Single-parent segregant pools for allocation of markers to a specified chromosomal region in outcrossing species

Bulked co-segregant analysis is a method of rapidly allocating unmapped genetic markers to a specific chromosomal region. Although originally developed for utilization in populations derived from crosses between fully inbred lines, it has been proposed that co-segregant pools could also serve the.same purpose in outbreeding populations, if individuals from only a single large family are pooled. Large, fully mapped, single-sire backcross and half-sib families are presently available as part of the international chicken and bovine reference family panels respectively. In this study, power and tests of significance for single-parent co-segregant analysis are derived for full-sib, single-parent backcross and single-parent half-sib families, as a function of proportion of recombination between index marker and linked marker, proportion of single-parent alleles among the mates, number of individuals in each segregant pool and technical error variance. Power was found to be greater than 0·80 for many reasonable parameter combinations. The method is illustrated using microsatellite markers and a large single-sire bovine family, part of the international bovine reference family panel.