Only a few molecules separate you from having sensory whiskers and a penis spine. That's right - evolution has cheated you out of those whiskers that make your cat a super-sensor and the spines that, well, make your penis super-sensitive. A study published today in Nature reveals that human DNA still bears traces of genes that could, if tinkered with slightly, cause the next generation of Homo sapiens to have new sensory organs. And penis spines. How would that work?
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The researchers who conducted this study wanted to know whether there were any obvious spots on the human genome that could explain why we are so different from our chimp cousins, whose genomes are so similar to ours. After a lot of analysis, they discovered that there are 510 spots on the human genome that look like chimp DNA - except with a few key deletions. And most of these deletions are in areas of "regulatory DNA," bits of the genome that can control other bits, often by turning genes on or off. You could say that our genome has deleted the switches that activate chimp-like traits.
And one of those deletions happens to be in an area where regulatory DNA once flipped a genetic switch that led to the growth of sensory whiskers and penis spines.
According to a release about the study:
[The] regulatory sequence [is] near the human androgen receptor gene, a molecular change linked to the human anatomical loss of sensory whiskers and keratinized penile spines. Penile spines are commonly found in other animals, including chimpanzees, macaques and mice, but a more simplified morphology tends to be associated with the monogamous behaviour of certain primates.
So why did we lose these awesome features in the first place?
Say the authors in their Nature paper:
Ablation of spines decreases tactile sensitivity and increases the duration of intromission, indicating their loss in the human lineage may be associated with the longer duration of copulation in our species relative to chimpanzees. This fits with an adaptive suite, including feminization of the male canine dentition, moderate-sized testes with low sperm motility, and concealed ovulation with permanently enlarged mammary glands, that suggests our ancestors evolved numerous morphological characteristics associated with pair- bonding and increased paternal care.
So spinelessness makes you less sensitive so you can have sex longer. It's actually a good evolutionary modification for people who live in pair bonds in a species with females who are in estrus all the time. OK, fine. But apparently we lost our sensory whiskers around the same time, because the development of the whiskers is closely tied to the development of penis spines (perhaps they should be called penis whiskers?).
The interesting question - which for some reason the scientists didn't want to answer - is whether we could use a gene therapy to replace that deleted regulatory DNA. Basically, we'd add an activation switch to the whisker/spine sequence, flip it to "full blast," and start growing new body parts. Being able to sense the world with whiskers, the way cats and mice do, would be pretty great. And I'm sure we'd find a use for those penis spines. Rule #34 you know.
Read more about the research paper in Nature.