Patriliny, also known as themale line, thespear side^[1] oragnatic kinship, is a commonkinship system in which an individual's family membership derives from and is recorded through their father's lineage. It generally involves the inheritance of property, rights, names, or titles by persons related through male kin. This is sometimes distinguished fromcognate^[2] kinship, through the mother's lineage, also called the spindle side or the distaff side.

A patriline ("father line") is a person's father, and additional ancestors, as traced only through males.

In theBible, family and tribal membership appears to be transmitted through the father. For example, a person is considered to be apriest orLevite, if his father is a priest or Levite, and the members of all theTwelve Tribes are calledIsraelites because their father is Israel (Jacob).

In the first lines of theNew Testament, the descent ofJesus Christ fromKing David is counted through the male lineage.

Patrilineal or agnatic succession gives priority to or restricts inheritance of athrone orfief to male heirs descended from the original title holder through males only. Traditionally, agnatic succession is applied in determining the names and membership of Europeandynasties. The prevalent forms ofdynastic succession in Europe, Asia and parts of Africa weremale-preference primogeniture,agnatic primogeniture, oragnatic seniority until afterWorld War II. The agnatic succession model, also known asSalic law, meant the total exclusion of women as hereditary monarchs and restricted succession to thrones and inheritance of fiefs or land to men in parts of medieval and later Europe. This form of strict agnatic inheritance has been officially revoked in all extant European monarchies except thePrincipality of Liechtenstein.

By the 21st century, most ongoing European monarchies had replaced their traditional agnatic succession withabsolute primogeniture, meaning that the first child born to a monarch inherits the throne, regardless of the child's sex.

The fact that humanY-chromosome DNA (Y-DNA) is paternally inherited enables patrilines and agnatic kinships of men to be traced through genetic analysis.

Y-chromosomal Adam (Y-MRCA) is the patrilinealmost recent common ancestor from whom all Y-DNA in living men is descended. An identification of a very rare and previously unknown Y-chromosome variant in 2012 led researchers to estimate that Y-chromosomal Adam lived 338,000 years ago (237,000 to 581,000 years ago with95% confidence), judging frommolecular clock andgenetic marker studies.^[3] Before this discovery, estimates of the date when Y-chromosomal Adam lived were much more recent, estimated to be tens of thousands of years.

• Agnatic seniority
• Cadet branch
• Derbfine
• Family name
• Historical inheritance systems
• Hypodescent
• Hyperdescent
• Matrilineality
• Matriname
• Order of succession
• Patricide
• Patrilocal residence
• Primogeniture
• Royal and noble ranks
• Y chromosome