The human microbiome: Me, myself, us

[Jo Bowyer]

Global divergence of the human follicle mite Demodex folliculorum: Persistent associations between host ancestry and mite lineages

http://www.pnas.org/content/early/2015/12/09/1512609112

Abstract

Microscopic mites of the genus Demodex live within the hair follicles of mammals and are ubiquitous symbionts of humans, but little molecular work has been done to understand their genetic diversity or transmission. Here we sampled mite DNA from 70 human hosts of diverse geographic ancestries and analyzed 241 sequences from the mitochondrial genome of the species Demodex folliculorum. Phylogenetic analyses recovered multiple deep lineages including a globally distributed lineage common among hosts of European ancestry and three lineages that primarily include hosts of Asian, African, and Latin American ancestry. To a great extent, the ancestral geography of hosts predicted the lineages of mites found on them; 27% of the total molecular variance segregated according to the regional ancestries of hosts. We found that D. folliculorum populations are stable on an individual over the course of years and that some Asian and African American hosts maintain specific mite lineages over the course of years or generations outside their geographic region of birth or ancestry. D. folliculorum haplotypes were much more likely to be shared within families and between spouses than between unrelated individuals, indicating that transmission requires close contact. Dating analyses indicated that D. folliculorum origins may predate modern humans. Overall, D. folliculorum evolution reflects ancient human population divergences, is consistent with an out-of-Africa dispersal hypothesis, and presents an excellent model system for further understanding the history of human movement.

[Diane]

You're welcome Mark. :angel:

Hi Anita, we have a welcome forum here - please start a thread and introduce yourself. :angel:

[AnitaPOTW]

Fascinating information. Thanks!

[Mark Hollis]

Makes me think in the 'I' illusion that the 'I' in what 'I am' keeps getting smaller.

Parts i will mull over
- 'an organ, namely that it is an organised system of cells' - recognising that there is more than a 'location-istic' anatomy (We're not treating muscles, we're treating movement systems)
- 'Another intervention, though, allows entire bacterial ecosystems to be transferred from one gut to another. This is the transplanting of a small amount of faeces.' - Brilliant. Just think what social taboos and stigmatizations that person had to cognitively traverse prior to arriving at that solution. What an ingenious solution.

Thanks^1,000,000 Diane

[Diane]

The human microbiome: Me, myself, us

Looking at human beings as ecosystems that contain many collaborating and competing species could change the practice of medicine

Much, much fodder for thought.
:thumbs_up:thumbs_up:thumbs_up