coefficient of inbreeding The probability that two allelic genes forming a zygote are both descended from a gene found in an ancestor common to both parents. It is also used for the proportion of loci at which an individual is homozygous. The coefficient of consanguinity of an individual is the probability that two homologous genes drawn at random, one from each of the two parents, will be identical, and therefore homozygous in an offspring. The term is sometimes known as Wright's inbreeding coefficient (F), after the geneticist Sewall Wright who formulated it. F = ½ for a selfed mating; ¼ for full-sib mating; ⅛ for uncle × niece and aunt × nephew, or double first cousins (i.e. cousins by both parents); and 1/16 for first cousins.

coefficient of inbreeding The probability that two allelic genes forming a zygote are both descended from a gene found in an ancestor common to both parents. It is also used for the proportion of loci at which an individual is homozygous. The coefficient of consanguinity of an individual is the probability that two homologous genes drawn at random, one from each of the two parents, will be identical, and therefore homozygous in an offspring. The term is sometimes known as Wright's inbreeding coefficient (F), after the geneticist Sewall Wright who formulated it. F = ½ for a selfed mating; ¼ for fullsib mating; 1/8 for uncle × niece and aunt × nephew, or double first cousins (i.e. cousins by both parents); and 1/16 for first cousins.