GAMETOGENESIS PROCESSES AND MULTILOCUS GENE IDENTITY BY DESCENT

With few exceptions, the determination of unconditional probability of genes shared identical by descent (IBD) by relatives can be very diff icult, especially if the relationship is complex or if multiple loci a re involved. It is particularly difficult if one needs the IBD probabi lity in a explicit form, expressed in terms of interlocus recombinatio n fractions. In this paper, I will further extend the concept of gamet ogenesis process introduced elsewhere and indicate that it completely determines the gene IBD events of interest in pedigrees. I will demons trate that the gametogenesis process not only serves as a convenient c onceptual framework in considering IBD events in pedigrees bur also pr ovides a simple yet powerful tool to solve a wide range of seemingly d ifficult problems. In particular, I consider the problem of multilocus IBD probability for relative pairs, k siblings, and a group of pedigr ee members. In addition, I consider the problem of multilocus autozygo sity probability and the problem of gene preservation in close relativ es.