Why Your Penis Doesn’t Have Spikes On It

A heterosexual couple trying to copulate with a spiky male member would be painful enough, but don’t even force me to have a mental picture of two men going at it when one of them as a thorned wang. Ugh, too late. But while others in the animal kingdom have horny penises, humans do not. How come?

Stanford University believe it’s “the loss of a particular chunk of non-coding DNA” in humans that left our spikes behind.

It has long been believed that humans evolved smooth penises as a result of adopting a more monogamous reproductive strategy than their early human ancestors. Those ancestors may have used penile spines to remove the sperm of competitors when they mated with females. However, exactly how this change came about is not known. The researchers did not set out to study penile spines. Rather, they were looking for chunks of DNA that had been lost from the human genome but not the chimp genome, so they could then try to pinpoint what those chunks did. The approach differs from that in most studies, explain Bejerano and Kingsley, in looking at what has been deleted from the human genome rather than what is present. “In the case of our study, had you started from the human genome, there would be nothing there to see,” says Bejerano.

They first systematically identified 510 DNA sequences missing in humans and present in chimps, finding that those sequences were almost exclusively from the non-coding regions of the genome, between genes. They then homed in on two sequences whose absence in humans they thought might be interesting — one from near the androgen receptor (AR) gene and one from near a gene involved in tumour suppression (GADD45G).

Inserting the chimpanzee sequences into mouse embryos revealed that the former sequence produced both the hard penile spines and sensory whiskers present in some animals. The latter sequence acted as a kind of brake on the growth of specific brain regions — with the removal of its function appearing to have paved the way for the evolution of the larger human brain. “The goal of the project was to find molecular lesions [losses] that underlie human evolutionary traits, with the examples illustrating different aspects of the principle,” says Kingsley. “Until we looked at where the DNA was expressed, we had no idea which switch — if any — it would actually control,” adds Bejerano.

As for why your penis might bend to the left, or curve downwards, or rotate ninety degrees counter-clockwise when erect? I think god just wanted us to have more variety :)

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  • Jim Hlavac

    So, they can find the DNA and the reason and the what have you of spiked penises — but they can’t find a natural born gay guy at a 100 yards or the reason for him? Oh, I don’t think they’re looking then. Still, if they do worry so much about us, and wish to cure us, they’re going to have to figure out a ‘why’ first. Because condemning us into nonexistence seems not to be working. They’re going to need scientific help; perhaps when these guys are done looking at the cucumbers in their pants they can assist. But I’m sure the geniuses at NO GAYS, Inc, will soon accuse us of having spikes down there (instead of say, Jewish horns or something) and then will demand we castrate ourselves so nothing more can come of it. Or am I just being um, ornery this morning? Hmm.

  • divkid

    im confused (and too lazy to click on link)…are they saying a chimp chubby still DOES have spurs?

    if so, then how does that fit with the hypothesis: that humans traded spiky schlong for monogamy? because chimps are waaay more promiscuous, which has been equated to the larger size of their testicles.

    and what of bonobos!? and what they get up to!–surely not with spiky dicks?!!! *gasps*
    if so, then no wonder the chimps have got such nasty looking purple asses!

  • Devon

    Speak for yourself.

  • divkid

    spikes, hmm, not sure;
    but i *have* encountered the dreaded NEEDLE DICK!

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