Genetical Research

Research Article

Digenic descent measures for finite populations*

C. Clark Cockerhama1 and B. S. Weira1

a1 Department of Statistics, North Carolina State University, Raleigh, North Carolina 27607


The development of a set of two-locus descent measures is reviewed. The three digenic measures, inbreeding coefficient and parental and recombinant descent coefficients, are considered in detail. The derivations of these three in pedigrees, fixed mating systems, and random mating in monoecious or dioecious populations are given. General expressions for digenic frequencies and disequilibria functions at any time are found by applying the three digenic descent measures to two types of initial populations. The final or equilibrium status of the population is also given. As the inbreeding coefficient is the same as the recombinant descent coefficient in the case of complete linkage, avoidance or promotion of early inbreeding has similar effects on the two coefficients. Estimable components of linkage disequilibrium and other measures of association within and among populations are elaborated.

(Received March 01 1977)


* Paper No. 4112 of the Journal Series of the North Carolina Agricultural Experiment Station, Raleigh, North Carolina.