Coefficient of relationship

Measure of biological relationship between individuals The coefficient of relationship is a measure of the degree of consanguinity (or biological relationship) between two individuals. The term coefficient of relationship was defined by Sewall Wright in 1922, and was derived from his definition of the coefficient of inbreeding of 1921. The measure is most commonly used in genetics and genealogy. A coefficient of inbreeding can be calculated for an individual, and is typically one-half the coefficient of relationship between the parents. In general, the higher the level of inbreeding the closer the coefficient of relationship between the parents approaches a value of 1, expressed as a percentage, and approaches a value of 0 for individuals with arbitrarily remote common ancestors. Coefficient of relationship The coefficient of relationship r {\textstyle r} between two people B and C is obtained by a summation of coefficients calculated for every line by which they are connected to their common ancestors. Each such line connects the two people via a common ancestor, passing through no person who is not a common ancestor more than once. A path coefficient between an ancestor A and an