Recent advances in DNA analysis have enabled scientists to determine the parentage of people living thousands of years ago- a accomplishment that would not have been possible just a few years ago. Now, two papers have exercised genome analysis to unravel the history of people living in South and Central Asia.
The first, published in Science, involved deciphering genomes gathered from 523 archaic people who lived in a region spanning Iran, Russia, and India between 3,000 and1 2,000 year ago, representing it the largest study of ancient DNA wrote to date, the study scribes say. The project has increased the number of published ancient genomes by 25 percent and shifted the focus of that data further easts, as previous analysis has almost entirely centered on Europe. These were then compared to the ancestry of modern South Asians.
The answers depict the bulk of DNA in modern South Asians is inherited from groups of early hunter-gatherers in Iran and Southeast Asia, Bronze Age pastoralists from the European Steppe, and people from the Indus Valley Civilization. The pastoralists( also called ‘Yamnaya’) were the same group of people who took over massive swathes of Europe circa 4,000 year ago, and it is this connection that the study writers conclude justifies the linguistic similarities between Indo-Iranian and Balto-Slavic limbs of Indo-European language.
“Our maps in this study illustrate how transcontinental gene flow derived over vast territory and thousands of years, but one must be careful not to examine these genetic arrows as colonial takeovers- in fact, our data show that human mobility frequently brought about gradual change over the span of centuries, and sometimes millennia, ” co-senior author Michael Frachetti of Washington University, said in a statement.
The second study, published in Cell, reports on the first-ever successfully sequenced genome of a member of the Indus Valley Civilization, a Bronze Age civilization that comprised the northern part of South Asia, was once larger than Mesopotamia, and disappeared mysteriously 4,000 year ago. Researchers looked at the DNA of a single woman, who died virtually 5,000 years ago in the Indus Valley at a site called Rakhigarhi, approximately 150 kilometers northwest of Delhi. The crew was( eventually) able to extract enough DNA from the skeleton’s ear bone, but it was no easy task and made more than 100 attempts. The region’s hot climate intends skeletons like these are often found in poor condition- undoubtedly, hundreds of skeletons from the Indus Valley ought to have acquired but she was the only one of 61 sampled that produced genetic material.
“There’s no doubt this is the most intensive effort we’ve ever made to get ancient DNA from a single sample, ” said David Reich, a geneticist at Harvard University, Science reports.
Testing discovers the skeleton was most likely a woman who lived sometime between 2800 to 2300 BCE, and that her family was a combination of South Asian hunter-gatherer and Iranian. Interestingly, the latter one of the purposes of her DNA was found to predate the Fertile Crescent’s farming revolution circa 10,000 years ago by nearly 2,000 years.
This belies presumptions that the farmers of the Fertile Crescent- an domain that includes today’s Iran- moved eastwards and mingled with South Asian hunter-gatherers, and shows the Iranian hunter-gatherers who preceded them were already at it. It also therefore seems that farming wasn’t introduced to South Asia by the migration of those working in the Fertile Crescent but instead, agriculture developed in the two regions separately and independently- or through cultural contact.
This skeleton was not a one-off. Eleven others analysed in the first study exposed similar genes, hinting they were migrants( or progenies of) from the Indus Valley. Still, the team hopes to analyze more DNA from Indus Valley websites and create an even clearer picture of the mixing of people and cultures in ancient Asia.
“What we see in both in the isotopic information as well as the archaeological knowledge is sold and exchange of agricultural information and production happening in both directions, ” Vagheesh Narasimhan, co-first author of the first study, said in a statement.
“Now with the ancient DNA, we’re actually seeing that in the people, ” he explained. “It’s giving us confidence to understand what happened in the past and how this process is happening.”