Figure 6.
Possible consequences of X–Y recombination suppression: two major, parallel themes of Y Chromosome evolution. Summary of major events and processes in the evolution of the mammalian X and Y Chromosomes from a pair of autosomes. The initial step was the Y Chromosome's acquisition of the testis-determining gene, which was followed by suppression of crossing-over between the X and Y Chromosomes over most of their length. Lack of X–Y crossing-over resulted in a cascade of effects apparent within the sex chromosomes and genome-wide. The soma (bottom) and germline (top) influenced independent aspects of sex chromosome evolution.
