Kinship group based on actual or purported descent from a common ancestor, as traced through the male (patriclan) or the female (matriclan) line. Clans are normally exogamous, marriage within the clan being regarded as incest. Clans may segment into subclans or lineages, and genealogical records and myths may be altered to incorporate new members who lack kinship ties with the clan. Clan membership may be useful in ensuring mutual support and defense as well as in the mediation of disputes over property rights and the mode of residence after marriage. Some clans express their unity by means of a common emblem. See alsoexogamy and endogamy.