I have always opposed the Coastal Migration theory. The theory appears to tell either the early humans were such an idiots that they moved quickly via hospitable regions of South Asia, SE Asia to Australia from their original homeland in Africa or people who have come up with this theory have no commonsense.
A new study that examines bacterial spread from Africa to Oceania and appear to support the Northern Route (that I haven't championed much, as I don't have much evidences). Check the figure given in the paper, " The Peopling of the Pacific from a Bacterial Perspective"(Link debt to Gernan Dziebel, commenter at Music 000001)
The following figure shows how humans split in northern Asia. Though it doesn't talk about South Asia much I would say, there can be an arrow from northern Asia to South Asia.
In my opinion, there could be following migrations to the Indian subcontinent.
Initial:
1. Y-haplogroup F* from West Asia (western corridor)
2. Y-haplogroups K and C from northern Asia (eastern corridor)
Another, important thing is back migration (red line) in the figure. Does it have anything to do with Y-Haplogroup NOP?
Maybe I can also propose, at least one subclade of NOP (R-M124 or commonly known as R2).
3. R-M124 from northern Asia (eastern corridor): This at least fit the present day scenario where we find its highest frequency in eastern Indian regions and its low but widespread presence in few Siberian populations.
