Detecting Variation in the Rate of Molecular Evolution in Different Lineages of Mammals

Abstract

A major research topic within molecular evolution studies is to understand more about the causes of the molecular evolutionary patterns that are recorded within and between taxa. The amount of germ cell divisions in females and males causes the majority of mutations, during DNA replication, that impact molecular evolution. In an XX female and an XY male system of diploid animals, the autosomes come in duplicates, with one copy from the male and female parent. Because of this, the idea that evolution is driven by male mutations has become increasingly more likely. This paper looks at the different male-mutation rates and determines that the male-mutation rate is much higher than female-mutation rates. Ry/a to be approximately 2.2, which means that Ry is approximately -24.2. From software analysis, x was approximated to be about 0.5. And since x and Ry are known, Ry/x was determined to be -49. The results for this paper show the calculated Rx/a and Ry/a are similar to the results of another study, but they are unique in that they produced a relatively high negative number for the Ry/a, which was about -49. This provides evidence that the male-mutation rate is higher than the female-mutation rate. This is interesting because this suggests that, from the data, the mutation rate in males is the defining force in molecular evolution. And because the rate goes beyond the prescribed model, future models of molecular systems will need to consider the rate of male mutations, as well as clarifying this male-mutation rate and calculating the rate of mutation in other sex-determinant systems.