Local populations became entrenched, eschewing intermarriage with other groups and adopting a cultural pattern of what researchers call endogamy, the practice of marrying only within an ethnic or social group. (sciencemag.org)
Although a distinct community with near total endogamy, have not perserved Indian languages or customs. (ambergrisCaye.com)
Jews were supposed to practice endogamy — that is, marriage within the 12 tribes of Israel. (religion-online.org)