Some of you have heard the religious hokum about how Eve was created from one of Adam’s ribs – and some have had the misfortune of meeting idiots who actually believe that men have one less rib than women because of this. Prepared to get scienced.
Now, of course, this isn’t an attack on religion, it’s just another informative article. I only bring up the religious flipside to address a conceptually wrong idea – that somehow women came from men and men were “here first”. This couldn’t be farther off the mark because, as the title reveals, all men were once women.
Let me explain. For those of you who don’t know how human gender is determined, it’s based on what’s known as the XY sex-determination system. This system applies not only to humans, but most mammals, some insects and some plants. To put it simply, women have two of the same sex chromosomes (XX) whereas men have two distinct sex chromosomes (XY).
Here’s the crux of the matter – as an embryo, everyone is “female” until the Y chromosome kicks in about 6-8 weeks after conception. Technically speaking, the embryo is undifferentiated (though it takes chromosomes from the mother and father to make the pair), but I’m addressing the conceptual flaw of “men came first” here, not the medical technicalities. The thing is, the Y is the only thing that determines whether the embryo becomes a male, therefore the “default” will be the only other option: female. Abnormal embryos with XXXY will still be male because of the Y, so we can see that the X is not a determining factor, and is thus the “default” case. My medicine student friend pointed out to me that the embryo isn’t considered female (because it already has XX or XY), which is why I put “female” in quotation marks. Remember, this is a conceptual issue – if one were to say “men came before women” they would be more correct to say “women came before men”, though medically they would both be technically wrong (the embryo is often referred to as a proto-female; I’m just saying that it’s more female than male, not that it’s definitely female). That’s also why males have nipples, which pretty much serve no purpose. Also, some of you may know that the female clitoris and male penis grow from the same genital tubercle when in embryo form (by the way, both enlarge when aroused). The tubercle is undifferentiated – the only thing determining whether it turns into a penis or clitoris is exposure to testosterone. Medically, the clitoris is said to be the homologue of the penis (the female counterpart of the penis). Some have oversimplified this by saying “the clit is just an under-developed penis”. Well, now that we know all men were once women, it’s more accurate to say the penis is just an oversized clit.
So the truth is, all men were once women, and thus all men come from women (not the other way around!).
Now before the guys go off with their tails between their legs, and the girls float off with their big heads, I wanted to point out that this fact has another implication. Women often call men “primitive”, but in reality, women are actually the baser form. In fact, studies have shown that the male Y chromosome is evolving much faster than the rest of the human genetic code.
“The Y chromosome appears to be the most rapidly evolving of the human chromosomes,” said study co-author Dr. David Page, director of the prestigious Whitehead Institute in Cambridge and a professor of biology at MIT. “It’s an almost ongoing churning of gene reconstruction. It’s like a house that’s constantly being rebuilt.”
But make sure to take this information in context! This doesn’t necessarily mean that men are the more evolved sex, since the Y chromosome only determines a person’s sex. However, the Y chromosome is undoubtedly special. Unlike the other 44 chromosomes, it is an individual and not part of a pair, and it is also an “evolutionary powerhouse”. Scientists are expectant of future discoveries regarding the Y chromosome as it shows so much potential (in multiple areas, not just determining sex).
Post time 5-1-2015 12:35 PM
变色卡
