Origin of the Y Chromosome

Posted Posted in Genetics, News

By Marisa Sanchez, Molecular and Cellular Biology ‘15 The genomes of male and female mammals differ by one chromosome. The Y chromosome is only present in males, and is responsible for initiating the physiological and morphological differences between the sexes. This has not always been the case though; at one point, the X and Y were identical, and over time the Y chromosome began to differentiate from the X chromosome and shrink in size. The Y chromosome today only has 20 genes, whereas the X chromosome has over 1,000 genes.