Are Men Actually Going Extinct?
The words 'according to a study' can be used to justify any old garbage, and the average reader has seen enough bullshit 'studies' reported in the media to be suspicious about them all. Tim Byron investigates.
Recently, the news has come that it's close to the end for men like me.
"Professor Graves, one of Australia’s most influential scientists, believes that women will win the battle of the sexes – and in the most definitive way possible. She says that the inherent fragility of the male sex chromosome, the Y sex chromosome, means that men are sliding towards extinction," said the UK's Daily Mail on the 2nd of April.
Similarly, the website for Channel 9's National News, reporting a lecture given at the Australian Academy of Science, claimed that "evolutionary geneticist Jenny Graves says while the process is likely to happen within the next five million years it could have begun in some isolated groups..."Its very bad news for all the men here," she told her audience". Oh dear. One of the country's 'most influential scientists' says that I'm doomed. DOOMED. But I'm looking out the window of my office right now, and I see men walking past. They don't seem particularly close to extinction, do they?Professor Graves' idea that 'men are sliding towards extinction' has been taken out of context. For better or worse, the human race is unlikely to end up like the separatist wimmin-only feminist's paradise described in Germaine Greer's The Female Eunuch. So what gives? Why is Professor Graves saying such things?
Firstly, let's explain the territory here. Many of you probably learnt about chromosomes and stuff in high school biology, but the details are probably a bit sketchy a few years on. Living things like plants and animals are made of cells, and inside all those cells is DNA, which is a very complicated chemical structure which serves as a recipe or blueprint; the different combination of chemicals in DNA tell the cell exactly how and when to make other chemicals. Different species have DNA that looks a bit different (but not that different); if you look at a typical stretch of DNA, the DNA of a human looks 97-98% similar to that of a chimp.For example.
Anyway, DNA is gathered into 46 chromosomes in us humans. With those 46 chromosomes, you more or less randomly inherited 23 of them from your mum and 23 of them from your Dad. This means that you have two copies of most of the chromosomes. But there's one pair of chromosomes, the X chromosome, where, if you're female, you have two 'X' chromosomes. However, if you're male you have one 'X' chromosome, and one 'Y'. That is, if your Dad gave you his 'X' chromosome, you're female, and if your Dad gave you his 'Y' chromosome, you're male.However, if you look at how other animals end up male and female, like Professor Graves does, they don't necessarily have the same arrangements we humans have. Having a combination of X and Y chromosomes isn't necessary for turning animals into males and females. In some amphibians and reptiles, sex is determined not by genes, but by temperature; if a Nile crocodile embryo inside an egg experiences temperatures that are overly warm or cold, it'll end up female. But if the temperature's just right, it'll be male. Other animals, like birds, have a completely different set of chromosomes that determine sex. And marsupials (like kangaroos) and monotremes (like platypuses) do it differently to us placental mammals (like us, or like cats or cows). But most placental mammals have an X chromosome and a Y chromosome like we do.
The important thing about the Y chromosome, apart from its presence meaning you probably have testicles and a penis, is that it's quite small as far as chromosomes go. There's much less information in the Y chromosome—and so many fewer recipes for making proteins—than in most chromosomes. The thing is, if you look at the Y chromosomes of various placental mammals (as Professor Graves has done), it looks like, historically, the Y chromosome started off as a very minor variation on the X chromosome. However, Professor Graves argues that the Y chromosome is inherently unstable - unlike the other chromosomes (where you get one copy from each parents), you can only inherit one copy of it.
This means that, if one of your male ancestors lost a bit of his Y chromosome, there's no way of replacing it (in contrast, if one of your male ancestors lost a bit of any other chromosome, it wouldn't matter as much because your female ancestor probably still had most of that DNA). Over the millions of years, as your ancestors evolved from things that looked like shrews to things that looked like monkeys to things that looked like Nickelback to things that looked like actual humans, the Y chromosome had a whole bunch of bits and pieces get lost in the shuffle. And now, in us male humans, the Y chromosome really only has 50 genes - the bare essentials - left.
Professor Graves, in her talk, argued that bits and pieces of the Y chromosome would continue falling off at the same rate they had in the past. In this argument, the Y chromosome in us humans will just disappear completely! Her estimates of when this will happen range from the near future (125,000 years) to the reasonably near future (5 million years), when you define 'near future' as 'a time in the future that probably will not be experienced by even the great-great-great-great-great-grandchildren of anybody reading this' (evolution works so slowly that 125,000 years seems like a nanosecond to people who research evolution and genetics).
In any case, the idea that humans could lose their Y chromosome for good isn't a stupid idea. It could happen. After all, there are various species of rodents who have seemingly done away with the Y chromosome (as Graves details in a review article in the scientific journal Cell). The thing is, though, those rodents still end up as males and females. They still seem to do the whole business with the sex and the semen and the egg. Babies occur. So, if this were to happen to us humans, you probably wouldn't even know about it. Men will probably still like whatever stereotypically male things men end up liking in 5 million years, and so will women. Assuming we haven't entered some weird future science fiction world where we transfer our minds to the internet or mostly have sex with androids, it's safe to say that penises will continue to find their way into vaginas. It's just that the particular genetic thing that makes you male or female might be different.
It's odd, though, that the Daily Mail and Channel 9 have started going on about this now. Graves first made these arguments over a decade ago, and the usual suspects sensationalised all this research at the time. Of course, science moves on. And so a paper in Nature by Jennifer Hughes and colleagues came out in early 2012 that compared the Y chromosome of the Rhesus monkey to the human Y chromosome. Humans and Rhesus monkeys are very distantly related cousins; we last shared an ancestor about 25 million years ago. And so if you compare my Y chromosome to that of a Rhesus monkey, you'll get a sense of how much change has happened in that 25 million years.
The thing is, not much has actually changed in that 25 million years. There's only one gene missing in the human Y chromosome that was there in the Y chromosome of our common ancestor with Rhesus monkeys. Hughes and colleagues basically argue that this means that the bits of the Y chromosome left are the important ones. They haven't changed much in the last 25 million years, and probably won't change much in the future. So this probably means that the Y chromosome will continue to be the thing that makes you male. But who knows. Anything's possible.
Of course the Daily Mail don't actually care whether the Y chromosome will go the way of the dodo. They report research like this for the purpose of making it a conversation starter. Most readers don't care about the Y chromosome, really. Instead, they care about the 'battle of the sexes'; we humans like to divide ourselves into teams and then cheer on our own side. And men in general in Western society seem less man-like than they used to—what with the rise of men wearing pink shirts who listen to dance music and eat vegetables and brush their hair!—and some people get anxious about this. What if this trend continues?!? Ahem.
With this stuff in the back of their minds, the Daily Mail don't really care whether the article informs readers about science. What they really care about is whether people will read the article and say "hey, I saw in the Daily Mail that men are going extinct" to their colleagues at lunch time or to their friends on Facebook. People will say variants on "nah, men are awesome!" or "boo for women". If you search for the article on Twitter at the moment, people are posting a link to the Daily Mail article saying things like "We're all gonna die LOL" or "Hey guys, did you know we're an endangered species?" or "huh. best enjoy them while they last". For these people, the facts about Y chromosomes don't matter; instead, the act of posting the article of Twitter is an opportunity to make a joke, or to say something ironic or vaguely witty, about men. And so it goes.Anyway, if you like penises (whether your own, those of others, or both), don't fret. They're not going anywhere any time soon. The Y chromosome might fade away, but if it's replaced by something else, you probably wouldn't even notice the difference. Perhaps the most interesting thing about all this stuff is that it shows how few genetic differences there are between men and women. We humans have about 20,000 genes all up, and there's only 50 on the Y chromosome. Some of those 50 do have some fairly large effects, of course (the gene saying "make more testosterone!", for example), but we're much more similar than different. All that 'battle of the sexes' stuff is not a war between people so different that they could come from different planets. It's more like a family feud.
Tim Byron (@hillsonghoods)
(Tribal man image via Shutterstock)