The relationship between single parent and parent pair genetic likelihoods in genealogy reconstruction

Abstract

In the present paper, techniques of genealogy reconstruction based on genetic likelihoods of parent-offspring relationships are explored. Previous applications of such techniques have involved human populations, with emphasis placed on identification of parent pairs followed by reconstruction of families. In natural populations, this approach is neither practical nor necessarily a realistic representation of population structure. It is proposed that for natural populations emphasis should be placed first on locating the most likely mothers and fathers for a given individual, then seeking the most likely pair among that subset of genetically possible parents. Thus the genealogy is ultimately represented as a set of genotype triplets consisting of each individual coupled with its mother and father. Mathematical analyses show a strong positive correlation between single parent and parent pair likelihoods within triplets; this result is corroborated by statistical investigation of data from a natural plant population. Therefore the practice of constructing parent pairs using only likely single parents is justifiable on statistical grounds.