Having a human-centric view of the world, we tend to think of the traits that make us distinct from our fellow primates in positive terms, focusing on the features we’ve gained, like our big brains. But human evolution has also meant the loss of some potentially useful features, like upper body strength. New traits can also arise from the loss of DNA. So, it was just a matter of time before someone tried to identify the DNA sequences our species has lost along its evolutionary past. A study that does just that appears in today’s issue of Science, describing DNA sequence losses implicated in bigger brains and the end of penis spines.
The logic behind the new work is very similar to that used in the identification of “human accelerated regions,” areas of the genome that have undergone unusually rapid changes since humans split off from our common ancestor with chimps. The researchers started by comparing the chimp, human, and macaque genomes to help identify areas that are missing in humans, but similar between the other two primates. This indicated that humans have lost about 34 million DNA bases since we diverged from the rest of the primates; that’s over one percent of the entire chimp genome.
And no, a penis spine is not a baculum. Many mammals have bumps on their penises that humans generallydo not. The belief is that they are their to pull out a competitors sperm although there is not great proof here. I wonder if Fordyce’s spots are the leftover remnants of the spines? The normal form of these sebaceous glands includes a hair follicle. In addition, these spots can be found around the lips on the face. Right where whiskers would go. Perhaps Hirsuties coronae glandis are similarly derived remnants.
In a mostly monogamous species the bumps aren’t as necessary because there is not the same level of ‘adultery.’ This all makes for great media coverage as this is all over the MSM. Although, wouldn’t it be cool to have whiskers? The penis spines would just be extra.
Of course, many sex toys are covered with bumps. I wonder if there could be some sort of biological ‘memory’ that makes that useful? Perhaps the bumps are gone but the nerve ending that respond to them – in cats, the spines on the male penis induce ovulation – are still there? Would bumpy dildos have any effect on the female reproductive cycle? Who do I apply to for that research grant?