November 13, 2010

Sunghir ancient mtDNA: is it H17'27?

I am these days trying to update my already obsolete map series on European and Mediterranean ancient mtDNA, as I did in the past I'm using Jean Manco's site as reference. 

However many clades seem poorly described (maybe because the haplogroup knowledge has varied since the papers were published) and I'm taking my time trying to identify the confusing haplogroups when possible. 

One of the strangest cases is the two individuals from Sunghir, in Central Russia, from Gravettian times (25,000 BP). Their well preserved mtDNA has only one mutation from the Cambridge Reference Sequence (CRS), which is H2a2a, in the HVS-1 (source). 

While the "raw CRS" in the HVS-1 region is relatively common (specially within mtDNA H but occasionally in U* and R0 and HV as well), haplogroups with the 16129A mutation (and only that one) are not. 

In fact, after studying the matter with the help of PhyloTree, I realized that only one modern haplogroup carries that mutation: H17'27 (expanded from an original H17 finding by Roostalu in 2007, now known as H17a). I've been searching for further information and there is not much but at least the haplogroup was detected at a frequency of 0.5% in a pooled sample of Central Europe,  the Balkans and Dubai by A. Brandstätter in 2008.

Another finding was to realize that someone else had noticed this fact before I did: someone by the name of Maciamo posted his surprise at that same finding (he calls it pre-H17 but it's the same thing) at the forum of Eupedia almost a year ago.

So are we before the oldest known mtDNA H ever and finally the evidence supporting my theory that this haplogroup spread at the colonization of Europe, as the huge star-like structure it has (only comparable to that of M, produced at the beginning of the Eurasian colonization)? I believe so.

Notice that it is not mtDNA H-root, which would produce an imprecise "CRS" sequence, but already a derived lineage, indicating that the spread of mtDNA H happened before this date of 25,000 years ago, that is at least as early as the Gravettian expansion.

6 comments:

  1. There are several problems here.

    1) The limited testing of the Sunghir specimens. Had areas outside HVR1 been tested, we would be more confident of a haplogroup designation. With only one mutation from CRS in HVR1, it's sheer guesswork.

    2) The same mutation can crop up within different haplogroups.

    3) The Sunghir specimens do not necessarily have descendants in the modern population.

    4) Hapologroup H is calculated to have arisen c. 18,600 years ago and sub-groups of it more recently than that (Soares 2009). Of course ancient DNA might force a rethink, but it would have to be very, very solidly identified. Sykes jumped the gun by identifying CRS as H in early studies, so people will be much more careful now.

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  2. Thanks for your comment, Jean.

    1) Of course. It's always best to test for Coding Region (and HVS-II) mutations but, while Bramanti and others have set impressive precedents in this matter, we still see others working with the same old HVS-I-only methods (for instance the last of Haak). So we have to work with what we get (always knowing the limitations).

    2) It does not - at least not in known modern haplogroups, without other mutations pulling it away from CRS. It can only be H17'27 or a solution indistinct from CRS.

    You say in your site that HVS-I CRS is like a non-result but in fact it can only be a number of haplogroups:

    H (many many subclades)
    HV*, HV4*, HV5
    R0*
    U*, U2'3'4'7'8'9*, U8*
    R*, R2'JT*, R8, R30, P*, P4 (most of these are too exotic for Europe)

    [* here means excluding all subclades unless specifically mentioned]

    It cannot be for instance U5 nor K nor R0a nor JT nor V nor F. And it cannot be L(xR) in any case. CRS HVS-I is at least indicative of macro-haplogroup R (and normally it's H).

    3) Of course. But we have also no reason to think their haplogroup was not more extended and left some legacy (H17'27 is anyhow a rare lineage).

    4) Molecular clock speculation, no thanks. I already wrote to you on this matter and my readers are generally familiar with my strong objections in this aspect and my practice of counting mutations in the mDNA tree downstream from "Eve" and not from present to the past.

    Essentially, drift may and should impede the molecular clock from ticking (or at least slow it a lot) when the population is large enough: that's why we can observe an apparent, and even dramatic, slowing of the molecular clock downstream of the larger star-like nodes.

    As you surely know not all branches have the same length, in fact some are many times longer than their counterparts and that demands an explanation: I have one and looks good.

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  3. I left point (2) half-explained, sorry. I mean that, hypothetically, that rare HVS-I mutation might have happened in another line... but only from those haplogroups (listed above) for which the CRS HVS-I is valid (or if another/several others CRS-wise mutation(s) happened in that same line, what is most unlikely).

    So essentially it's CRS plus that mutation and it only matches H17'27 among modern known haplogroups. It'd be great indeed if we had a second mutation to be safer... but we do not.

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  4. Also, another problem in order to accept that H is so young as 18 Ka is that we know now that several H subclades (namely H1, H3, H4 and H7) spread from SW Europe into North Africa at some moment, with enough strength to define at least 25% of the modern mtDNA pool of that region. The only circumstance when this makes sense to have happened is at the genesis of the Oranian/Iberomaurusian culture, which is likely related to Iberian (Gravetto-)Solutrean, which has dates c. 22 Ka ago. The fact that we find several unmistakable H lineages in Taforalt (Oranian culture, 12 Ka ago, Kefi 2005) rather confirms this process of spread and demands at least Solutrean ages for mtDNA H1, H3, H4 and H7.

    Considering the timing and that genuine Solutrean in the Iberian province is restricted to a couple of sites near Valencia, eventually suffering from intense Gravettization from their older neighbors, this places the expansion of mtDNA H overall at least in Gravettian times, some 28 Ka ago.

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  5. "another problem in order to accept that H is so young as 18 Ka is that we know now that several H subclades (namely H1, H3, H4 and H7) spread from SW Europe into North Africa at some moment, with enough strength to define at least 25% of the modern mtDNA pool of that region. The only circumstance when this makes sense to have happened is at the genesis of the Oranian/Iberomaurusian culture, which is likely related to Iberian (Gravetto-)Solutrean, which has dates c. 22 Ka ago. The fact that we find several unmistakable H lineages in Taforalt (Oranian culture, 12 Ka ago, Kefi 2005) rather confirms this process of spread and demands at least Solutrean ages for mtDNA H1, H3, H4 and H7."

    Some recent research puts the origins of the Taforalt culture at about 17K years ago, which would be a very neat fit with an original of mtDNA H from 18K years ago, although this would still leave the Sunghir specimens as outliers.

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  6. Interesting, thanks for the link. Sadly they do not specify if their dates are BP (C-14 uncalibrated) or calBP, what may be a big difference for that period. 17,000 BP can be as old as 21-22,000 actual years ago.

    On the other hand the Iberian Solutrean earliest dates of c. 21,000 BP mean something like 24,000 years ago in real terms.

    17 Ka ago would be a bit rather late in my opinion but I imagine it is raw BP because I have seen somewhere dates of c. 20-22 Ka (also rather recent stuff). That would fit very well. Regardless of genetics, I think the case is quite clear for that contact, which may have been more important in the Eruope->Africa direction but that surely also had some feedback, as suggested by the adoption of back-tipped arrow/spear points, possibly of deep Aterian roots.

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