The chimp Y chromosome has now been fully sequenced, and the results are astounding. A study in Nature reveals that the chimp Y chromosome is radically different than the human Y chromosome. The chimp’s Y chromosome has only two-thirds the number of distinct genes/gene families, and 47% of the protein coding regions compared to its human counterpart. Furthermore, more than 30% of the entire chimp Y chromosome has no counterpart in humans. Even those segments that do have counterparts in the human Y chromosome are often located in different regions of the chromosome.
One the lead researchers, David Page, told Nature News that “it looks like there’s been a dramatic renovation or reinvention of the Y chromosome in the chimpanzee and human lineages.”Of course, this reinvention has to be explained in terms of common descent, so they speculate that the chimp Y chromosome experienced a loss of DNA, while humans experienced a gain. The surprise of the scientists involved, however, demonstrates that this find is counter-intuitive to Darwinian expectations.