Proportion of steppe/Aryan origin varies among caste groups (some places as you go farther from cow belt that were subject to Brahminization or like Kashmir are exceptions to this, however this doesn’t mean all Hindus in Kashmir were Brahmins regardless of what certain recent films might claim on the subject) Physiognomy as some of the British attempted is not a golf way to go about studying it (see Native American skulls as to why, brachycephaly etc can be influenced by environment over generations) Markers like sickle cell trait (which I possess incidentally) are almost always found among aboriginal/tribal lower castes . It seems that story of “dasas” and Nishadas largely matches up with being forced into lower caste hood or untouchability as a result of losing wars.