Came across an interesting article in Slate t’other day, addressing Larry Summer’s recent “scandal”. While the article makes me yawn over the actual scandal, there was one paragraph I found veeeeeery interestink:
So, what do we think? Is he factually correct? Is he interpreting the data in a meaningful way? Does it matter? Does this mean that gender differences are impossible to irradicate or that we need to find different techniques to achieve gender equality without gender indenticality? Are we really as different as humans and chimps?
And does this explain why my savage monkey of a husband can’t put away the cereal box?
All it shows really is that a 1% difference can have vastly different amounts of impact. After all, even a monkey can see that the difference between a man and a woman of the human species is vastly smaller than the difference between a female monkey and a female human.
In the end it all depends on which of the genes are different. They don’t all mean equally much. A whole lot of them don’t seem to mean a thing. And even every one man can be vastly more different from another man, than from another woman. Even (or especially?) when it comes to putting away cereal boxes.
As with all discussions of what genetics really means (and I am but a layman), let’s be very careful of exactly what is being said here.
Men and women have different body parts and other physical attributes. The gene sequences required to encode the differences are what makes men and women “genetically different”.
North European men and South African men also have different physical attributes, but not different actual body parts and organs. Humans are actually incredibly genetically similar compared to other species because of a bottleneck 70,000 years ago which may have left only 2000 people alive worldwide. In this sense, it is fair to say that the gene sequence between men of any ethnicity is more similar than that between a human with a penis and a human with breasts and a womb.
Now, male humans and male chimps also have different physical attiributes, but similar body parts. How are we to gauge whether the male chimp’s shorter legs, furry body and protruding face require a gene sequence which is more different than that required to produce a womb and breasts but none of those chimpy features? My guess would be that it does require more gene changes to turn the human male into a male chimp than a human male into a humn female, but I’m afraid I must leave that to those more erudite than myself. I hope I’ve framed the matter correctly, at least.
PLEASE do not eradicate gender differences. They are cute. And “identicality”, of gender or race or individual is a creepy sort of concept. If that’s what it takes to achieve equality what say we skip it?
Depends on how you look at it. Of course the X and Y chromosomes differ, since the Y is so much smaller. But let’s look at the difference between humans and chimps if we exclude those chromosomes. We still have the 1 - 2 % difference. And, every gene is not equivalent to every other gene (or genetic sequence, to be exact).
The other thing to keep in mind is that some genes are regulatory in nature-- ie, there purpose is to turn on (or off) other genes at certain times. These genes can have a profound affect on the organism, well beyond a gene that codes for just one protein.
So, the sex differences are there as a starting point in all mammals. It makes more sense to talk about the differences from that base. There might well be behavioral, or even cognitive related genes on the Y chromosome that aren’t on the X, but until we find them, it’s all just speculation.
Just to be clear, the bottleneck idea cannot be stated as a fact. It’s a hypothesis with some evidence to support it, but is not widely accepted as having been “proven”.
Possible, I suppose, but doubtful. The Y-chromosome in humans contains only about 26 genes or gene families. Of those, about 16 genes are related to simple cellular housekeeping, and 9 gene families are associated with sperm production. One gene has been identified as having anything to do with male anatomy: the SRY gene. There isn’t much room for Y-linked behavioral genes.
The X-chromosome, in contrast, contains over 1,000 genes, most of which code for phentoypic effects unrelated to female anatomy.
…
Given the differences in the number of genes present on the X-chromosome vs. the Y-chomosome, and considering the total number of genes in the human genome is between 20,000 and 25,000, the genetic difference between the sexes could be as high as 5%, if you look at gross numbers. However, there is more to phenotype than simply the number of genes present. Genetic regulation plays a huge role in determining which of those genes are actually turned on or off, and when, and, as such, tends to be more important than the mere number of genes in determining phenotype.
Well, to split hairs even further, I understand that the genetic bottleneck is a fact, ie. that humans are amazingly genetically homogenous as of 70,000 years ago: I agree that a numerical bottleneck is just the strongest proposed explanation for this, although 2000 individuals was only a lowest possible bound (hence the “may” in my post).
Child Pshycologists without knowing analyzed Chimp art and always got the sex right even if they didn’t know they were dealing with chimp art. So I guess there must be certain traits common to both species and sexes.
The genetic differences are probably more restricted to physical features and I doubt female chimps are genetically closer to female humans whom with we can have babies, than with male chimps.
OK, this may be a dumb question, because I think I know the answer (which would be, “yes, of course”) but I’m learning more and more on this board that what I think I know the answer to I often don’t. So I’ll just ask the silly question: Is the extra X or the Y chromosome the only genetic difference between men and women? If you showed a DNA expert all the chromosomes except that one, would she be able to tell you the gender of the sample provider? Do any of the genes on the Y chromosome “switch on” or “switch off” genes on the other chromosomes, making them indirectly different between the genders?
Yes, no, yes with the following qualification: the DNA itself is not altered by these modulators, only the relative frequency with which they are transcribed and translated into functional protein.
A couple of years back it occured to me that the percentage of genetic difference between human males and females was roughly equal to the percentage of genetic difference between humans and chimps of the same gender, but I never pursued the notion. Needless to say, I’m tickled to see that others have noticed the same thing.
Some random observations:
Some of you folks appear to be so committed to the idea of minimizing gender differences that you want to dismiss this outright. Well, deal with it.
Similarly, some want to ignore the fact that there just isn’t much difference between us and other critters. In fairness, this is a rather common attitude among humans, presumably innate. Whether other animals feel the same way about us, we won’t know until cats learn to talk.
The genetic gender difference is ameliorated somewhat by the fact that males possess an X chromosome, so the effective difference is less than the percentage difference. (Which is a shame since, after the past few years, I would gladly welcome our new simian overlords. . . .)
The issue is not the fact that females and males are genetically different. That’s pretty bloody obvious, isn’t it? The issue is in fact that any difference between male humans and female humans has traditionally been seized upon and been (inaccurately) interpreted in a sinister light: i.e., “Hmm, women’s brains weigh less than men’s. We all know what that means, don’t we? Chicks are stupider than guys. Oops, women’s cerebral cortex’s are relatively larger than men’s. Let’s scrap that idea.” And so on. There are implications here for how people want to interpret this chimp-human theory: is one of the sexes less evolved than the other? et cetera. There are whole libraries of completely (debunked) crap that have been written in the past 200 years about humans and their place in the evolutionary tree. We don’t have a track-record of reliability in interpretation of scientific facts, do we?
