A recently published
paper by Zeng et al of the Stanford University proposes socio-cultural
causes for the sudden and simultaneous appearance of a ‘bottleneck’ in
Y-chromosome diversity across the Old world (Asia, Europe and Africa) around 5000
-7000 BP. The two limits of this date correspond to eventful India of those
times with the lower date coinciding with the traditional date of Mahabharata and
the upper with Ramayana period extending upto Yayati’s times whose descendants spread
out to Europe. The authors’ postulation of socio-cultural causes for this
bottleneck further reiterates the suitability of the events in India of those
times in giving rise to a bottleneck in male lineage across the world and more
intensely in Eurasia.
The paper by Zeng et al is an improvisation or
development over a previous
paper published in 2015 by Karmin et al of Arizona University. The extent
of the bottleneck proposed by Karmin et al was 4000 -8000 BP which is also very
much within the span of momentous events in India. A sudden drop in genetic
diversity of male centric Y-chromosome had happened in this period while the
female centric mtDNA had continued to thrive without any reduction. The authors
did not see the reduction in Y chromosome diversity as a case of biological
survival of the fittest, but of a “reproductive success of a “limited number of
‘socially fit’ males and their sons” caused by “the accumulation of wealth and
power”
Using the same data, Zeng et al hypothesized the
effect of repeated wars over generations in wiping out many male lineages while
losing considerably the males of their own clan thereby leading to a drop in
male genetic diversity. The tricky part is that there was a sudden and sharp
drop in genetic diversity of male chromosome but not in the overall size of the
male population. There is no such change in female diversity and population-size.
These made them fine tune their hypothesis by comparing the patrilineal and
non-patrilineal groups. Their models showed acute loss of diversity in
patrilineal groups - in the lineages from a common ancestor - to the extent
that there was just one male for 17 women.
According to them a common cultural ethos promoted
high levels of Y-chromosomal homogeneity from a common descent and also ‘high
levels of between-group variation’. The presence of many groups of common
patrilineal descent also resulted in inter-group competition, leading to clashes
that wiped out lineages, which is genetically perceived as a drop in genetic
diversity. Their computer simulations of patrilineal societies showed early
extinction of many haplogroups in the beginning with one or many other
haplogroups quickly becoming dominant in frequency. The same is not found in
non-patrilineal societies where very less number of haplogroups became extinct
and overall representation continued till the end of simulation.
The inference from a layman point of view is that different
groups that sprang from a common ancestor did undergo a politico-military
survival of the fittest for a couple of millennia between 5000 -7000 BP (or
4000 -8000 BP as per Karmin et al) and ended up with specific groups among them
becoming dominant and continuing the progeny. The surprising element is the simultaneity
of this phenomenon across the Old World.
The Old World covered by Karmin et al was Africa,
the Andes, South Asia, near East and Central Asia, Europe and Oceania. The
DNA samples were taken from 456 males from these regions for the study. Following
illustration shows the sampling locations.
The dominant feature of this map is
non-representation of China in the study. It is difficult not to think that the
sampling pattern of Eurasia follows the popular conception of western academia of
PIE or IE or Aryan migration from central Europe to India (South Asia), leaving
out China. The socio-cultural hypothesis of this study is presumed to be largely
influenced by the western perception of PIE.
Another feature that catches up attention is why neither
of the teams left untouched the most striking feature, namely the surprising simultaneity
of the bottleneck in all these regions across the globe. Though the bottleneck
lifts are connected with the rise of regional polities and statehood in the
respective regions, what caused the bottleneck around the same time in all the seven
regions of the five continents leaves very less to speculate. Was there a singular force having a global
reach?
To answer this, let us take a look at the bottleneck
curves for all these regions. They tell
a story of their own which Zend et al did not probe.
In the above map the red curve represents mtDNa and yellow
curve, Y-chromosome. The sudden dip in the yellow curve (Y-chromosome) in all
the regions in the period 5000-7000 BP (or 4000 -8000 BP), except Siberia and
Andes is striking. The bottleneck is less extreme in South East and East Asia
whereas it is more in Near East and Europe. But Zeng et al clubs together West
Asia, Europe and South Asia in their paper as having similar trend which is not
true as per this figure.
South Asia (India) presents a unique shape of a
winnowing basket or a flat bottomed bowl and not a sharp curve as with Europe
and Near East. This covers a longer time period than it is for other regions. The
figure shows that the drop in male genetic diversity had started soon after
10,000 BP.
One can see the yellow curve gradually dropping down
even since 10,000 BP and flattening a couple of millennia later. The lift comes
approximately another 4000 years later. That is, for a period of roughly 6000
years since the beginning of 10,000 BP the male genetic diversity had been much
less. Applying the rationale of Zeng et al, this period had seen a severe and
continuing power struggle within the same patrilineal clan.
Such prolonged dip is found only in India and not in
any other regions under study. In other regions the bottleneck is found
simultaneously in the period 5000 -7000 BP which falls well within the flat
bottom period of India between 4000-10,000 BP.
Only other exception is Central Asia which however
has been explained by Zeng et al.
They say,
“Central Asian pastoralists, who are organized into
patriclans, have high levels of intergroup competition and demonstrate
ethnolinguistic and population-genetic turnover down into the historical period.
They also have a markedly lower diversity in Y-chromosomal lineages than nearby
agriculturalists. In fact, Central Asians are the only
population whose male effective population size has not recovered from the
post-Neolithic bottleneck; it remains disproportionately reduced,
compared to female estimates using mtDNA. Central Asians are also the only
population to have star-shaped expansions of
Y-chromosomes within the historical period, which may be due to competitive
processes that led to the disproportionate political success of certain
patrilineal clans.”
The above figure is self-descriptive of a power struggle
or unrest in Central Asia with a continuing lower diversity of male lineages
for thousands of years. However the sudden dip has happened in 5000-7000 BP in
tune with other regions.
A glaring feature in this scenario is that South
Asia is in the centre of the all the regions that experienced the bottleneck simultaneously.
And South Asia experiencing the bottleneck for a much extended period within
which the bottlenecks occurred in the surrounding regions makes it plausible
that South Asia was the epicentre of the struggle
that resulted in dispersal to the neighbouring regions. The power struggle
among the dispersed clan in the newly settled regions had caused the sudden dip
in the male diversity between 5000 -7000 BP.
Even though Southeast and East Asia enjoyed a steady
and higher coalescence between female and male lineages, the bottleneck did
appear in the same period as in Europe but less intensely. For Europe, Central
Asia and South Asia, the authors echo the same sentiment as PIE proponents of a
distribution of pastoral culture. But the large flat bottom of South Asia does not
correspond to the pastorals coming from Europe and causing bottleneck in India
in the power struggle. Contrary to that the figure suggests a long history of
sibling rivalry in India ever since 10,000 BP and a spill over to Europe and
central Asia. The history of Bharat known from Itihasas and Puranas also
establish this spill over due to power struggle among same patrilineal clans.
The most well known spill over was that of Yayati clan. Even Ramayana
accounts for the spread of the kins to distant lands to establish independent suzerainty.
By Mahabharata times struggle for power has become a regular norm with numerous
clans of west Asia and Europe siding with the two sides that belonged to the same
Kuru clan. One can say that Mahabharata war was a high point of a clash of
patrilineal clans that caused a severe bottleneck in the male progeny. Needless
to say that the revival from bottleneck coincided with post Mahabharata period,
in 4000- 5000 BP.
Historical evidence from India on
patrilineal group struggle.
Sibling rivalry is inherent in human nature. Having
understood the extent of damage it could do to a family, the early ancestors of
Bharat had favoured migration to distant lands and setting up polity by conquering
those regions. For a long time since Manu, transfer of power was to the eldest
son only. The Ikśvāku-s followed that tradition (VR 2-110-35). The
younger siblings had to see newer pastures.
Rama himself says this in justifying his acceptance
of Vibhishana. Kin of the same family do not see eye to eye. (VR 6.18.10 and 14)
“It is told that persons of the same family and
rulers belonging to adjoining territories become enemies and strike in times of
adversities. For this reason, he (Vibhishana) came here.”
“Kinsfolk do
not live together in a fearless mode and in a delightful manner. Hence, they
get a split among themselves.”
Rama envisions a personal enmity between the
brothers, Vibhishana and Ravana and justifies that it is common to see this – a
perfect example of the patrilineal enmity that Zeng et al proposes to explain
the genetic bottleneck.
The enmity and rivalry forced the siblings to go to
distant places to set up their own kingdoms and start dynasties in their name. The Chola dynasty was one such
off-shoot of the Solar dynasty that traced its beginnings to Ikśvāku. The presence of many branches of lineages and
the mix-up of names of ancestors in the chronology given by Puranas can be
attributed to this.
The first ever migration of siblings was that of Amāvasu,
whom the western Indologists see as a migrant Aryan. Amāvasu was one among six
children born to Pururavas and Ila, the daughter of Manu. The eldest was Āyus who became the
inheritor of the throne (VR 4.7, MB 1.75).
The kingdom was his and there was no need for him to look for newer pastures. This
is also ascertained from the name Āyu – that has
many meanings, among which ‘descendant’ or ‘offspring’ are suitable for him as the
eldest son. On the other hand, Amā in Amāvasu
means ‘in the house of’ or ‘non-authority’, indicating a co-existence with his
eldest brother.
A verse in Baudhāyana
Śrautasūtra
suggests that Amāvasu went
to the West in the regions of Gāndhāra, Parśu and Arāṭṭa. Further
movement to West Asia and Europe was well within reach of those who left home.
Sage Vishwamitra was the 11th descendant of Amāvasu and he preferred
to stay in Bharat.
Yayati clan.
Another important patrilineal clan that dispersed
out of India comes from the house of Yayati. This family has all features of a
mix of European and Indian races. One of the wives of Yayati was of Danu’s
lineage. Of the three sons born to her two went out of India due to sibling
fights while one stayed back in India and continued the progeny that can be
detected as a strong European mtDNA mix-up in Indian population.
Of the two who went out of present-day boundaries of
India, Anu went to the West and Druhyu to North and North West (central Europe). They
would not have gone alone but accompanied with their well wishing kin. Conquests
of new regions could have happened in the following period causing considerable
extinction of native lineages.
While on the West this march was going on, an expedition
was launched on East Asia too. Puru, the other sibling of Anu and Druhyu who
stayed back in India had a son named Janamejaya. The son born to Janamejaya
went to the countries to the east of India till the region where the sun rises –
a reference to Udayagiri
in Fiji Islands. Ramayana also describes the route till Udaya Parvata (VR 4.40.
54, 55) indicating the familiarity with the regions of the east and frequent
travels to them.
The son of Janamejaya and grandson of Puru was
perhaps inspired by the western occupation of Puru’s siblings and tried his
hand in conquering eastern part of the globe. It is for the reason that he
brought eastern countries under his power, he was called as “Prachinvat” (MB 1-95).
Thus we have two records in ancient history of Bharat
of the same paltrolineal clans making inroads in West and East of India. Those
who went to West ended up in power struggle later that finally reflected in
genetic bottleneck. Such violent reflections were less in the eastern sector.
But the simultaneity of the bottleneck in the west and east of India has the
backing of history of India in Anu and Druhyu in the west and Prachinvat in the
east.
Rama was born 20 generations
after Anu as per the genealogy given in Vishnu Purana 4-18. Rama was not
genetically connected with Anu but his father’ friend Romapada was the 20th
descendant of Anu. Assuming 3 generations for a century, Rama can be presumed
to have been born 700 years after Yayati.
The flat bottom of the bottleneck coincides with
Rama’s period (7000 BP as per Pushkar Bhatnagar’s decipherment of Ramayana and the
corresponding date of sage Agastya, a contemporary of Rama, which is known from
the sighting of star Agastya to the north of Vindhyas for the first time ).
Though Rama was wary of sibling rivalry of other dynasties, he didn’t experience
the same in his family. But all his brothers and brothers’ sons set up kingdoms
in far off regions with Bharat’s sons reaching to North West India.
Rama’s reign was felt far and wide – in west Asia
too, known from the fact that many cities of West Asia and Middle East had
their name connected to Rama. The relative calm in rivalry for the next millennium
perhaps ensured a horizontal progression of the genetic curve. This ended by
Mahabharata times, which saw extermination of own lineages and other lineages as
well. By the end of Mahabharata war the territorial rights were more or less
established and this is made out from lifts from bottlenecks.
An expansion of each of the above mentioned historic
events will stretch further this monograph. But what is to be made out is that
India had a prolonged history of struggle for power among the clans of a common
ancestor. The loss of males in wars and occasional loss of complete lineages is
more palpable in the research study matching with history. This is bound to
have a profound impact on dismantling the Aryan Invasion ideas.
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