago when herders swept in from the steppe north of the Black Sea in what is now Russia. Those Yamnaya pastoralists herded cattle and sheep, and some rode newly domesticated horses, says archaeologist David Anthony of Hartwick College in Oneonta, New York.

    In the journal Antiquity last month, Kristiansen and paleogeneticist Eske Willerslev at the University of Copenhagen reported that the sex ratios of the earliest Yamnaya burials in central Europe suggest that the new arrivals were mostly men. Arriving with few women, those tall strangers were apparently eager to woo or abduct the local farmers’ daughters. Not long after the Yamnaya invasion, their skeletons were buried with those of women who had lived on farms as children, according to the strontium and nitrogen isotopes in their bones, says Price, who analyzed them.

    The unions between the Yamnaya and the descendants of Anatolian farmers catalyzed the creation of the famous Corded Ware culture, known for its distinctive pottery impressed with cordlike patterns, Kristiansen says. According to DNA analysis, those people may have inherited Yamnaya genes that made them taller; they may also have had a then-rare mutation that enabled them to digest lactose in milk, which quickly spread.

    It was a winning combination. The Corded Ware people had many offspring who spread rapidly across Europe. They were among the ancestors of the Bell Beaker culture of central Europe, known by the vessels they used to drink wine, according to a study by Kristiansen and Reich published this month. “This big wave of Yamnaya migration washed all the way to the shores of Ireland,” says population geneticist Dan Bradley of Trinity College in Dublin. Bell Beaker pots and DNA appeared about 4000 years ago in burials on Rathlin Island, off the coast of Northern Ireland, his group reported this year.

    This new picture means that the Hermann of lore was himself a composite of post–ice age hunter-gatherers, Anatolian farmers, and Yamnaya herders. So are most other Europeans—including the ancient Romans whose empire Arminius fought.

    The three-part European mixture varies across the continent, with different ratios of each migration and trace amounts of other lineages. But those quirks rarely match the tales people tell about their ancestry. For example, the Basques of northern Spain, who have a distinct language, have long thought themselves a people apart. But last year, population geneticist Mattias Jakobsson of Uppsala University in Sweden reported that the DNA of modern Basques is most like that of the ancient farmers who populated northern Spain before the Yamnaya migration. In other words, Basques are part of the usual European mix, although they carry less Yamnaya DNA than other Europeans.

    Farther north, the Irish Book of Invasions, written by an anonymous author in the 11th century, recounts that the “Sons of Míl Espáine … after many wanderings in Scythia and Egypt” eventually reached Spain and Ireland, creating a modern Irish people distinct from the British—and linked to the Spanish. That telling resonates with a later yarn about ships from the Spanish Armada, wrecked on the shores of Ireland and the Scottish Orkney Islands in 1588, Bradley says: “Good-looking, dark-haired Spaniards washed ashore” and had children with Gaelic and Orkney Islands women, creating a strain of Black Irish with dark hair, eyes, and skin.

    Although it’s a great story, Bradley says, it “just didn’t happen.” In two studies, researchers have found only “a very small ancient Spanish contribution” to British and Irish DNA, says human geneticist Walter Bodmer of the University of Oxford in the United Kingdom, co-leader of a landmark 2015 study of British genetics.

    The Irish also cherish another origin story, of the Celtic roots they are said to share with the Scots and Welsh. In the Celtic Revival of the 19th and 20th centuries, writers such as William Butler Yeats drew from stories in the Book of Invasions and medieval texts. Those writings described a migration of Gaels, or groups of Celts from the mainland who clung to their identity in the face of later waves of Roman, Germanic, and Nordic peoples.

    But try as they might, researchers so far haven’t found anyone, living or dead, with a distinct Celtic genome. The ancient Celts got their name from Greeks who used “Celt” as a label for barbarian outsiders—the diverse Celtic-speaking tribes who, starting in the late Bronze Age, occupied territory from Portugal to Turkey. “It’s a hard question who the Celts are,” says population geneticist Stephan Schiffels of the Max Planck Institute for the Science of Human History in Jena, Germany.

    Bodmer’s team traced the ancestry of 2039 people whose families have lived in the same parts of Scotland, Northern Ireland, and Wales since the 19th century. These people form at least nine genetic and geographic clusters, showing that after their ancestors arrived in those regions, they put down roots and married their neighbors. But the clusters themselves are of diverse origin, with close ties to people now in Germany, Belgium, and France. “‘Celtic’ is a cultural definition,” Bodmer says. “It has nothing to do with hordes of people coming from somewhere else and replacing people.”

    English myths fare no better. The Anglo-Saxon Chronicle recounts that in 449 C.E., two Germanic tribespeople, Hengist and Horsa, sailed from what is now the Netherlands to southeast England, starting a fierce conflict. As more Angles, Saxons, and Jutes arrived, violence broke out with the local Britons and ended in “rivers of blood,” according to accounts by medieval monks. Scholars have debated just how bloody that invasion was, and whether it was a mass migration or a small delegation of elite kings and their warriors.

    An answer came in 2016 from a study of the ancient DNA of Anglo-Saxons and indigenous Britons, who were buried side by side in the fifth and sixth centuries in a cemetery near Cambridge, U.K. They lived and died together and even interbred, as shown by one person who had a mix of DNA from both Britons and Anglo-Saxons, and a genetic Briton who was buried with a large cruciform Anglo-Saxon brooch. Although the stories stress violence, the groups “were mixing very quickly,” says Duncan Sayer, an archaeologist at the University of Central Lancashire in Preston, U.K., who co-wrote the study.

    The team went on to show that 25% to 40% of the ancestry of modern Britons is Anglo-Saxon. Even people in Wales and Scotland—thought to be Celtic strongholds—get about 30% of their DNA from Anglo-Saxons, says co-author Chris Tyler-Smith of the Wellcome Trust’s Sanger Institute in Hinxton, U.K.

    Update 16/05/2017



    Migration—the choices we face....by Mohamed H. A. Hassan

    http://science.sciencemag.org/content/356/6339/667.full

    More than 1 million refugees and migrants arrived in Europe in 2015, and nearly 390,000 more in 2016, many fleeing conflict in the Middle East and North Africa. European leaders have often accommodated the migrants with admirable generosity, even while facing stiff political opposition. Yet, if developed countries focus only on immediate domestic impacts of mass migration, they will miss a critical point: When thousands of people, including many researchers, leave their home countries, the exodus perpetuates instability in those countries and damages prospects for future development.
    Before the Syrian conflict began in 2011, the country had 31,000 doctors. Today, roughly half are gone, many scattered to adjacent countries, Europe, and North America. Uncounted thousands of scientists, engineers, and advanced students from across the region have joined them. How can nations rebuild and progress when much of their scientific workforce has fled? How can they hope to raise farm output, improve public health, or prepare for natural disaster?
    This core dilemma of migration will confront leaders of the G7 developed nations when they convene 26 to 27 May. Sustained development in poor countries is essential to easing migration, but developed countries have an uneven record in making necessary investments. Today, the scale of migration is unprecedented and the needs are more urgent. Mass migration is emerging as a permanent feature of geopolitical stress and global change.
    The United Nations (UN) High Commissioner for Refugees reports that, at the end of 2015, nearly 41 million people were internally displaced, while almost 25 million were refugees or asylum-seekers. They are driven from their homes by conflict, economic insecurity, climate disruption, or a combination of these. Migration can destabilize adjacent countries, which are often economically and politically vulnerable. But political tension and xenophobia also reflect the power of migration to disrupt countries in North America, Europe, and Australia.

    Sub-Saharan Africa illustrates choices confronting policy-makers. From one perspective, it is a time of optimism: Economic growth is robust. Hunger is in retreat. Life spans are on the rise. A building boom in new universities shows that leaders understand the power of knowledge—especially science and technology—to drive growth. Still, sub-Saharan Africa remains desperately poor. Political instability is widespread. Many universities lack qualified faculty. Population will grow from 1.2 billion today to a projected 2.5 billion by 2050. If Africa cannot grow and develop fast enough to provide education and jobs for its young people, then millions may see migration as their best option.

    The UN Sustainable Development Goals were created in part to address such issues. But none of the Least Developed Countries can achieve this growth and development without partners. It is thus an acutely important moment for the G7 countries—and science is more capable than ever of providing support.

    The World Academy of Sciences, and other academies and organizations that support at-risk scientists, can offer fellowships, training, and resources so that refugee scientists can contribute to their new countries and someday help to rebuild their home countries. Social scientists can provide vital research on migration, from drivers to integration and financial impact. Science diplomacy, crucially, must help bring countries together for cooperative efforts. And building science is a focus of aid programs advanced by the European Union, and by countries such as Germany, the United Kingdom, Sweden, and Italy.

    But developed countries are not alone in this mission. Nations of the South share responsibility, and migration should be taken up more energetically by the G20 countries, including Brazil, China, India, and South Africa, which convene in July. Researchers in even the poorest countries have a direct interest in migration, and an increasing capacity to contribute to solutions.
    Update 18/05/2017
    Last edited by Jo Bowyer; 18-05-2017, 11:22 PM.
    Jo Bowyer
    Chartered Physiotherapist Registered Osteopath.
    "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

    Comment


    • #32
      Parent-offspring conflict and the evolution of infant-directed song

      Abstract
      We present a theory of the origin and evolution of infant-directed song, a form of music found in many cultures. After examining the ancestral ecology of parent-infant relations, we propose that infant-directed song arose in an evolutionary arms race between parents and infants, stemming from the dynamics of parent-offspring conflict. We describe testable predictions that follow from this theory, consider some existing evidence for them, and entertain the possibility that infant-directed song could form the basis for the development of other, more complex forms of music.
      1. Introduction
      The human music faculty has no established evolutionary basis (Fitch, 2005, Fitch, 2006a, Honing et al., 2015, McDermott and Hauser, 2005, Patel, 2008, Wallin et al., 2000). This is odd, considering evolutionists' tendency to focus their attention on human behaviors that are complex, pervasive, and difficult to explain — all characteristics of music — and their success in explaining them. For example, theories of sexual selection (Darwin, 1871, Fisher, 1915, Fisher, 1930), parental investment (Trivers, 1972), inclusive fitness (Hamilton, 1964), reciprocal altruism (Trivers, 1971), and parent-offspring conflict (Haig, 1993, Trivers, 1974) have helped to explain and predict swaths of extravagant, costly, and otherwise confusing phenomena in human behavior.

      In each of these disparate areas the same analytic strategy has been productive: diagnosis of an adaptive problem present in ancestral environments, prediction of the design features of a potential adaptation which could solve that adaptive problem, and experimentation to examine the goodness-of-fit between those predicted features and real-world behavior. Research taking this approach has revealed, for example, that human incest aversion results from an adaptation for avoiding the genetic hazards of mating with close kin, not from social learning (Lieberman, Tooby, & Cosmides, 2007). Categorizing others on the basis of race is a byproduct of an adaptation for coalition categorization, not an adaptation for race detection per se (Kurzban, Tooby, & Cosmides, 2001). Sex differences in mate preferences result from sexually differentiated adaptations for minimizing cuckoldry (in men) and divestiture (in women), not from cultural happenstance (Buss & Schmitt, 1993).

      Music is in principle no different than these non-musical behaviors in that it must be explicable either as the product of one or more adaptations or as a byproduct of one or more adaptations. A legitimate evolutionary theory of music can thus specify why a cognitive system with the properties of the human music faculty could emerge as a result of fitness-relevant goals that were reliably present in human ancestral history, and do so independently of anything already known about human music. Such an analysis requires the specification of a well-defined adaptive problem or problems and a correspondingly well-defined hypothesis for why some aspect of musical behavior is a candidate adaptation to solve that problem (or, rather, is a byproduct of some other adaptation). Together, these would yield predictions about the features music should and should not have.

      Here, we attempt such an analysis, aiming to explain the emergence of a single, specific, well-defined form of music that is found in many cultures: infant-directed song. We examine the ancestral ecology of parent-infant relations and hypothesize that infant-directed song arose in an evolutionary arms race between parents and infants, stemming from the dynamics of parent-offspring conflict. We describe a series of falsifiable hypotheses that follow from this theory, consider existing evidence for and against each, and conclude by speculating on potential links between infant-directed song and music, writ large.



      How Music and Instruments Began: A Brief Overview of the Origin and Entire Development of Music, from Its Earliest Stages

      http://journal.frontiersin.org/artic...017.00008/full

      Music must first be defined and distinguished from speech, and from animal and bird cries. We discuss the stages of hominid anatomy that permit music to be perceived and created, with the likelihood of both Homo neanderthalensis and Homo sapiens both being capable. The earlier hominid ability to emit sounds of variable pitch with some meaning shows that music at its simplest level must have predated speech. The possibilities of anthropoid motor impulse suggest that rhythm may have preceded melody, though full control of rhythm may well not have come any earlier than the perception of music above. There are four evident purposes for music: dance, ritual, entertainment personal, and communal, and above all social cohesion, again on both personal and communal levels. We then proceed to how instruments began, with a brief survey of the surviving examples from the Mousterian period onward, including the possible Neanderthal evidence and the extent to which they showed “artistic” potential in other fields. We warn that our performance on replicas of surviving instruments may bear little or no resemblance to that of the original players. We continue with how later instruments, strings, and skin-drums began and developed into instruments we know in worldwide cultures today. The sound of music is then discussed, scales and intervals, and the lack of any consistency of consonant tonality around the world. This is followed by iconographic evidence of the instruments of later antiquity into the European Middle Ages, and finally, the history of public performance, again from the possibilities of early humanity into more modern times. This paper draws the ethnomusicological perspective on the entire development of music, instruments, and performance, from the times of H. neanderthalensis and H. sapiens into those of modern musical history, and it is written with the deliberate intention of informing readers who are without special education in music, and providing necessary information for inquiries into the origin of music by cognitive scientists.
      Update 20/06/2017



      Why Does Music Make Us Feel So Much?

      http://knowingneurons.com/2017/07/12...EMAIL_CAMPAIGN)

      Many scientists have theorized that the universal nature of music must have an evolutionary origin. Charles Darwin, the naturalist best known for his contributions to the science of evolution, suggested that humans use music to attract partners, which he explained this extensively his book The descent of man, and Selection in relation to sex. Darwin believed that we “endeavoured to charm each other with musical notes and rhythm.” This idea is comparable to the sexual selection processes shaped by birdsong, a well known mate selection theory. Other scientists have suggested that ‘feeling the rhythm’ is a way of synchronizing footsteps to avoid being heard by predators.
      Update 14/07/2017
      Last edited by Jo Bowyer; 14-07-2017, 10:34 AM.
      Jo Bowyer
      Chartered Physiotherapist Registered Osteopath.
      "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

      Comment


      • #33
        Widespread signatures of positive selection in common risk alleles associated to autism spectrum disorder

        http://journals.plos.org/plosgenetic...l.pgen.1006618

        Abstract

        The human brain is the outcome of innumerable evolutionary processes; the systems genetics of psychiatric disorders could bear their signatures. On this basis, we analyzed five psychiatric disorders, attention deficit hyperactivity disorder, autism spectrum disorder (ASD), bipolar disorder, major depressive disorder, and schizophrenia (SCZ), using GWAS summary statistics from the Psychiatric Genomics Consortium. Machine learning-derived scores were used to investigate two natural-selection scenarios: complete selection (loci where a selected allele reached fixation) and incomplete selection (loci where a selected allele has not yet reached fixation). ASD GWAS results positively correlated with incomplete-selection (p = 3.53*10−4). Variants with ASD GWAS p<0.1 were shown to have a 19%-increased probability to be in the top-5% for incomplete-selection score (OR = 1.19, 95%CI = 1.11–1.8, p = 9.56*10−7). Investigating the effect directions of minor alleles, we observed an enrichment for positive associations in SNPs with ASD GWAS p<0.1 and top-5% incomplete-selection score (permutation p<10−4). Considering the set of these ASD-positive-associated variants, we observed gene-expression enrichments for brain and pituitary tissues (p = 2.3*10−5 and p = 3*10−5, respectively) and 53 gene ontology (GO) enrichments, such as nervous system development (GO:0007399, p = 7.57*10−12), synapse organization (GO:0050808, p = 8.29*10−7), and axon guidance (GO:0007411, p = 1.81*10−7). Previous genetic studies demonstrated that ASD positively correlates with childhood intelligence, college completion, and years of schooling. Accordingly, we hypothesize that certain ASD risk alleles were under positive selection during human evolution due to their involvement in neurogenesis and cognitive ability.



        Temple Grandin: The world needs all kinds of minds
        https://www.ted.com/talks/temple_gra...b792#t-1164745

        Temple Grandin thinks that we would still be sitting outside caves without autistic people. I see a lot of autistic kids and teenagers (surprise, surprise!) because I can interact with them, sometimes for pain issues, movement, gut related problems,sometimes because they are not coping in school, some are home schooled, many have behavioural issues. I have been there, a stranger in a strange land and I emphasize the fact that it is us that must learn to deal with neurotypicals because they can't see life from our perspective. The best parents can do for autistic children is to teach them formal good manners from an early age, we may not always choose to use them.

        Enjoy..........



        A pilot study to determine the feasibility of enhancing cognitive abilities in children with sensory processing dysfunction
        http://journals.plos.org/plosone/art...l.pone.0172616

        Abstract

        Children with Sensory Processing Dysfunction (SPD) experience incoming information in atypical, distracting ways. Qualitative challenges with attention have been reported in these children, but such difficulties have not been quantified using either behavioral or functional neuroimaging methods. Furthermore, the efficacy of evidence-based cognitive control interventions aimed at enhancing attention in this group has not been tested. Here we present work aimed at characterizing and enhancing attentional abilities for children with SPD. A sample of 38 SPD and 25 typically developing children were tested on behavioral, neural, and parental measures of attention before and after a 4-week iPad-based at-home cognitive remediation program. At baseline, 54% of children with SPD met or exceeded criteria on a parent report measure for inattention/hyperactivity. Significant deficits involving sustained attention, selective attention and goal management were observed only in the subset of SPD children with parent-reported inattention. This subset of children also showed reduced midline frontal theta activity, an electroencephalographic measure of attention. Following the cognitive intervention, only the SPD children with inattention/hyperactivity showed both improvements in midline frontal theta activity and on a parental report of inattention. Notably, 33% of these individuals no longer met the clinical cut-off for inattention, with the parent-reported improvements persisting for 9 months. These findings support the benefit of a targeted attention intervention for a subset of children with SPD, while simultaneously highlighting the importance of having a multifaceted assessment for individuals with neurodevelopmental conditions to optimally personalize treatment.
        Update 07/04/2017
        Last edited by Jo Bowyer; 08-04-2017, 12:43 AM.
        Jo Bowyer
        Chartered Physiotherapist Registered Osteopath.
        "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

        Comment


        • #34
          How footprints trapped in time unlocked a mystery of early hominids

          https://aeon.co/videos/how-footprint...96b58-69418129

          The British-born scientist Mary Leakey (1913-1996) was one the foremost paleoanthropologists of the 20th century. Alongside her husband Louis Leakey (1903-1972), she was responsible for several important breakthroughs in East African prehistory. Arguably her most important discovery occurred after her husband’s death when, during an excavation in Tanzania in 1976, she and her team found a set of 3.6-million-year-old early hominid footprints that had been improbably preserved by a combination of volcanic ash and rain. These footprints revealed, for the first time, the way in which our earliest bipedal ancestors walked upright.
          Jo Bowyer
          Chartered Physiotherapist Registered Osteopath.
          "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

          Comment


          • #35
            Ancient skulls may belong to elusive humans called Denisovans

            http://www.sciencemag.org/news/2017/...et_cid=1194555



            Since their discovery in 2010, the extinct ice age humans called Denisovans have been known only from bits of DNA, taken from a sliver of bone in the Denisova Cave in Siberia, Russia. Now, two partial skulls from eastern China are emerging as prime candidates for showing what these shadowy people may have looked like.

            In a paper published this week in Science, a Chinese-U.S. team presents 105,000- to 125,000-year-old fossils they call “archaic Homo.” They note that the bones could be a new type of human or an eastern variant of Neandertals. But although the team avoids the word, “everyone else would wonder whether these might be Denisovans,” which are close cousins to Neandertals, says paleo*anthropologist Chris Stringer of the Natural History Museum in London.
            Back in December 2007, archaeologist Zhan-Yang Li of the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing was wrapping up his field season in the town of Lingjing, near the city of Xuchang in the Henan province in China (about 4000 kilometers from the Denisova Cave), when he spotted some beautiful quartz stone tools eroding out of the sediments. He extended the field season for two more days to extract them. On the very last morning, his team discovered a yellow piece of rounded skull cap protruding from the muddy floor of the pit, in the same layer where he had found the tools.
            The team went back for another six seasons and managed to find 45 more fossils that fit together into two partial crania. The skulls lack faces and jaws. But they include enough undistorted pieces for the team to note a close resemblance to Neandertals. One cranium has a huge brain volume of 1800 cubic centimeters—on the upper end for both Neandertals and moderns—plus a Neandertal-like hollow in a bone on the back of its skull. Both crania have prominent brow ridges and inner ear bones that resemble those of Neandertals but are distinct from our own species, Homo sapiens.


            Mutations may reveal how Tibetans can live on world’s highest plateau
            http://www.sciencemag.org/news/2017/...et_cid=1253428


            It’s not easy living thousands of meters above sea level. The air holds less oxygen, there’s more harmful ultraviolet (UV) radiation from the sun, and food supplies vary dramatically from season to season. But that doesn’t stop nearly 5 million people from living on the Tibetan Plateau, the world’s highest at an average of 1200 meters. Now, scientists working with the largest-ever sample of Tibetan genomes have discovered seven new ways in which Tibetan genes have been tweaked to cope with high altitude, resulting in higher body mass index (BMI) and a boost in the body’s production of the vitamin folate.

            Scientists have long known how the people of the Tibetan Plateau, including Nepal’s famous mountain-climbing Sherpa, deal with oxygen levels up to 40% less than those at sea level. Unlike most mountain climbers, whose bodies acclimatize to higher elevations by temporarily boosting hemoglobin—a blood protein that carries oxygen throughout the body—Tibetans have evolved a suite of other biochemical adaptations that let their bodies use oxygen extremely efficiently. That’s good news for the Tibetans, because too much hemoglobin makes the blood harder to pump and likelier to clot, increasing the chances of stroke and heart disease.

            But the details of Tibetans’ adaptations have been a mystery. Previous studies have suggested that two genes, EPAS1 (inherited from ancient hominins known as Denisovans) and ELGN1, play roles in reducing hemoglobin and boosting oxygen use. To find out whether other genes are involved, a team of scientists led by Jian Yang at the University of Queensland in Brisbane, Australia, and Zi-Bing Jin at Wenzhou Medical University in China compared the genomes of 3008 Tibetans and 7287 non-Tibetans.
            Update 04/04/2017



            Evolutionary history of Tibetans inferred from whole-genome sequencing

            http://journals.plos.org/plosgenetic...l.pgen.1006675

            Abstract

            The indigenous people of the Tibetan Plateau have been the subject of much recent interest because of their unique genetic adaptations to high altitude. Recent studies have demonstrated that the Tibetan EPAS1 haplotype is involved in high altitude-adaptation and originated in an archaic Denisovan-related population. We sequenced the whole-genomes of 27 Tibetans and conducted analyses to infer a detailed history of demography and natural selection of this population. We detected evidence of population structure between the ancestral Han and Tibetan subpopulations as early as 44 to 58 thousand years ago, but with high rates of gene flow until approximately 9 thousand years ago. The CMS test ranked EPAS1 and EGLN1 as the top two positive selection candidates, and in addition identified PTGIS, VDR, and KCTD12 as new candidate genes. The advantageous Tibetan EPAS1 haplotype shared many variants with the Denisovan genome, with an ancient gene tree divergence between the Tibetan and Denisovan haplotypes of about 1 million years ago. With the exception of EPAS1, we observed no evidence of positive selection on Denisovan-like haplotypes.

            Author summary

            The Tibetan population has been residing on high plateau for thousands of years and developed unique adaptation to the local environment. To investigate the demographic history of Tibetans and search for possible adaptive genetic variants, we performed whole-genome sequencing of 27 Tibetan individuals. We found evidence of genetic separation between Han and Tibetans around since 44 and 58 thousand years ago; however, these two populations maintained a high rate of gene flow until 9 thousand years ago. In addition to replicating two previously discovered candidate genes (EGLN1 and EPAS1) for high altitude adaptation, we also found three new candidate genes, including PTGIS, VDR and KCTD12. We confirmed the high similarity of EPAS1 gene region between Tibetans and Denisovans, but did not detect any evidence of high altitude adaptation from Denisovan gene alleles otherwise.
            Update 28/04/2017
            Last edited by Jo Bowyer; 28-04-2017, 01:44 PM.
            Jo Bowyer
            Chartered Physiotherapist Registered Osteopath.
            "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

            Comment


            • #36
              https://www.sciencedaily.com/release...0306154222.htm

              As bumblebees forage for nectar, at a certain point, they will move to another area once their search for food becomes too inefficient -- a behavior, also observed among other animals, which conforms to the 'marginal value theorem.' In like manner, groups of modern hunter-gatherers do the same according to a study. The study 'provides insight on how our hominin ancestors might have moved as groups across ancient landscapes.'
              The Batek are a socially egalitarian society who formerly lived nomadically in the tropical rainforests of north-central Peninsular Malaysia. Based on data from a 1975-1976 study by cultural anthropologists Kirk and Karen Endicott, Dartmouth researchers analyzed the relocation patterns of Batek living in the Upper Lebir River watershed for 93 days as they sequentially occupied 11 residential camps, staying for an average of 8.2 days at each camp. Men generally hunted small game and women gathered wild yams and fruit. In addition, the men also collected rattan (climbing palm) vines and traded it for rice.

              To test the predictions of the marginal value theorem, the researchers measured how much food the Batek acquired over time in camps, and predicted when the Batek should move based on how quickly they depleted local resources. A close match was found between the predictions of the marginal value model and the actual camp relocation times. They typically relocated to another camp before completely depleting local resources. Even though the Batek lived in complex social groups, they managed to maximize their foraging efficiency as a group, perhaps, due in part to their extensive social cooperation and food sharing. Camp movement decisions were discussed and made collectively.

              Although the Batek often said that their decisions to move were based on women's foraging for carbohydrates (often tubers), the data revealed otherwise, as rattan turned out to be a more accurate predictor of how long the Batek stayed at a camp.



              Brain Evolved to Need Exercise

              http://neurosciencenews.com/evolutio...exercise-6982/

              In a new article published in the journal Trends in Neurosciences, University of Arizona researchers suggest that the link between exercise and the brain is a product of our evolutionary history and our past as hunter-gatherers.

              UA anthropologist David Raichlen and UA psychologist Gene Alexander, who together run a research program on exercise and the brain, propose an “adaptive capacity model” for understanding, from an evolutionary neuroscience perspective, how physical activity impacts brain structure and function.

              Their argument: As humans transitioned from a relatively sedentary apelike existence to a more physically demanding hunter-gatherer lifestyle, starting around 2 million years ago, we began to engage in complex foraging tasks that were simultaneously physically and mentally demanding, and that may explain how physical activity and the brain came to be so connected.

              “We think our physiology evolved to respond to those increases in physical activity levels, and those physiological adaptations go from your bones and your muscles, apparently all the way to your brain,” said Raichlen, an associate professor in the UA School of Anthropology in the College of Social and Behavioral Sciences.

              “It’s very odd to think that moving your body should affect your brain in this way — that exercise should have some beneficial impact on brain structure and function — but if you start thinking about it from an evolutionary perspective, you can start to piece together why that system would adaptively respond to exercise challenges and stresses,” he said.

              Having this underlying understanding of the exercise-brain connection could help researchers come up with ways to enhance the benefits of exercise even further, and to develop effective interventions for age-related cognitive decline or even neurodegenerative diseases such as Alzheimer’s.

              Notably, the parts of the brain most taxed during a complex activity such as foraging — areas that play a key role in memory and executive functions such as problem solving and planning — are the same areas that seem to benefit from exercise in studies.

              “Foraging is an incredibly complex cognitive behavior,” Raichlen said. “You’re moving on a landscape, you’re using memory not only to know where to go but also to navigate your way back, you’re paying attention to your surroundings. You’re multitasking the entire time because you’re making decisions while you’re paying attention to the environment, while you are also monitoring your motor systems over complex terrain. Putting all that together creates a very complex multitasking effort.”
              Update 27/06/2017
              Last edited by Jo Bowyer; 27-06-2017, 03:41 AM.
              Jo Bowyer
              Chartered Physiotherapist Registered Osteopath.
              "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

              Comment


              • #37
                Neandertals ate woolly rhinos and mushrooms, may have used painkillers and antibiotics By Sid Perkins Mar. 8, 2017

                http://www.sciencemag.org/news/2017/...et_cid=1205342

                The new findings are “very exciting, a whole new layer of evidence that Neandertals’ diets were varied,” says Amanda Henry, a paleoanthropologist at Leiden University in the Netherlands, who was not involved in the work. “Neandertals weren’t just consuming things for calories or for taste,” she says, but instead may have been taking advantage of the medicinal properties of certain plants and bacterial foodstuffs.



                Neandertals and modern humans started mating early

                http://www.sciencemag.org/news/2017/...et_cid=1421397

                For almost a century, Neandertals were considered the ancestors of modern humans. But in a new plot twist in the unfolding mystery of how Neandertals were related to modern humans, it now seems that members of our lineage were among the ancestors of Neandertals. Researchers sequenced ancient DNA from the mitochondria—tiny energy factories inside cells—from a Neandertal who lived about 100,000 years ago in southwest Germany. They found that this DNA, which is inherited only from the mother, resembled that of early modern humans.
                After comparing the mitochondrial DNA (mtDNA) with that of other archaic and modern humans, the researchers reached a startling conclusion: A female member of the lineage that gave rise to Homo sapiens in Africa mated with a Neandertal male more than 220,000 years ago—much earlier than other known encounters between the two groups. Her children spread her genetic legacy through the Neandertal lineage, and in time her African mtDNA completely replaced the ancestral Neandertal mtDNA.

                Other researchers are enthusiastic about the hypothesis, described in Nature Communications this week, but caution that it will take more than one genome to prove. “It’s a nice story that solves a cool mystery—how did Neandertals end up with mtDNA more like that of modern humans,” says population geneticist Ilan Gronau of the Interdisciplinary Center Herzliya in Israel. But “they have not nailed it yet.”

                The study adds to a catalog of ancient genomes, including mtDNA as well as the much larger nuclear genomes, from more than a dozen Neandertals. Most of these lived at the end of the species’ time on Earth, about 40,000 to 50,000 years ago. Researchers also have analyzed the complete nuclear and mtDNA genomes of another archaic group from Siberia, called the Denisovans. The nuclear DNA suggested that Neandertals and Denisovans were each other’s closest kin and that their lineage split from ours more than 600,000 years ago.
                Update 05/07/2017
                Last edited by Jo Bowyer; 05-07-2017, 01:29 PM.
                Jo Bowyer
                Chartered Physiotherapist Registered Osteopath.
                "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                Comment


                • #38
                  Neurocomputational Consequences of Evolutionary Connectivity Changes in Perisylvian Language Cortex

                  http://www.jneurosci.org/content/37/11/3045?etoc=

                  Abstract

                  The human brain sets itself apart from that of its primate relatives by specific neuroanatomical features, especially the strong linkage of left perisylvian language areas (frontal and temporal cortex) by way of the arcuate fasciculus (AF). AF connectivity has been shown to correlate with verbal working memory—a specifically human trait providing the foundation for language abilities—but a mechanistic explanation of any related causal link between anatomical structure and cognitive function is still missing. Here, we provide a possible explanation and link, by using neurocomputational simulations in neuroanatomically structured models of the perisylvian language cortex. We compare networks mimicking key features of cortical connectivity in monkeys and humans, specifically the presence of relatively stronger higher-order “jumping links” between nonadjacent perisylvian cortical areas in the latter, and demonstrate that the emergence of working memory for syllables and word forms is a functional consequence of this structural evolutionary change. We also show that a mere increase of learning time is not sufficient, but that this specific structural feature, which entails higher connectivity degree of relevant areas and shorter sensorimotor path length, is crucial. These results offer a better understanding of specifically human anatomical features underlying the language faculty and their evolutionary selection advantage.

                  SIGNIFICANCE STATEMENT Why do humans have superior language abilities compared to primates? Recently, a uniquely human neuroanatomical feature has been demonstrated in the strength of the arcuate fasciculus (AF), a fiber pathway interlinking the left-hemispheric language areas. Although AF anatomy has been related to linguistic skills, an explanation of how this fiber bundle may support language abilities is still missing. We use neuroanatomically structured computational models to investigate the consequences of evolutionary changes in language area connectivity and demonstrate that the human-specific higher connectivity degree and comparatively shorter sensorimotor path length implicated by the AF entail emergence of verbal working memory, a prerequisite for language learning. These results offer a better understanding of specifically human anatomical features for language and their evolutionary selection advantage.



                  Language, Paleoneurology, and the Fronto-Parietal System

                  http://journal.frontiersin.org/artic...017.00349/full
                  Last edited by Jo Bowyer; 03-07-2017, 04:27 PM.
                  Jo Bowyer
                  Chartered Physiotherapist Registered Osteopath.
                  "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                  Comment


                  • #39
                    Modern humans were in Southeast Asia 20,000 years earlier than thought, ancient teeth reveal

                    http://www.sciencemag.org/news/2017/...et_cid=1484280

                    Previous studies suggested that after evolving in Africa, modern humans eventually made their way to Southeast Asia, but researchers have argued whether they arrived about 50,000 years ago or earlier. Recent studies put modern humans in Australia by about 65,000 years ago, but there has been little direct evidence of an early presence in Southeast Asia.
                    Jo Bowyer
                    Chartered Physiotherapist Registered Osteopath.
                    "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                    Comment


                    • #40
                      On the trail of ancient mariners


                      http://science.sciencemag.org/content/357/6351/542.full

                      Most archaeologists think the first Americans arrived by boat. Now, they're beginning to prove it
                      Jo Bowyer
                      Chartered Physiotherapist Registered Osteopath.
                      "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                      Comment


                      • #41
                        Evolution has improved upon the genetic foundations of human health for millennia. But could that have recently gone in reverse?

                        http://neurosciencenews.com/genetics-evolution-7359/

                        Despite what may be a striking, recent negative trend, through the millennia genetic risks to health clearly appear to have diminished, according to the study’s main finding. “That was to be expected because larger populations are better able to purge disease-causing genetic variants,” Lachance said.

                        The researchers scoured DNA records covering thousands of years of human remains along with those of our distant evolutionary cousins, such as Neanderthals, for genetic locations, or “loci,” associated with common diseases. “We looked at heart disease, digestive problems, dental health, muscle disorders, psychiatric issues, and some other traits,” Cooper said.

                        After determining that they could computationally compare 3,180 disease loci common to ancients and modern humans, the researchers checked for genetic variants, or “alleles,” associated with the likelihood of those diseases, or associated with the protection from them. Nine millennia ago and before that, the genetic underpinnings of the diseases looked dismal.

                        “Humans way back then, and Neanderthals and Denisovans — they’re our distant evolutionary cousins — they appear to have had a lot more alleles that promoted disease than we do,” Lachance said. “The genetic risks for cardiovascular disease were particularly troubling in the past.”

                        Crumbling health genetics?

                        As millennia marched on, overall genetic health foundations got much better, the study’s results showed. The frequency of alleles that promote disease dropped while protective alleles rose at a steady clip.

                        Then again, there’s that nagging initial impression in the study’s data that, for a few centuries now, things may have gone off track. “Our genetic risk was on a downward trend, but in the last 500 or 1,000 years, our lifestyles and environments changed,” Lachance said.

                        This is speculation, but perhaps better food, shelter, clothing, and medicine have made humans less susceptible to disease alleles, so having them in our DNA is no longer as likely to kill us before we reproduce and pass them on.

                        A grain of data salt

                        Also, the betterment over millennia in genetic health underpinnings seen in the analysis of select genes from 147 ancestors stands out so clearly that the researchers have had to wonder if the reversal in pattern in recent centuries, which seems so inconsistent with that long-term trend, is not perhaps a coincidence in the initial data set. The scientists would like to analyze more data sets to feel more confident about the apparent reversal.

                        “We’d like to see more studies done on samples taken from humans who lived from 400 years ago to now,” Cooper said.

                        They would also like to do more research on the positioning of the genetic health of ancients relative to modern humans. “We may be overestimating the genetic health of previous hominins (humans and evolutionary cousins including Neanderthals),” Lachance said, “and we may need to shift estimates of hereditary disease risks for them over, which would mean they all had a lot worse health than we currently think.”
                        Jo Bowyer
                        Chartered Physiotherapist Registered Osteopath.
                        "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                        Comment


                        • #42
                          The earliest settlers of Mesoamerica date back to the late Pleistocene

                          http://journals.plos.org/plosone/art...l.pone.0183345

                          Jo Bowyer
                          Chartered Physiotherapist Registered Osteopath.
                          "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                          Comment


                          • #43
                            Neandertals and early modern humans probably didn’t meet at rumored rendezvous site

                            http://www.sciencemag.org/news/2017/...et_cid=1529159

                            Shared genes between modern humans and Neandertals make it clear that at some time and place in the past, the two species did meet and interbreed—just not at Vindija Cave, Devièse says. “DNA studies have demonstrated that anatomically modern humans and Neandertals interbred,” he says. “There is no question about this … although the two groups for the most part were not living side-by-side, it would seem. With this dating work, we are continuing our work to understand where and for how long the two species coexisted.”
                            Jo Bowyer
                            Chartered Physiotherapist Registered Osteopath.
                            "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                            Comment


                            • #44
                              Humans still evolving, large-scale study of genetic data shows

                              Researchers find a drop in some harmful genetic mutations in longer-lived people

                              https://www.sciencedaily.com/release...0905145553.htm



                              In a study analyzing the genomes of 210,000 people in the United States and Britain, researchers at Columbia University find that the genetic variants linked to Alzheimer's disease and heavy smoking are less frequent in people with longer lifespans, suggesting that natural selection is weeding out these unfavorable variants in both populations.

                              Researchers further find that sets of genetic mutations that predispose people to heart disease, high cholesterol, obesity, and asthma, also appear less often in people who lived longer and whose genes are therefore more likely to be passed down and spread through the population. The results are published in the Sept. 5 issue of PLOS Biology.

                              "It's a subtle signal, but we find genetic evidence that natural selection is happening in modern human populations," said study coauthor Joseph Pickrell, an evolutionary geneticist at Columbia and New York Genome Center.

                              New favorable traits evolve when genetic mutations arise that offer a survival edge. As the survivors of each generation pass on those beneficial mutations, the mutations and their adaptive traits become more common in the general population. Though it may take millions of years for complex traits to evolve, say allowing humans to walk on two legs, evolution itself happens with each generation as adaptive mutations become more frequent in the population.

                              The genomic revolution has allowed biologists to see the natural selection process in action by making the genetic blueprint of hundreds of thousands of people available for comparison. By tracking the relative rise and fall of specific mutations across generations of people, researchers can infer which traits are spreading or dwindling.

                              The researchers analyzed the genomes of 60,000 people of European ancestry genotyped by Kaiser Permanente in California, and 150,000 people in Britain genotyped through the U.K. Biobank. To compensate for the relative lack of old people in the Biobank, the researchers used the participants' parents age at death as a proxy as they looked for the influence of specific mutations on survival.

                              Two population-level mutation shifts stood out. In women over 70, researchers saw a drop in the frequency of the ApoE4 gene linked to Alzheimer's, consistent with earlier research showing that women with one or two copies of the gene tend to die well before those without it. Researchers saw a similar drop, starting in middle age, in the frequency of a mutation in the CHRNA3 gene associated with heavy smoking in men.

                              The researchers were surprised to find just two common mutations across the entire human genome that heavily influence survival. The high power of their analysis should have detected other variants had they existed, they said. This suggests that selection has purged similar variants from the population, even those that act later in life like the ApoE4 and CHRNA3 genes.

                              "It may be that men who don't carry these harmful mutations can have more children, or that men and women who live longer can help with their grandchildren, improving their chance of survival," said study coauthor Molly Przeworski, an evolutionary biologist at Columbia.
                              Jo Bowyer
                              Chartered Physiotherapist Registered Osteopath.
                              "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

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                              • #45
                                Neandertals, like humans, may have had long childhoods

                                http://www.sciencemag.org/news/2017/...et_cid=1558749

                                Neandertals have long been seen as the James Deans of human evolution—they grew up fast, died young, and became legends. But now, a rare skeleton of a Neandertal child suggests that our closest cousins didn’t all lead such fast lives—and that our own long childhoods aren’t unique. The find may reveal how Neandertals, like humans, had enough energy to grow bigger brains.

                                “We like the paper because it puts the idea of ‘Neanderthal exceptionalism’ to rest,” wrote anthropologist Marcia Ponce de León and neurobiologist Christoph Zollikofer from the University of Zurich in Switzerland (who are not authors of the new study) in an email. “RIP.”

                                Researchers have long known that modern humans take almost twice as long as chimpanzees to reach adulthood and have wondered when and why our ancestors evolved the ability to prolong childhood and delay reproduction. Our distant ancestors, such as the famous fossil Lucy and other australopithecines, matured quickly and died young like chimps. Even early members of our own genus Homo, such as the 1.6-million-year-old skeleton of an H. erectus boy, grew up faster than we do.

                                But by the time the earliest known members of our species, H. sapiens, were alive 300,000 years ago at Jebel Irhoud in Morocco, they were taking longer to grow up. A leading theory is that big brains are so metabolically expensive that humans have to delay the age of reproduction—and, hence, have longer childhoods—so first-time mothers are older and, thus, bigger and strong enough to have the energy to feed babies with such big brains after birth when their brains are doubling in size.

                                Earlier studies found that Neandertal permanent teeth grew significantly faster and erupted earlier than those of our own species. This suggested that we reach adulthood a few years later than Neandertals, and that our developmental schedule is unique. But a recent study of the skulls of 15 Neandertals by Ponce de León and Zollikofer found that different parts of the brain developed after birth in a pattern similar to modern humans, which suggested Neandertals also had longer childhoods.
                                Jo Bowyer
                                Chartered Physiotherapist Registered Osteopath.
                                "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

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