Abstract
Michel Georges presented the results of his research into de novo germline mutations in cattle. It has recently become possible to directly estimate the de novo germline mutation rate by sequencing the whole genome of sire-mother-progeny trios. In these studies, mutations are generally defined as heterozygous variants in offspring but absent in both parents. They are assumed to have occurred in the germline of one of the parents and to have been transmitted to the offspring via sperm or oocyte. This definition assumes that detectable mosaicism in the parent in which the mutation occurred is negligible. However, as Mr. Georges has shown us, in cattle, 30 % to 50 % of de novo mutations present in a gamete can occur during the first cleavage cell divisions in males and females respectively, resulting in frequent detectable mosaicism and a high rate of sharing of multiple de novo mutations between siblings.
