хехе, рецензенты таки заметили несоответствие фактических данных и выводов препринта:
https://static-content.springer.com/esm/art%3A10.1038%2Fs41467-018-08220-8/MediaObjects/41467_2018_8220_MOESM2_ESM.pdfReviewer #2 (Remarks to the Author):
...
Line 640
This hypothesis about the Caucasus source of Proto-Indo-European has been advanced also for
slightly other reasons by David Reich and Kristian Kristiansen, so I think it should be elaborated here
by the authors and they should marshall their new results to add whatever support they can.
However, this hypothesis should rest on showing a sustained admixture between Maikop and
Yamnaya to serve as a bridge to Yamnaya from the Caucasus (because the authors accept Yamnaya
as connected to later PIE.) It is difficult to see in the results presented here a sustained gene flow
from Maikop into Yamnaya, that would sustain this hypothesis. On lines 410 and 432 the authors
preferred to see the Anatolian Farmer genes that appeared in Yamnaya as flowing from
southeastern Europe, with a 20% WHG component, not from Maikop, without the WHG component.
If most of the c. 15% Anatolian Farmer found in Yamnaya came from the west, it leaves very little
room for gene flow into Yamnaya from Maikop. If the 3% WHG that makes the difference between a
western and Caucasian source of Anatolian Farmer is strongly supported by their data, that makes a
Caucasian origin of PIE less likely because it reduces gene flow from Maikop into the steppes. In fact
it suggests that very little south-to-north gene flow occurred during the Maikop period (except into 2
individuals from a distinct, small, local genetic group different from Maikop and Yamnaya). This is
puzzling and unexpected, but also it fails to support the bridge that seems to be needed.
...
если Майкоп был "мостом" между Кавказом и Ямной, то для поддержки гипотетической "Южной прародины" необходим адмикс Майкопа в Ямной, существования которого в данной работе как-то не видно.
ответ авторского коллектива состоял в том, что, де, это недоразумение. а поток генов между Кавказом и степными популяциями (за исключением нескольких примеров) действительно был очень ограничен
А в качестве основания для своих
предположений относительно Южной прародины авторы используют усиление компонента CHG к северу и югу от Кавказа
...
Reply: We’re afraid that this might be a misunderstanding. There is indeed very limited gene flow
between the Caucasus and the steppe groups (apart from the examples highlighted). However, we
have based our PIE-related speculations on the observation that the CHG/Iranian (green) ancestry
component is increasing already during the Eneolithic north of the Caucasus. This led us to propose
that this might be the actual ‘tracer dye’ of an early PIE spread, which could then also accommodate
the spread of PIE south of the mountain range where this ancestry component also rises in frequency
resulting in a relatively homogenised dual ancestry (Anatolian + Iranian farming-related ancestry) in
Chalcolithic times (see also brown arrow in Figure 2).
...
Сомнительная логика
Причем, надо заметить, что, видимо для поддержки собственной гипотезы, они постоянно путают/объединяют CHG и компонент Иранского неолита, что тоже не ускользнуло от рецензентов:
Lines 236 and 238 (again on 544 and 549): To describe the components of ancestry in the
same sample, EHG & CHG is used on line 236 (544) and EHG & CHG/Iran on line 238
(549). I understand that Iran Neolithic is largely CHG, so distinguishing between them can be
difficult. But CHG should have a clear definition and referent, and be used consistently. If
CHG/Iran is used to indicate analyses where CHG could be replaced with Iran Neolithic
without changing the result (which seems to be the explanation for lines 236 and 238) then
that statistical definition of CHG/Iran should be stated and used consistently. If CHG/Iran is
used to indicate CHG & an additional Iran Neolithic ancestry component, then that
accretional definition should be stated, or if this accretional definition is never intended, then
that should be made clear.
авторы соглашаются и признают, что они действительно могут различать CHG от собственного "ираноподобного" адмикса
Thanks for pointing out the inconsistency in describing CHG and Iran-like ancestry. We
agree that Iran Neolithic is largely CHG as shown in qualitative analysis such as
ADMIXTURE components, but we can still distinguish them quantitatively in qpWave and
qpAdm modeling because of the difference in their proportion of “basal Eurasian” ancestry.
We have checked the manuscript for consistent use of the terminology and added clarifying
statements where an absolute distinction of the two related ancestries is needed.
ну и тон выводов стал более осторожным:
препринт
...
The insight that the Caucasus mountains served not only as a corridor for the spread
648 of CHG/Neolithic Iranian ancestry but also for later gene-flow from the south also has
649 a bearing on the postulated homelands of Proto-Indo-European (PIE) languages and
650 documented gene-flows that could have carried a consecutive spread of both across
West Eurasia17, 64 651 . Perceiving the Caucasus as an occasional bridge rather than a strict
652 border during the Eneolithic and Bronze Age opens up the possibility of a homeland
653 of PIE south of the Caucasus, which itself provides a parsimonious explanation for an
654 early branching off of Anatolian languages.
...
публикация
To emphasise our point, we rephrased the start of the paragraph as follows:
“The insight that the Caucasus mountains served as a corridor for the spread of CHG ancestry north
but also for subtle later gene-flow from the south allows speculations on the postulated homelands of
Proto-Indo-European (PIE) languages and documented gene-flows that could have carried a
consecutive spread of both across West Eurasia20, 68. This also opens up the possibility of a homeland
of PIE south of the Caucasus, which itself offers a parsimonious explanation for an early branching off
of Anatolian languages, as shown on many PIE tree topologies69, 70, 71, 72.”
Тема: дДНК с Северного Кавказа, медный и бронзовый век(Майкоп, препринт) (Прочитано 70742 раз)