Early Indians Page 10
The study was based on ancient DNA from 612 individuals. These ancient individuals came from many regions and periods: Iran and Turan, an old term for the region that includes Turkmenistan, Uzbekistan and Tajikistan (5600–1200 BCE); the Steppe east of the Ural mountains, including Kazakhstan (4799–1000 BCE); and the Swat valley of Pakistan (1200 BCE to 1 CE). This ancient DNA data was then compared and co-analysed with genome-wide data from present-day individuals – 1789 of them from 246 ethnographically distinct groups in South Asia. It is this comparative analysis using both ancient DNA and present-day DNA across regions and periods that allowed the study to arrive at conclusions about who moved from where and mixed with whom.9
So what did it find?
It found that an Iranian agriculturist population from around the Zagros region had contributed significantly to the ancestry of the ‘Indus Periphery’ population at least by between 4700 BCE and 3000 BCE. The study defines the ‘Indus Periphery’ population as migrants from the Harappan Civilization who were residents in neighbouring cities that the Harappans had trade and cultural relations with – such as Gonur and Shahr-i-Sokhta. Gonur is in Turkmenistan and was part of the Bactria–Margiana Archaeological Complex, a civilization that thrived between 2300 BCE and 1700 BCE. Shahr-i-Sokhta is a major archaeological site located in the south-eastern part of Iran which was occupied between 3200 BCE and 1800 BCE.
There were three ancient individuals from Gonur and Shahr-i-Sokhta that the researchers found to be Harappan migrants, and they were outliers when compared to the rest of the skeletons from the same sites because, unlike the others, they carried significant amounts of First Indian ancestry, apart from Iranian agriculturist ancestry. Since no ancient DNA has been recovered from the Harappan Civilization areas so far, these ‘Indus Periphery’ individuals stand in as proxy for the Harappan population itself.10 So that answers the question we started with: was there a migration of Iranian agriculturists into India? Yes, because ancient DNA shows that the Harappans harboured significant Iranian agriculturist ancestry. Now let us look more closely at how exactly ancient DNA helped the researchers arrive at this conclusion. The ancient DNA of people from the Zagros region of Iran between 7000 BCE and 8000 BCE showed that they harboured a distinctive type of west Eurasian ancestry. They were different from the others in the Fertile Crescent region because they lacked the Anatolian ancestry that everyone else had. In fact, Anatolian ancestry can be seen spread all the way from Anatolia (today’s Turkey) to eastern Iran and far-eastern Turan. But the ancestry keeps declining as you move from the west to the east – it ranges from 70 per cent in Anatolia to 33 per cent in Iran and 3 per cent in far-eastern Turan. The reason for this pattern of distribution of Anatolian ancestry could be that Anatolians had played a role in spreading agriculture towards the east (just as they had also spread it towards the west, into Europe). But remember, the Zagros population between 7000 BCE and 8000 BCE was unaffected by this genetic spread.
We can now look at the other crucial bits of evidence – the ancient DNA from Gonur and Shahr-i-Sokhta. In all, the study had access to the DNA of sixty-nine ancient individuals from BMAC sites and a great majority of them had this particular combination of ancestries: early-Iranian-agriculturist-related ancestry (about 60 per cent), Anatolian agriculturist-related ancestry (about 21 per cent) and west-Siberian-related ancestry (about 13 per cent).
The remains of the three individuals from Gonur and Shahr-i-Sokhta were dated to between 3100 BCE and 2200 BCE. These individuals, in contrast to the rest, had between 14 and 42 per cent of their ancestry related to the First Indians and 58 to 86 per cent of their ancestry related to Iranian agriculturists. Since they had no Anatolian ancestry, it was clear to the researchers that they came from farther east since Anatolian ancestry keeps declining towards the east. That they had significant First Indian ancestry also suggested the same – that they came from the east, from the Harappan Civilization, and were migrants to Gonur and Shahr-i-Sokhta. In other words, the study showed that the Harappan population from around 3100–2200 BCE had part ancestry from the Zagros agriculturists, while there was no indication of a First Indian ancestry in the Zagros agriculturist ancient DNA dating to 7000–8000 BCE. The direction of migration, therefore, was clear. People had migrated from the Zagros region of Iran towards India.
There was more evidence. The study had access to the DNA of forty-one ancient individuals from the Swat valley, who lived approximately between 1200 BCE and 800 BCE – about a millennium later than the outliers in BMAC and more than half a millennium after the Harappan Civilization started declining around 1900 BCE. These were genetically very similar to the three outlier samples from Gonur and Shahr-i-Sokhta, with major components of their ancestry being related to Iranian agriculturists and First Indians. (They also had a 22 per cent ancestry from the Steppe-Middle-to-Late-Bronze-Age people – the result of a later admixture that could have happened in the second millennium BCE, which we will talk about in chapter 4.)
In sum, forty-four individuals from the ‘Indus Periphery’ (BMAC, Shahr-i-Sokhta) and Swat valley during the period ranging from 3100 BCE to 800 BCE carried evidence of a significant mixing between Iranian agriculturists and the First Indians. And genetic modelling showed that the ‘Indus Periphery’ population would fit well as one of the ancestral groups of the present-day Indian population.
Here’s a recap then of how these new findings add greater detail to what we already knew. As we saw earlier, genetic studies based on present-day haplogroups had suggested significant migrations that brought new lineages to India. And studies based on whole genome sequencing of present-day populations had shown that Indians today are a mixture of First Indians and populations that are closely related to present-day west Eurasians. But these studies could not conclusively answer questions involving the direction of migration. What the latest ancient DNA-based study has done is exactly that: given a definitive answer to the question of the direction of migration, while also providing a finer understanding of the multiple migrations that caused the affinity between present-day Indians and west Eurasians. We now know that there was a migration of Iranian agriculturists from the Zagros region to the Indus Valley. From the Swat samples, we also know there was a migration from the Steppe, which we will talk about in detail later.11
When could the mixing between Iranian agriculturists and First Indians have taken place? By looking at the genetic data of the three outlier individuals from the BMAC and Shahr-i-Sokhta, geneticists can determine the latest period by which the mixing could have happened. And that works out to between 4700 BCE and 3000 BCE. (Genetics hasn’t been able to work out a similar period for the earliest period by which mixing could have happened.) But as we have seen, there is evidence for the beginnings of agriculture at Mehrgarh much earlier, from around 7000 BCE. So agriculture in Mehrgarh or elsewhere in the region could either have been begun locally by the First Indians with migrating agriculturists from the Zagros region arriving only later, or Iranian agriculturists may have moved into the region and brought with them some agricultural practices before mixing later with the First Indians, some of whom, we know, were experimenting with agriculture in places such as Lahuradewa. Of course, it could also mean that the Iranian agriculturists from Zagros arrived around 7000 BCE and mixed with First Indians around that time itself, since genetics hasn’t provided the earliest date of the mixing. There is no reason to assume that agriculture only began in one place and then spread everywhere else. It is more likely that agriculture had multiple origins, around the same time, with different degrees of success in terms of productivity and, hence, population expansion.
In all of these possible scenarios, it is clear that at some point in the trajectory of agriculture in the north-western region of South Asia, whether right at the beginning or later, there was a significant influx of Iranian agriculturists from the Zagros region whose genetic imprint on the Indian population today is writ large.
But hold on, before we conclude this ch
apter, just one more bit of evidence to complete the loop. Remember we had said that earlier uniparental chromosome studies had thrown up J2, L1 and L1c as the Y-chromosome lineages that are likely to have come from west Asia to India? So what does the ancient DNA evidence have to say about this? What haplogroups did the ancient outlier individuals from Gonur and Shahr-i-Sokhta belong to? Only two of them were male, and we know what their Y-chromosome haplogroup is. It is J2, just as the uniparental DNA study had suggested! Looking back, one can say that after the initial arrival of modern humans in the subcontinent around 65,000 years ago, and after the invention of microliths that probably led to their unquestioned supremacy in the region and their growth in population, the start-up at Mehrgarh was the most consequential development, a definitive turning point, in the prehistory of India.
The residents of Mehrgarh who raised the first mud-brick homes of two or three rooms may not have realized it then, but they were laying the foundation for the first efflorescence of civilization in South Asia, called the Harappan Civilization, or the Indus Valley Civilization. It took about 4500 years, or over 150 generations, for those humble mud-brick abodes to turn into the urban structures of a Harappa or a Mohenjo-daro or a Dholavira and there must have been many twists and turns along the way. But once agriculture took root, and modern humans started creating a surplus that they could save and invest, the wheels of history started spinning fast – which would, of course, lead to the invention of the wheel itself!
But what kind of a civilization did it lead to, and how? To that we turn in the next chapter.
Postscript: When the Harappan Civilization fell apart after 1900 BCE, the people who built it and kept it going for centuries spread out to the rest of the subcontinent – to the east and the south, in particular. To use the imagery with which we began this chapter, the people of the Harappan Civilization – a mix of the descendants of the First Indians and the Iranian agriculturist migrants – therefore became the sauce that was spread all over the crust of the pizza that is the Indian population. We will discuss this further in the epilogue.
1Jean-François Jarrige, ‘Mehrgarh Neolithic’, Pragdhara 18 (2006).
2If there were other centres of early farming in the region that were of an earlier period or were equally prominent, they are yet to be discovered.
3Nigel A. Goring-Morris and Anna Belfer-Cohen, ‘Neolithization Processes in the Levant: The Outer Envelope’, Current Anthropology (October 2011).
4For example, at the Zawi Chemi Shanidar site in north-western Zagros, the archaeologist D. Perkins Jr found a prey profile focused only on two- to three-year-old male sheep, which is different from the usual pattern for hunting (mostly prime adult male) or herding (young males and older females). Another site at Hallan Cemi, 300 kilometres to the north-west of Zawi Chemi, also exhibited the same pattern. The archaeologist Richard Redding, who worked on the Hallan Cemi site, explains that this is a variation of the prime male hunting strategy, but one practised under conditions of extreme pressure on local herds. He argues that sedentary hunters intensively exploiting prime adult males in the region could have created a vacuum that attracted young males from other regions. Effectively, the hunting strategy could have created a ‘male sink’, assuring a continuous supply of young males, while keeping the herd itself robust and ongoing. This strategy of ‘game management’ has been observed in another site in the same region called Kortik Tepe as well (8900 BCE).
5Melinda Zeder, ‘The Origins of Agriculture in the Near East’, Current Anthropology (October 2011).
6Present-day Indians also draw their ancestry from east Asia, but these two studies did not focus on that, so we will tackle this later.
7Near East is equivalent to west Asia, the terminology used in this book.
8The Bronze Age is a historical period characterized by the use of bronze. Different regions enter the Bronze Age at different times. In West Asia, South Asia and Europe, the Bronze Age begins approximately around 3200 BCE. The Bronze Age is often preceded by the Chalcolithic Age and is succeeded by the Iron Age.
9There has been criticism from some archaeologists and historians that the genetic conclusions about ancient human migrations are based on too few ancient DNA samples and are dependent on where ancient remains were chanced upon. According to them, this is like looking for a watch you lost on a street, but only on those stretches where there is lamplight. But to the extent that this argument is valid, it applies to all of archaeology and prehistory in general – in these cases too, people are looking for watches on streets, but only on those stretches where there is lamplight. More seriously, there was a time, just a few years ago, when ancient DNA samples were extremely sparse, but that is no longer the case. There is rapid discovery of ancient DNA happening all across the world, and ‘The Genomic Formation of South and Central Asia’ is based on ancient DNA from 612 individuals, which is a substantial number. It is true that analysis of ancient DNA recovered directly from a Harappan Civilization site is yet to be published, but we do have forty-one ancient DNA samples from the Swat valley of Pakistan, dating from 1200 BCE. We also have three samples of ‘Indus Periphery’ population that were recovered from Gonur and Shahr-i-Sokhta. Studying all these in combination with extensive DNA analysis of present-day populations is what allows scientists to arrive at reasonably robust conclusions. They are robust partly because each new study based on ancient DNA is filling in another part of the global puzzle of human migrations, and, therefore, conclusions have to interlock if they are not to be disputed. In other words, the robustness of the conclusions is more than it seems on the surface. However, as is the case in all of science, in all disciplines at all times, all conclusions are conclusions based on current evidence.
10Scientists have managed to recover DNA from the Harappan site of Rakhigarhi in India, but the study has not yet been published. Credible news reports about the unpublished study, however, suggest they support the conclusion of a mixing between Zagros agriculturists and the Harappans.
11To use a more technical description, we now know that the ancestry of ASI derives from First Indians (Ancient Ancestral South Indians or AASI) and Iranian agriculturists. And we also know that the ancestry of ANI comes from First Indians (AASI), Iranian agriculturists and Steppe pastoralists. Almost all present-day populations of Indians are a mixture of ANI and ASI, in different proportions in different regions and communities.
3
The First Urbanites: The Harappans
How the largest civilization of its time, with a unique set of practices and outlook, took wing. And how its creators spread the Dravidian languages and became the ancestors of both North Indians and South Indians.
It took nearly 5000 years for the seeds that were planted – literally – in the Kacchi plain of Balochistan around 7000 BCE to grow into the mighty tree that was the Harappan Civilization between 2600 and 1900 BCE.
Not all agricultural societies become civilizations, but no civilization can become one without passing through the stage of agriculture. (We’ll come to precisely what a civilization is on p. 117. For the moment let’s take the term at face value.) This is because at some stage in the development of agriculture, as productivity improves, not all people would need to be engaged in producing or procuring food. A significant number of people could be freed up to pursue other activities such as building walls or monuments for new cities; making new tools, weapons and jewellery; organizing long-distance trade; creating new artistic masterpieces; coming up with new inventions; keeping accounts; and perhaps constructing new public infrastructure such as irrigation canals that further improve the productivity of agriculture, thus releasing even more people to do new things.
Ruins of the city of Harappa. The Harappan Civilization was the largest civilization of its time.
This can happen, of course, only if a society that has transitioned to high-productivity agriculture has also, at some stage in its evolution, found a way to channel the bonanza of free time into other work fr
uitfully. In the ancient world, this often involved creating new ideologies and new hierarchies or power structures to coerce or otherwise convince large groups of people to devote their time to the new tasks for very little reward. Religion often came in handy in this process and so, sometimes, did violence.
Since the script used by the Harappans has not yet been deciphered despite nearly a century of concentrated effort by experts from around the world, we do not have enough direct, written evidence about the new ideology and power relationships that accompanied the emergence of the urban civilization of Harappa. But we get glimpses of their ideology and clues about the power structure from the seal motifs, designs, architecture and sculptures they left behind.
Almost every step of the physical, material processes that led from the two-room brick houses and barley fields of Mehrgarh to the monumental structures of cities like Harappa, Mohenjo-daro and Dholavira has been well documented archaeologically, with no major breaks or gaps in between. We can see, on the ground, farming villages spreading from the Kacchi plain to other parts of Balochistan, the Indus Valley, the Ghaggar–Hakra valley, Gujarat and beyond. Over thousands of years, they slowly grew into different regional cultures with walled towns and different styles of pottery. Then around 2600 BCE, these individual cities coalesced into what would come to be called the Harappan Civilization, spread across a vast region lying mostly along the valleys of two major river systems – the Indus, which still continues to flow, and the Ghaggar–Hakra, which has mostly gone dry since. At its peak, the civilization covered much of Pakistan, north-eastern Afghanistan and western India, including mainly the states of Punjab, Rajasthan, Haryana, Uttar Pradesh and Gujarat.