Double translocation heterozygosity and normal fertility in domestic sheep

摘要

Intermating of sheep heterozygous for what was believed previously to be two different submetacentric translocations (Massey I and Massey III) and subsequent meiotic studies on one of the ram progeny have confirmed that these translocations are completely nonhomologous. A ram heterozygous for the two translocations, when mated to ewes of normal karyotype, produced an above-normal number of progeny. During mating there was no undue return to service. The fertility of double translocation heterozygous ewes was also normal. An hypothesis is suggested to explain the odd anomalies of fertility that have been described in sheep and humans carrying Robertsonian translocations.