One thing is marriage another is sexual relations.
Yes, a different reality from Brazil, it was not a colinisation in Goa but a conquest.Afonso de Albuquerque, probably the greatest Portuguese general, encouraged his soldiers to marry the locals in India after he conquered Goa and Malacca, for example. This is the origin of the Kristiangs.
His measures were in fact rejected by the society, the assimilation of the remaining new-christians only became more effective after the liberal revolutions.Pombal also stopped the practice of 'limpeza de sangue', making it impossible to know among the Portuguese who had Jewish ancestors and who didn't. Before that, apparently it was very easy to verify if one had these ancestors. After his measures, it became impossible.
There were some means of tracing the ancestry of the families, the priests and inquisitors knew all the families.
Yes, some upper class families can even trace their ancestors back to 1500-1600's, altough their number is not very significant to the whole.And, regarding AlexdeLarge's post I quoted earlier, Portuguese settlers still came after the initial wave. All the Portuguese blood in Brazil doesn't come from just João Ramalho and later the immigrants of the 19th and 20th century. The genealogy of former president Getulio Vargas, for example, shows only Portuguese from Azores 6 generations earlier, in the 1700s: