The Pith: Afro-Indians are mostly African, with a substantial Indian minority ancestry. The latter is disproportionately female mediated. It also seems that that ancestry is more northwest Indian, and that natural selection has been operating upon them outside of the African environment.
Along the western coast of South Asia, from Makran in southwest Pakistan, down to the Konkan coast of southwest Iindia, there are isolated communities of Afro-Indians. They are called Siddis or Habshi. Their African origin is clear in their physical appearance, as well as aspects of their folk customs which tie them back to Sub-Saharan African. Nevertheless, they have assimilated to many Indian cultural traits. They generally speak the local language, and practice Islam, Hinduism, or Roman Catholic Christianity (in that order in proportion).
How and why did the Siddis arrive in India? The earliest date for their arrival almost certainly must be bounded by the period when Indo-Islamic polities rose to prominence in the early second millennium. The cosmopolitan melange of the armies of the Muslim warlords included diverse groups of Africans, some of whom took power, and established their own self-conscious Afro-Indian dynasties, set apart from the Turkish, Afghan, …