Page 1 of 5 123 ... LastLast
Results 1 to 10 of 47

Thread: Hunter-gatherer skin colour

  1. #1
    Registered Users
    Posts
    891
    Sex
    Y-DNA (P)
    O1b2a1a2a1-CTS723
    mtDNA (M)
    D5a2a1b*

    Hunter-gatherer skin colour

    Quote Originally Posted by Bernard View Post
    Felix M. Key et al., 2016, Nature Communications: Human adaptation and population differentiation in the light of ancient genomes
    Adaptive alleles—especially those associated with pigmentation—are mostly of hunter-gatherer origin, although lactose persistence arose in a haplotype present in farmers.
    So hunter gatherers had light skin? I thought WHG had dark skin?
    And ENF were responsible for LP? I thought they were lactose intolerant and that pastoral dairy farmers adapted to LP much later?

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

     Agamemnon (03-19-2016),  parasar (03-19-2016)

  3. #2
    Gold Class Member
    Posts
    2,718
    Sex

    Quote Originally Posted by Hando View Post
    So hunter gatherers had light skin? I thought WHG had dark skin?
    And ENF were responsible for LP? I thought they were lactose intolerant and that pastoral dairy farmers adapted to LP much later?
    As far as I can tell, the article is extremely misleading, for two reasons:

    1) The article imagines that Loschbour (WHG) and Stuttgart (ENF) completely represent the modern European gene pool. They pretend that no steppic introgression ever occurred, so of course they do not even consider attributing any DNA shift to it.

    2) The article claims that an allele originated in a particular group if its background occurs in that group, even if the allele itself never did. The article does not consider the possibility that the same background may have been present elsewhere (e.g., the steppe) as well.

  4. The Following 11 Users Say Thank You to lgmayka For This Useful Post:

     Awale (03-21-2016),  Dubhthach (03-19-2016),  Hando (03-20-2016),  jdean (03-19-2016),  Jean M (03-19-2016),  King (03-20-2016),  Krefter (03-19-2016),  KSDA (03-20-2016),  parasar (03-19-2016),  Pribislav (05-11-2016),  Tomenable (03-20-2016)

  5. #3
    Registered Users
    Posts
    2,449
    Sex

    Quote Originally Posted by Hando View Post
    So hunter gatherers had light skin? I thought WHG had dark skin?
    This is what the articles says about pigmentation -

    The derived allele upstream of OCA2 (rs12913832 in HERC2) is associated with blue iris colour in Europeans42 and light skin pigmentation43; both this variant and its linked variation show that Loschbour carried the predominant European haplotype (Fig. 6a). The derived allele in SLC45A2 non-synonymous rs16891982 is associated with lighter skin pigmentation and increased melanoma risk in Europeans44, 45. No ancestral genome carries rs16891982’s derived allele, but Loschbour carries the haplotype that, in present-day populations, is linked to the derived allele (Fig. 6b). Therefore hunter-gatherer populations likely contributed both OCA2 and SLC45A2 advantageous alleles to the European gene pool. This agrees well with these populations inhabiting northern European areas before the arrival of southern farmer groups. Lighter skin pigmentation has been proposed to be advantageous in northern latitudes to sustain vitamin D3 production in low-ultraviolet environments46
    Quote Originally Posted by Hando View Post
    And ENF were responsible for LP? I thought they were lactose intolerant and that pastoral dairy farmers adapted to LP much later?
    This is what the article says about LP -

    It is known that the two derived alleles associated with LP in Europe (in rs4988235 and rs182549)53 are absent in the two ancient genomes33 and are not observed in Europe until ~2300 BC in an individual of inferred steppe ancestry17. But the European tail includes a large number of alleles in the lactase enhancer region and the LP haplotype (chr2:135859371-136740900) that are exclusively present in Stuttgart (65% of Stuttgart specific targets; Fig. 6c). Thus the haplotype that is today associated with LP in Europe originated most likely in this genetic background, which we detect only in the Stuttgart farmer, although this individual itself did not carry the LP allele.
    So what they are saying is that a group of alleles can be used to deduce if one of those traits likely appeared in a certain group or not. Since they mention LP in an individual of steppe ancestry we know they did take steppic introgression into consideration.

  6. The Following 2 Users Say Thank You to ArmandoR1b For This Useful Post:

     Hando (03-20-2016),  Tomenable (03-28-2016)

  7. #4
    Registered Users
    Posts
    1,620
    Sex
    Location
    Calgary
    Ethnicity
    Anglo
    Nationality
    Canadian
    Y-DNA (P)
    I2-S2361 < L801
    mtDNA (M)
    H2a2b(1)
    mtDNA (P)
    H3

    Canada
    Quote Originally Posted by lgmayka View Post
    As far as I can tell, the article is extremely misleading, for two reasons:

    1) The article imagines that Loschbour (WHG) and Stuttgart (ENF) completely represent the modern European gene pool. They pretend that no steppic introgression ever occurred, so of course they do not even consider attributing any DNA shift to it.

    2) The article claims that an allele originated in a particular group if its background occurs in that group, even if the allele itself never did. The article does not consider the possibility that the same background may have been present elsewhere (e.g., the steppe) as well.
    The paper was published by the same department that did the "Massive migration from the steppe" paper. Qiaomei Fu is a co-author on the "Massive migration from the steppe" paper. They mention steppe ancestry. They cite the "Massive migration from the steppe" paper and explain why they didn't use the genomes from it. Should they include an explicit disclaimer that one hunter-gatherer genome and one farmer genome do not encapsulate the whole genetic history of Europe?

    Usually when writing a scientific paper one assumes that the target audience is familiar with the literature - and there are references for anyone who isn't - and is capable of basic critical thinking.

    I find it bizarre that someone (i.e. you) who is familiar with the literature and is capable of critical thinking can somehow get the impression that such papers are clumsily attempting to mislead you.

    Now, does the same haplotype background occur in steppe people? Good question, but outside the scope of this paper. Maybe someone who has the steppe genomes could check.
    Last edited by Megalophias; 03-19-2016 at 05:56 PM.

  8. The Following 6 Users Say Thank You to Megalophias For This Useful Post:

     Agamemnon (03-19-2016),  ArmandoR1b (03-19-2016),  Awale (03-21-2016),  Gravetto-Danubian (03-20-2016),  Saetro (03-20-2016),  Tomenable (03-28-2016)

  9. #5
    Gold Class Member
    Posts
    2,718
    Sex

    Quote Originally Posted by Megalophias View Post
    They cite the "Massive migration from the steppe" paper and explain why they didn't use the genomes from it.
    But they don't explain why they are asserting conclusions that are rash/misleading without such genomes. Most of the paper is written as if steppe ancestry doesn't exist or is irrelevant.
    ---
    Adaptive alleles—especially those associated with pigmentation—are mostly of hunter-gatherer origin...
    ...
    We also show that these alleles were mostly contributed by ancient hunter gatherers, who resided in Europe thousands of years before the arrival of southern farmer groups.
    ...
    Simulations using a more complex demographic scenario in Europe, with several ancient groups including early hunter gatherers, farmers and Basal Eurasians...
    ...
    ...Europeans display ancestry from both populations in their genomes.
    ...
    Therefore hunter-gatherer populations likely contributed both OCA2 and SLC45A2 advantageous alleles to the European gene pool.
    ...
    European hunter gatherers contributed disproportionally to these putatively selected alleles, which are enriched in genes associated with variation in pigmentation.

    ---
    All these assertions, and more, have been written on the assumption that European DNA is composed almost entirely of WHG and ENF.
    Quote Originally Posted by Megalophias View Post
    Should they include an explicit disclaimer that one hunter-gatherer genome and one farmer genome do not encapsulate the whole genetic history of Europe?
    Yes, but more than that: They need to rewrite their conclusions.
    Quote Originally Posted by Megalophias View Post
    I find it bizarre that someone (i.e. you) who is familiar with the literature and is capable of critical thinking can somehow get the impression that such papers are clumsily attempting to mislead you.
    If you don't like the term misleading, you can substitute the word rash. In either case, the point is that they are jumping to conclusions based on two datapoints which--as you correctly pointed out--they know very well are insufficient to describe European DNA composition.

  10. The Following 7 Users Say Thank You to lgmayka For This Useful Post:

     Awale (03-21-2016),  Hando (03-20-2016),  jdean (03-20-2016),  King (03-20-2016),  Megalophias (03-20-2016),  Saetro (03-20-2016),  Tomenable (03-28-2016)

  11. #6
    Suspended Account
    Posts
    4,753
    Sex

    They probably have good reasons for being somewhat dismissive of the role of steppe populations in this context. My guess is it's because they have a bunch of UP and Mesolithic genomes from all over Eurasia now, and have come to the conclusion that Ust'-Ishim, Loschbour and Stuttgart are enough, at least for the time being and in this context.

    In other words, Loschbour isn't all that different from MA1 or the EHG samples, while Stuttgart isn't all that different from Kotias. And what they differ in can probably be explained by contributions from different lines leading from Ust'-Ishim or his close relatives.

  12. The Following 6 Users Say Thank You to Generalissimo For This Useful Post:

     Agamemnon (03-20-2016),  Awale (03-21-2016),  Hando (03-20-2016),  Helgenes50 (03-20-2016),  jdean (03-20-2016),  Tomenable (03-28-2016)

  13. #7
    Registered Users
    Posts
    1,140
    Sex
    Location
    Brisbane
    Nationality
    Australian
    Y-DNA (P)
    T-P322 (T1a2b1)
    mtDNA (M)
    H6a1

    Australia Cornwall England Scotland Germany Poland
    Quote Originally Posted by Generalissimo View Post
    They probably have good reasons for being somewhat dismissive of the role of steppe populations in this context.
    Yes, but it is unusual for a paper to be accepted for publication in which those reasons are not spelled out.
    Then again, Nature Communications exists to let the world know about an idea quickly, without a long peer-review process.
    One important result of this method of release is to get those interested talking about the idea involved.
    That has certainly succeeded!

  14. The Following 5 Users Say Thank You to Saetro For This Useful Post:

     Awale (03-21-2016),  Hando (03-20-2016),  King (03-20-2016),  lgmayka (03-20-2016),  Megalophias (03-20-2016)

  15. #8
    Registered Users
    Posts
    1,620
    Sex
    Location
    Calgary
    Ethnicity
    Anglo
    Nationality
    Canadian
    Y-DNA (P)
    I2-S2361 < L801
    mtDNA (M)
    H2a2b(1)
    mtDNA (P)
    H3

    Canada
    Quote Originally Posted by lgmayka View Post
    But they don't explain why they are asserting conclusions that are rash/misleading without such genomes. Most of the paper is written as if steppe ancestry doesn't exist or is irrelevant.
    I certainly agree with you that the paper would have benefited from a few sentences explaining the role of steppe admixture, rather than just rolling it all into hunter-gatherers + farmers.

  16. The Following 2 Users Say Thank You to Megalophias For This Useful Post:

     Awale (03-21-2016),  Hando (03-20-2016)

  17. #9
    Gold Class Member
    Posts
    2,718
    Sex

    Quote Originally Posted by Generalissimo View Post
    In other words, Loschbour isn't all that different from MA1 or the EHG samples, while Stuttgart isn't all that different from Kotias.
    Loschbour doesn't have ANE, and Stuttgart doesn't have CHG.
    Last edited by lgmayka; 03-20-2016 at 03:37 AM.

  18. The Following 3 Users Say Thank You to lgmayka For This Useful Post:

     Hando (03-20-2016),  King (03-20-2016),  parasar (03-20-2016)

  19. #10
    Suspended Account
    Posts
    4,753
    Sex

    Quote Originally Posted by lgmayka View Post
    Loschbour doesn't have ANE, and Stuttgart doesn't have CHG.
    Loschbour's relationship to MA1 and EHG is still not certain, and in fact less certain after Haak et al., in which several models are floated, one in which Loschbour has EHG admixture. And Stuttgart does have some CHG. It's one of the LBK genomes with the clearest signal of CHG, which shows up in most of the published ADMIXTURE analyses, including in Haak et al. (teal component).

    In any case, these are just models to help explain the very complex and fluid relationships between these meta populations. That's why they change from paper to paper, especially after new genomes are sequenced.

    Reich recently mentioned a project looking at Ice Age Europe, and it's likely that at least several UP/Mesolithic genomes from across Eurasia that we don't know about have already been analyzed, and both the authors of this paper and reviewers are aware of them. So I wouldn't look at this study as necessarily lacking anything, but rather perhaps hinting at things to come. This has already happened in earlier papers, so nowadays it's good to read between the lines whenever these teams from major labs float new models.

  20. The Following 6 Users Say Thank You to Generalissimo For This Useful Post:

     ArmandoR1b (03-20-2016),  ffoucart (03-21-2016),  Gravetto-Danubian (03-20-2016),  Hando (03-20-2016),  Helgenes50 (03-20-2016),  R.Rocca (03-21-2016)

Page 1 of 5 123 ... LastLast

Similar Threads

  1. Replies: 1
    Last Post: 09-07-2018, 04:14 PM
  2. Replies: 0
    Last Post: 09-07-2018, 09:57 AM
  3. Hair and skin colour in Europeans (Modern and Ancient)
    By catman44 in forum Ancient (aDNA)
    Replies: 2
    Last Post: 04-18-2018, 03:19 PM
  4. Light skin colour and where it comes from?
    By sktibo in forum Ancient (aDNA)
    Replies: 2
    Last Post: 02-23-2017, 05:11 AM
  5. Replies: 1
    Last Post: 11-24-2015, 01:08 PM

Posting Permissions

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