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Thread: Did haplogroup I only develop after the Ice Age?

  1. #101
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    Quote Originally Posted by Megalophias View Post
    If all modern I is from Northwestern Europe over the last 6000 years or so, what the heck Y haplogroups did people in the rest of Europe have? And what happened to them?
    DNA seems to evidence that most lineages completely died out. Current lineages largely descend from a few individuals who managed to survive bottlenecks. My guess is that the y-DNAs of other European populations were now-extinct forms of I or IJ or K or DE, or possibly LT or A. There's no point in speculating unless there is some indicative evidence that is consistent with other reliable evidence.

    Your ancient I DNA is a good summary. The Bichon sample is clearly the most useful, and is consistent with estimates from modern DNA based on yfull and FTDNA data - indicating early presence North West of the Alps. Genetiker's call of pre-I2a1a2a1 (i.e. I2a1a2a*) seems consistent with modern DNA, as this is one of the earliest predicted I2 subclades, although I don't know the basis for this conclusion.

    Quote Originally Posted by Megalophias View Post
    Unfortunately there is no ancient Y DNA from southern Europe proper and only one Paleolithic sample.
    Unless this evidence or any indicative modern DNA evidence emerges, I would exclude it from consideration.

  2. #102
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    Quote Originally Posted by epp View Post
    DNA seems to evidence that most lineages completely died out. Current lineages largely descend from a few individuals who managed to survive bottlenecks. My guess is that the y-DNAs of other European populations were now-extinct forms of I or IJ or K or DE, or possibly LT or A. There's no point in speculating unless there is some indicative evidence that is consistent with other reliable evidence.
    Suppose that a few northern European lineages survived by founder effects while the southern ones went completely extinct, as you suggest. Scenario 1: I-M170 originated from pre-I in the north, and later some lineages expanded southward; all southern lineages (which might include pre-I/IJ* cousins of I) went extinct. Scenario 2: I-M170 originated from pre-I in the south, descendants populated the north, later some lineages of northern I re-expanded southward; all southern lineages (which would include various pre-I1 and I2*) went extinct.

    The only direct evidence that would distinguish between these scenarios is what the southern lineages were. But if there are neither surviving southern lineages nor ancient DNA from there, then there is no way to directly distinguish them. You cannot argue from present-day diversity that the origin should be in the north, because *all* original southern diversity has been erased. Nor can you appeal to parsimony, because obviously there *were* many men in the southern parts of Europe and they *did* expand northward after the LGM.

    So, even granting that all surviving I comes from recent northern expansions (certainly a good deal does), I see no reason to lower the TMRCA of I to fit a post-glacial date.

    Genetiker's call of pre-I2a1a2a1 (i.e. I2a1a2a*) seems consistent with modern DNA, as this is one of the earliest predicted I2 subclades, although I don't know the basis for this conclusion.
    He checks the DNA files made public by the study authors for a large number of equivalent SNPs. There are a small number of false positives and negatives but for good quality genomes the results are very consistent. He publishes all the Y SNP calls on his blog, you can just Google for it. (Be warned he is kind of crazy but his SNP calls are fine.)

  3. #103
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    Quote Originally Posted by Megalophias View Post
    Suppose that a few northern European lineages survived by founder effects while the southern ones went completely extinct, as you suggest. Scenario 1: I-M170 originated from pre-I in the north, and later some lineages expanded southward; all southern lineages (which might include pre-I/IJ* cousins of I) went extinct. Scenario 2: I-M170 originated from pre-I in the south, descendants populated the north, later some lineages of northern I re-expanded southward; all southern lineages (which would include various pre-I1 and I2*) went extinct.

    The only direct evidence that would distinguish between these scenarios is what the southern lineages were. But if there are neither surviving southern lineages nor ancient DNA from there, then there is no way to directly distinguish them. You cannot argue from present-day diversity that the origin should be in the north, because *all* original southern diversity has been erased. Nor can you appeal to parsimony, because obviously there *were* many men in the southern parts of Europe and they *did* expand northward after the LGM.

    So, even granting that all surviving I comes from recent northern expansions (certainly a good deal does), I see no reason to lower the TMRCA of I to fit a post-glacial date.
    I agree that the TMRCA of I could well be pre-LGM, although my interest here is not in I per se, but surviving I (which the modern DNA evidence appears to indicate is North West European post-glacial). Scenario 2 is the essentially the same as scenario 1, apart from the fact that it looks back to an earlier point. If I were to look back further than I do, the indications for the closest surviving relative of surviving I would be, in my view, the Middle East (from where J appeared to arise), rather than Cantabria. There appears no evidence to suggest that I itself either arose or didn't arise in Cantabria (apart from the fact that Spain is not located directly between the Middle East and North West Europe), so it does not come into my equation.

    Quote Originally Posted by Megalophias View Post
    He checks the DNA files made public by the study authors for a large number of equivalent SNPs. There are a small number of false positives and negatives but for good quality genomes the results are very consistent. He publishes all the Y SNP calls on his blog, you can just Google for it. (Be warned he is kind of crazy but his SNP calls are fine.)
    My read of these calls is that Bichon is probably I2a1*, rather than pre-I2a1a2a1*, which would set it back much earlier in I's development and put it into the earliest populated subclade yet discovered in haplogroup I. As the second earliest such sample is I2a1b* from Luxembourg, these represent further indication of the earliest surviving I lineages developing in and around the Rhine basin, presumably in the post-LGM era.
    By the way, I note that Genetiker seem to be of the view that the Cantabrian refuge was populated by R1b, rather than I, and that North West European I's ancestor was Balkan.

  4. #104
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    Epp
    Which ftdna group do you manage; and which dataset are your analyses based on ?
    (which subclades, which countries )
    Last edited by Gravetto-Danubian; 01-30-2016 at 11:54 PM.

  5. #105
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    Quote Originally Posted by Megalophias View Post
    Scenario 1: I-M170 originated from pre-I in the north, and later some lineages expanded southward; all southern lineages (which might include pre-I/IJ* cousins of I) went extinct. Scenario 2: I-M170 originated from pre-I in the south, descendants populated the north, later some lineages of northern I re-expanded southward; all southern lineages (which would include various pre-I1 and I2*) went extinct.

    The only direct evidence that would distinguish between these scenarios is what the southern lineages were.
    I suppose the only indication tipping it in favour of scenario 1 is that it is a less convoluted route - a two-stage general migration - a move of one section of IJ from the South East (where it shared most recent ancestry with J), followed by a move of one subclade of this section I2a1a1 to Iberia. Whereas scenario 2 would have required a four-stage migration - a move from the South East into the heart of Europe, followed by a move South West to Iberia, followed by a move back past the Alps, followed by a move of one subclade back to Iberia again (possible, but I would say less likely/plausible).

  6. #106
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    My read of these calls is that Bichon is probably I2a1*, rather than pre-I2a1a2a1*, which would set it back much earlier in I's development and put it into the earliest populated subclade yet discovered in haplogroup I.
    How do you come to that conclusion? He no negative calls for P37 or CTS595 equivalent SNPs and has about 35/70 positive calls for L1287 equivalent SNPs. There is no way that number of calls can be false positives, either it's pre-L1287 or the whole thing is completely spurious.

    Quote Originally Posted by epp View Post
    I suppose the only indication tipping it in favour of scenario 1 is that it is a less convoluted route - a two-stage general migration - a move of one section of IJ from the South East (where it shared most recent ancestry with J), followed by a move of one subclade of this section I2a1a1 to Iberia. Whereas scenario 2 would have required a four-stage migration - a move from the South East into the heart of Europe, followed by a move South West to Iberia, followed by a move back past the Alps, followed by a move of one subclade back to Iberia again (possible, but I would say less likely/plausible).
    But people did move into Europe from the SE, at least once and likely several times. They did spread into SW Europe, at least once as the Aurignacian; after that the Gravettian technocomplex moved into the SW, which at least required human contact if not major migration, and there is evidence of people moving into the SW during the height of the LGM as well. Then after the coldest period people did spread out from the SW again (and from the SE too for that matter). This is quite minimalist, people moved long distances hunting over large areas and there were all sorts of changes in material culture which might be associated with the movement of people.

    We don't need to invent migrations to fit the theory, we already have plenty of migrations. And in your version the same migrations still occurred, the only difference is when and where the ancestor of I lived. So there is nothing to be gained by invoking the principle of least moves. We can only speculate, really.

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  8. #107
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    Yes it will be very good when we get some more ancient Sample's from the paleaolithic.
    At the moment we can only make inferential hypotheses, some of which are a little half- baked.
    Last edited by Gravetto-Danubian; 01-31-2016 at 08:21 PM.

  9. #108
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    Quote Originally Posted by Megalophias View Post
    How do you come to that conclusion? He no negative calls for P37 or CTS595 equivalent SNPs and has about 35/70 positive calls for L1287 equivalent SNPs. There is no way that number of calls can be false positives, either it's pre-L1287 or the whole thing is completely spurious.
    I came to the conclusion he was probably I2a1, precisely because he does not have a negative call for I2a1 P37. He has no negative calls for CTS595, because he has no calls for CTS595 at all (either positive or negative). And he has a negative call for L1287, so does not appear to be I2a1a2a1, although does appear to be positive for its subclade I2a1a2a1a A417! Of course, as you say, the whole thing could be completely spurious.

    Given this data, I am curious why the researcher himself would have only claimed I2a per se to be his "best guess" - and wasn't even convinced enough to call it a "conservative guess". Does anyone have a link to exactly where the researcher published all this data that Genetiker has used?

    Quote Originally Posted by Megalophias View Post
    But people did move into Europe from the SE, at least once and likely several times. They did spread into SW Europe, at least once as the Aurignacian; after that the Gravettian technocomplex moved into the SW, which at least required human contact if not major migration, and there is evidence of people moving into the SW during the height of the LGM as well. Then after the coldest period people did spread out from the SW again (and from the SE too for that matter). This is quite minimalist, people moved long distances hunting over large areas and there were all sorts of changes in material culture which might be associated with the movement of people.

    We don't need to invent migrations to fit the theory, we already have plenty of migrations. And in your version the same migrations still occurred, the only difference is when and where the ancestor of I lived. So there is nothing to be gained by invoking the principle of least moves. We can only speculate, really.
    You're probably right, although they were not necessarily the same people and their descendants who made all these moves, and if they were, they were not necessarily haplogroup I. There is evidence, for instance, to indicate that haplogroup K moved massive distances, but that haplogroup I was relatively static.

    Even according to yfull estimates, which FTDNA data suggests might be substantially overstating TMRCAs, neither I1 nor I2 had arisen by the time of the last glacial maximum. So if people did move into Southern refuges at the LGM, only one of these people at most would have been a bearer of a surviving haplogroup I lineage. The question is - if this person did move that early (and not later, as indicated by FTDNA data) did he move South East or South West? As we're talking about one person, it could not have been both. So what is the most likely answer? Based on an average of yfull and FTDNA data analysis, I would estimate the likelihood is that he moved later - and as this would then have been at a time of continental warming, in the opposite direction. From which direction? I would say most likely South East, as that is the area where the descendants of his closest relatives are found.

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