SEX BIASES IN THE MUTATION-RATE

Men have more germ-line cell divisions than women. Does this lean to a higher mutation rate in males? Most estimates of the proportion of mu tations originating In men come either from direct observation of dise ase-inducing mutations or from analysis of the relative rate of evolut ion of sex-linked and autosomal genes in primates. The latter mode of analysis has also been applied to other mammals, birds and flies. For unknown reasons this method produces contradictory results. A majority of estimates using the best direct methods in humans indicate a male bias for point mutations, but the variance in estimates is high. It is unclear how the evolutionary and direct data correspond and a consens us as to the extent of any male bias is not presently possible. While the number of germ-line cell divisions might contribute to differences this by no means accounts for all of the data.