
Originally Posted by
Coldmountains
This question can only be fully answered with ancient dna from Arabia of course but i remain sceptical because L657 in Arabia before 600 A.D because L657 is pretty much absent among Christian Arabs, Jews, Kurds, Assyrians and even rare among Persians. It peaks in the Gulf region were a big presence of Indian, Baluch and other Iranic immigrants is documented. From here these lines could diffuse deeper into Arabia in the last 1500 years.
Arabs are extremely "oversampled" at Yfull and FTDNA compared to Baluchs, Afghans, Iranians and Indians, which likely have very similar L657 clades so some old L657 subclades looks at Yfull specific for Arabs, but with better sampling i doubt this will be still the case. For now most of the Indian L657 samples on Yfull are just from few academic studies and few private Indian L657 samples were uploaded at Yfull.
L657 orginates in Fatyanovo-Abashevo and Corded Ware. It arrived via Central Asia/BMAC in South Asia. Some speculate that Mitanni Indo-Aryans in Bronze Age Syria were R1a-L657, because they were Indo-Aryan speaking, but this is for now just speculation and some Indo-Aryan groups like Kalash lack L657 and are dominated by R1a>Z2124>Z2123. Z2123 is also not rare among Indians so there is a good chance Mitanni in the Near East lacked L657 and were rather dominated by Z2123. For me L657 rather looks like a line specific/typical for a subset of Bronze Age Indo-Aryans, which via Arachosia migrated into South Asia. So we still see lot of L657 in Gedrosia/Arachosia and India but less so in Iran, Kafiristan and West Asia, which all have or had an Indo-Aryan presence once. But again only ancient dna can give us an answer here and maybe i am mislead by modern distribution of L657.