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Asian cousins. 28 Since the M458 mutation is estimated to be at least 8000 years old, the two
     populations appear to have separated before or during the Great Flood. Thus, the
     genetic linkages between North Indians and East Europeans are best explained by the
     sharing of a distant common ancestor, perhaps from before the end of the last Ice
     Age. We do not really know why the Asian and European branches separated, although
     it is tempting to assume that it had something to do with climatic changes.
    Note that the most common lineage in
     Western Europe is R1b. This is related to R1a1 and possibly also originated in the
     Persian Gulf area but the two lineages separated a long time ago—probably
     during or before the last Ice Age. Compared to R1a1, India has relatively low
     concentrations of R1b. My interpretation is that we are dealing with two major
     genetic dispersals occurring from the Persian Gulf-Makran-Gujarat region at
     different points in the climatic cycle—one occurred at the onset or during
     the last Ice Age with R1b carriers heading mostly west, and another occurred around
     the time of the Flood involving R1a1 carriers.
    The genetic and cultural links between
     North Indians and eastern Iranians are due to the second dispersal but possiblywith additional inputs from a later migration of some lineages
     north-westward from India. 28 As we shall see in the next chapter, there is reason to believe that some
     Indian tribes moved westward to Iran and beyond during the Bronze Age. In addition,
     cultural linkages could have been kept alive by trade. The spread of Indian culture
     to South East Asia in ancient times and, more recently, the accelerated popularity
     of the English language in the post-colonial period show that one does not need
     either conquest or large-scale migration to drive linguistic and cultural exchange.
     The reality of complex back-and-forth linkages make it very difficult to decode
     history using the linguistic layers. This may explain why traditional timelines
     based on linguistics were far shorter than those being suggested now by genetics and
     archaeology.
CASTES OR TRIBES?
    There is one further insight that
     genetics hints at—the dynamics of India’s caste system. India is
     not unique in having developed a caste system. Through history we have seen
     different versions of the caste system in Japan, Iran, and even in Classical Europe.
     What is remarkable about Indian castes is their persistence over thousands of years
     despite changes in technology, political conditions, and even religion. The system
     has even survived centuries of strong criticism and opposition from within the Hindu
     tradition.
    It was once thought that the caste
     system had something to do with the Aryan influx and the imposition of a rigid
     racial hierarchy. However, as geneticist Sanghamitra Sahoo and her team have shown:
     ‘The Y-chromosomal data consistentlysuggest a largely
     South Asian origin for Indian caste communities’. 30 Genetic studies suggest that Indian castes are profoundly influenced by
     ‘founder events’. Roughly speaking, this means that castes are
     created by an ‘event’ when a group separates out and turns
     itself into an endogamous ‘tribe’. Over time this process leads
     to a heterogeneous milieu of groups and sub-groups, sometimes combining and
     sometimes splitting off. The result is that, despite centuries of mixing, we do not
     have a unified population but a complex network of clans. This is a good description
     of the messy ‘Jati’-based social system that exists to this
     day
    Genetics also tells us that there is no
     real difference between groups that we differentiate today as
     ‘castes’ and ‘tribes’. As India’s
     leading geneticist, Dr. Lalji Singh puts it, ‘It is impossible to
     distinguish castes and tribes from the data. This supports the view that castes grew
     directly out of tribe-like organizations during the formation of