Opinion Gaps in your double helix

The rest of the genealogy is boring,till 1870. We only have names. However,what’s interesting is that in early years,only names of sons were mentioned in lists of offspring. Daughters,or wives of sons,began to get mentioned by name during the 18th century. My grandfather,Rajanikanta Deb,was born in 1870. There was a premium now on knowledge of English. It is unlikely he knew of Radhakrishna Deb’s success with Persian. However,several centuries later,Rajanikanta Deb invested in learning English and reaped dividends,though most of his wealth was wiped out in the Great Depression; 1947 eliminating the rest.

At some point,the Alex Haley bug hits all of us. I mean Roots,not The Autobiography of Malcolm X.

I have always wondered if one could drag this back beyond 1500 ACE.

As an offshoot of the Human Genome project,one can do this now. I have wanted to do it ever since I read about this in Nayan Chanda’s Bound Together. He tracked his ancestry back to Africa from Gujarat. Three years ago,you could only do this in the West. It can be done in India now. The testing isn’t done in India. You give the DNA swabs in India and pay in Indian rupees. But the swabs go abroad for testing and you wait three to four weeks for the report.

These are mouth swabs of saliva,not blood. Blood samples require greater temperature control for transportation. Saliva is easier. There are other DNA-based tests that can be done,not just ancestral roots. For instance,the most popular at this particular collection centre is paternity tests. A child can also be tested to identify what diseases it is genetically prone to. The ancestry test is based on mitochondrial DNA,mitochondria being the organelle (sub-unit of a cell) in which this DNA is located. The mtDNA is inherited through the mother and my test was based on this. There is apparently some kind of mtDNA transmission that goes down the father’s line,but that test is not that reliable.

Everyone’s gene has something called a short tandem repeat (STR). This is a DNA marker that is unique to an individual and,based on this,there is an STR profile. I inherited such a marker from my father and another from my mother. But,as I have said before,the one being used is the one through the mother’s line.

There is also something called CODIS (Combined DNA Index System),with 13 codes. Once you do your test,your STR profile will list the frequency with which each of these 13 occurs in your STR profile. The next step is to match this with the presence of similar patterns across anthropological regions.

The earliest we go back to is Mitochondrial Eve. She lived in Africa,120,000 to 150,000 years ago. She had three daughters,so to speak,L1,L2 and L3. L1 stayed on in southern Africa. L2 moved to central and western Africa. The relevant line is L3. This moved to the Near East 70,000 years ago. From the Near East,one branch moved to southern Asia and Australasia 60,000 years ago and another moved to Europe and Central Asia 40,000 years ago.

I had expected my line to be the one that moved to southern Asia and Australasia. Therefore,it was a matter of some surprise that there were no markers along that expected line of migration. Instead,the matches were in Europe,not even in Central Asia. About 20,000 years ago,the markers track migration to North America and those migrants share the same codes that I do,as do markers of European migrants to Australia. But it doesn’t seem plausible that North American or Australian ancestors would have left their footprints in Kannauj. One must appreciate all this is probabilistic and stochastic,not certain or deterministic. How did a European ancestor turn up in Kannauj in UP? The logical explanation doesn’t fit the facts. As I have said,there are no matches along the expected land-route of migration towards southern Asia. That’s what Nayan Chanda found and that’s what doesn’t exist for me.

Migration patterns emerge when there are large movements of population,not when there are one-off incidents. Perhaps the answer lies in sea-based,one-off migrations through Norse adventurers and Arab traders,probably the latter,around 1,500 years ago. There was an Arab slave trade that pre-dated Islam. And we know that slaves from Europe did turn up in greater India,through ports like Debal,Janjira and Surat. Roots may have been the right image.

MtDNA hasn’t plugged the hole from 40,000 years ago to 1500 ACE. But perhaps DNA testing will evolve over time and become more specific.

For the moment,it hasn’t answered questions. Instead,it has raised many more.

The writer is a Delhi-based economist express@expressindia.com