Page 68 of 68 FirstFirst ... 1858666768
Results 671 to 672 of 672

Thread: New DNA Papers

  1. #671
    Senior Member
    Posts
    4,222

    Genetic signature of natural selection in first Americans
    Amorim et al.
    http://www.pnas.org/content/early/20...41114.abstract
    "When humans moved from Asia toward the Americas over 18,000 y ago and eventually peopled the New World they encountered a new environment with extreme climate conditions and distinct dietary resources. These environmental and dietary pressures may have led to instances of genetic adaptation with the potential to influence the phenotypic variation in extant Native American populations. An example of such an event is the evolution of the fatty acid desaturases (FADS) genes, which have been claimed to harbor signals of positive selection in Inuit populations due to adaptation to the cold Greenland Arctic climate and to a protein-rich diet. Because there was evidence of intercontinental variation in this genetic region, with indications of positive selection for its variants, we decided to compare the Inuit findings with other Native American data. Here, we use several lines of evidence to show that the signal of FADS-positive selection is not restricted to the Arctic but instead is broadly observed throughout the Americas. The shared signature of selection among populations living in such a diverse range of environments is likely due to a single and strong instance of local adaptation that took place in the common ancestral population before their entrance into the New World. These first Americans peopled the whole continent and spread this adaptive variant across a diverse set of environments."

  2. The Following 11 Users Say Thank You to parasar For This Useful Post:

     Dewsloth (02-17-2017), Grossvater (02-19-2017), Judith (02-17-2017), Megalophias (02-17-2017), Menchaca (02-18-2017), palamede (02-17-2017), RCO (02-17-2017), redifflal (02-19-2017), Saetro (02-19-2017), Táltos (02-18-2017), xKeleix (02-18-2017)

  3. #672
    Senior Member
    Posts
    107
    Sex
    Location
    Canada
    Ethnicity
    Italian
    Y-DNA
    J-Y15222
    mtDNA
    U5a2b

    Italy Italy Sicily Italy Two Sicilies Vatican Star of David
    I don't know if anyone posted it yet but there's a new paper on Haplogroup Q

    https://bmcevolbiol.biomedcentral.co...862-016-0870-2

    Phylogeography of human Y-chromosome haplogroup Q3-L275 from an academic/citizen science collaboration

    Abstract

    Background
    The Y-chromosome haplogroup Q has three major branches: Q1, Q2, and Q3. Q1 is found in both Asia and the Americas where it accounts for about 90% of indigenous Native American Y-chromosomes; Q2 is found in North and Central Asia; but little is known about the third branch, Q3, also named Q1b-L275. Here, we combined the efforts of population geneticists and genetic genealogists to use the potential of full Y-chromosome sequencing for reconstructing haplogroup Q3 phylogeography and suggest possible linkages to events in population history.

    Results
    We analyzed 47 fully sequenced Y-chromosomes and reconstructed the haplogroup Q3 phylogenetic tree in detail. Haplogroup Q3-L275, derived from the oldest known split within Eurasian/American haplogroup Q, most likely occurred in West or Central Asia in the Upper Paleolithic period. During the Mesolithic and Neolithic epochs, Q3 remained a minor component of the West Asian Y-chromosome pool and gave rise to five branches (Q3a to Q3e), which spread across West, Central and parts of South Asia. Around 3–4 millennia ago (Bronze Age), the Q3a branch underwent a rapid expansion, splitting into seven branches, some of which entered Europe. One of these branches, Q3a1, was acquired by a population ancestral to Ashkenazi Jews and grew within this population during the 1st millennium AD, reaching up to 5% in present day Ashkenazi.

    Conclusions
    This study dataset was generated by a massive Y-chromosome genotyping effort in the genetic genealogy community, and phylogeographic patterns were revealed by a collaboration of population geneticists and genetic genealogists. This positive experience of collaboration between academic and citizen science provides a model for further joint projects. Merging data and skills of academic and citizen science promises to combine, respectively, quality and quantity, generalization and specialization, and achieve a well-balanced and careful interpretation of the paternal-side history of human populations.

  4. The Following 2 Users Say Thank You to Principe For This Useful Post:

     Grossvater (02-21-2017), kingjohn (02-20-2017)

Page 68 of 68 FirstFirst ... 1858666768

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •