Source: – Sanjeev Sanyal / Twitter.
I keep seeing debates on genetic lineages. Hence need let people know some general technical issues. Genetic archaeology can be done through, Y, X and autosomal DNA. The last is the basis for ASI-ANI type framework for Indian genetic history. 1/n
— Sanjeev Sanyal (@sanjeevsanyal) March 31, 2018
The Y and X are the male and female lineages (hence relatively neater), while the autosomal gets mixed & fuzzy within a few generations, hence requires qualitative modelling. Since it is dependent on the model being used, it is less reliable over long range time 2/n
— Sanjeev Sanyal (@sanjeevsanyal) March 31, 2018
This autosomal approach is especially messy when we dealing with groups mixing over long periods of time and, in my view, breaks down if we have back-and-forth migrations (i.e. a braided stream rather than unidirectional branching out) 3/n
— Sanjeev Sanyal (@sanjeevsanyal) March 31, 2018
There is always a danger that the model choice in autosomal studies will lead to cognitive reinforcement. The Y and X data is much more painstaking to collect, but more reliable. In my view, autosomal studies should be used very carefully to provide color to XY based analysis 4/n
— Sanjeev Sanyal (@sanjeevsanyal) March 31, 2018
This brings me to larger point. Genetic data is useful evidence, but should be used carefully (and should be weighted together with other hard evidence like archaeology, climate studies etc). 5/n
— Sanjeev Sanyal (@sanjeevsanyal) March 31, 2018
If one were reconstructing British colonial history purely on the basis of genetics, one would conclude that Indians conquered Britain and not the other way around 6/n
— Sanjeev Sanyal (@sanjeevsanyal) March 31, 2018
A number of interesting papers should be out in the next two years. Wait for the full sequence before jumping to conclusions. My reading of the data is that the ancients were more mixed up than people realise. The ASI will have Iranic links, ANI with SE Asia and so on 7/n
— Sanjeev Sanyal (@sanjeevsanyal) March 31, 2018
This fits with growing data we are not even a "pure" species descended from a single Out of Africa migration but carry plenty of genes from other hominids who already lived is Europe and Asia before we turned up 8/n
— Sanjeev Sanyal (@sanjeevsanyal) March 31, 2018
