Fig. 3.

Ages and divergence of sex chromosomes in 24 species. The figure displays sex chromosome information of various species in order of their ages, from the oldest to the youngest ones, demonstrating that the degree of sex chromosome differentiation does not solely depend on time after emergence. Dark and light colors represent the recombination suppression regions and the PARs, respectively. Colors of filled circles corresponding to each taxonomic group are shown in the top left. Chromosome sizes were estimated based on cytological or sequencing data in the individual references. Chr, chromosome; my, million years.