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From the paper "A genetic chronology for the Indian Subcontinent points to heavily sex-biased dispersals":
yet Yamnaya, no matter if that was a Copper Age culture.
In the last 4 ka, most genetic influx on the maternal line
was restricted to Pakistan and traces mostly to Iran (H29 + 9156 + 4689, R2a + 7142 and U1a1a2a) (2.4% in
South Asia, reaching 5.4% in the western populations).
Gene flow at this time was clearly bi-directional, as seen
in the expansion west of lineages M5a2a4, U2c1b + 146
and M3a1b + 13105). This is reflected in the genomewide
ADMIXTURE analysis (below), where the autochthonous
South Asian component (green in Fig. 2a) appears
at low levels in Iran.
The Yamnaya aDNA samples are scattered around the
Central Asian and Pakistani groups (Additional file 1:
Figure S8), confirming the ADMIXTURE results
(Additional file 1: Figure S6), and suggesting links
between the Bronze Age Steppe and today’s Central Asia
and Indian Subcontinent.
yet Yamnaya, no matter if that was a Copper Age culture.
A markedly higher proportion of male lineages of
likely West Eurasian origin, of ~50–90%, is evident
across the Subcontinent (Fig. 3c), in comparison with
both the maternal line (Fig. 3b) and the GW pattern
(Fig. 3d). A sex-biased pattern is also seen in the East
Asian fraction, but is much less marked, with a much
lower contribution overall and mainly focused on
speakers of Tibeto-Burman and Austroasiatic language
families [22].
Given the difficulties with deriving the
European Corded Ware directly from the Yamnaya [96], a
plausible alternative (yet to be directly tested with genetic
evidence) is an earlier Steppe origin amongst Copper Age
Khavlyn, Srednij Stog and Skelya pastoralists, ~7-5.5 ka,
with an infiltration of southeast European Chalcolithic
Tripolye communities ~6.4 ka, giving rise to both the
Corded Ware and Yamnaya when it broke up ~5.4 ka [12].
There are now sufficient high-quality Y-chromosome
data available (especially Poznik et al. [58]) to be able to
draw clear conclusions about the timing and direction of
dispersal of R1a (Fig. 5). The indigenous South Asian
subclades are too young to signal Early Neolithic
dispersals from Iran, and strongly support Bronze Age
incursions from Central Asia. The derived R1a-Z93 and
the further derived R1a-Z94 subclades harbour the bulk
of Central and South Asian R1a lineages [55, 58], as well
as including some Russian and European lineages, and
have been variously dated to 5.6 [4.0;7.3] ka [55], 4.5–
5.3 ka with expansions ~4.0–4.5 ka [58], or 4.7 [4.0;5.5] ka
(Yfull tree v4.10 [54]). The South Asian R1a-L657, dated
to ~4.2 ka [3.3;5.1] (Yfull tree v4.10 [54]]), is the largest (in
the 1KG dataset) of several closely related subclades
within R1a-Z94 of very similar time depth. Moreover, not
only has R1a been found in all Sintashta and Sintashtaderived
Andronovo and Srubnaya remains analysed to
date at the genome-wide level (nine in total) [76, 77], and
been previously identified in a majority of Andronovo
(2/3) and post-Andronovo Iron Age (Tagar and Tachtyk:
6/6) male samples from southern central Siberia tested
using microsatellite analysis [101], it has also been identified
in other remains across Europe and Central Asia ranging
from the Mesolithic up until the Iron Age (Fig. 5).
Although they are closely related, suggesting they likely
spread from a single Central Asian source pool, there
do seem to be at least three and probably more R1a
founder clades within the Subcontinent [58], consistent
with multiple waves of arrival.
For example, haplogroup H2b (dating to
6.2 ka [3.8–8.7] ka; Fig. 6) is a starlike subclade with a
probable ultimate ancestry in Eastern Europe, but includes
several South Asian lineages (from Pakistan, India and Sri
Lanka) that probably arrived more recently from Central
Asia. Tellingly, H2b also includes two aDNA samples
(Fig. 6): one individual from the small number of Yamnaya
sampled to date [53, 76] and another from the Late
Bronze Age Srubnaya culture [77].
indeed, a
sizeable fraction of the non-R1a West Eurasian Ychromosome
lineages (e.g. R2a-M124, J2-M241, L1a-M27,
L1c-M357) were most likely associated with the spread of
agriculture or even earlier expansions from Southwest
Asia, as with the mtDNA lineages [55, 59]. The