Patrilineality

Patrilineality, sometimes called the male line, spear side, or agnatic kinship, is a system where a person’s family ties are traced and recorded through their father’s line. This usually means that property, rights, names, or titles are passed down among relatives connected through male kin. It differs from cognatic kinship, which can follow any mix of lineages, and from matrilineality, which traces through the mother’s line. A patriline is a person’s father and earlier ancestors, but only counting males.

In the Bible

In the Bible, family and tribal membership are passed through the father. For instance, someone is a priest or Levite if their father is one, and all members of the Twelve Tribes are called Israelites because their father is Israel (Jacob). The New Testament opens by tracing Jesus Christ’s descent through the male line from Abraham, through King David, to Joseph, Mary’s husband.

Agnatic succession

Patrilineal or agnatic succession gives priority to—or limits inheritance of—a throne or fief to male heirs descended from the original title holder only through males. Traditionally, this system determined the names and membership of European dynasties. Until after World War II, the main forms of dynastic succession in Europe, Asia, and parts of Africa were male-preference primogeniture, agnatic primogeniture, or agnatic seniority.

The agnatic model, also called Salic law, completely barred women from inheriting thrones and restricted succession to thrones and land to men in parts of medieval and later Europe. This strict agnatic inheritance has been officially dropped in all existing European monarchies except Liechtenstein. By the 21st century, most ongoing European monarchies had switched to absolute primogeniture, where the monarch’s first child inherits the throne regardless of sex.

Genetic genealogy

Because human Y-chromosome DNA (Y-DNA) is passed from father to son, genetic analysis can trace patrilines and agnatic kinships among men. Y-chromosomal Adam (Y-MRCA) is the most recent common ancestor from whom all living men’s Y-DNA descends through the male line. In 2012, the discovery of a rare, previously unknown Y-chromosome variant led researchers to estimate that Y-chromosomal Adam lived about 230,000 years ago. Before that, estimates had placed him much more recently, within tens of thousands of years.