Friday 23 February 2001

Pic of the day: OK, I'm doing something strange again, but what is it this time?

It's the male's fault!

It may have surprised some people. It sure didn't surprise me. And I can thank Jehovahs Witnesses for that. Now that's surprising.

I'm talking about some piece of research here in Norway, it was in the news a couple weeks ago. Some scientists had followed up children who were born with birth defects a generation ago: Cleft palate, unusual shape or number of fingers, toes or genitals, that kind of stuff. Now they looked at the children of these people again. Not very surprising, it turned out that some did not have children at all. (More than usual in the population.) And their children were more likely to have birth defects of varying degrees. And the children of the males with defects were more likely than the children of the females to have defects of their own. Like, around 5% to 3%.

Why would that be? Well, there should certainly be a few clues even for the layman.

***

For quite a while people have noticed that newborn children seem to look more like their fathers, and then over the years start to take more after the mother and her side of the family. This hints that the genes from the two parents are not brought to bear quite at the same time. It is no hard rule, but there is a clear tendency that way. Sociobiologists have (surprise surprise) assumed that this has developed as a way for fathers to know which children are their own, and so restrict the women's ability to choose one male to father their child and another to raise it. This may certainly be one effect of it. But the real reason could lie further into the beginning of our lives ...

When I was young, somehow every few years a member of the sect Jehovah's Witnesses found their way to our outlying farm. This way I got my raspberry-jam covered fingers on a book or two of theirs, which tried to explain how Darwinian evolution theory must be just plain wrong. They backed up their somewhat shaky arguments with small, out of context quotes from Scientific American, a magazine that would later be one of my favorites. (And which, I can assure you, would never willingly have aided these people in their quest to bend science under the rule of a literal and sometimes unusual interpretation of the Bible.)

The Witnesses are interesting people in their own right, and have stumbled upon some fascinating information. But what matters today is that they for some obscure reason kept writing about the trophoblast. What went through their minds to choose an example like that, I'll never know. To me it seems pretty nearly the worst example they could find.

***

We all start our lives as parasites. The feminists that refer to a fetus as "part of the woman's body" can never have known a pregnant woman. The little creature is a parasite, admittedly one that the female body is prepared for and that is really necessary for her genes to carry on. But technically, it is sooo a parasite! A zygote can even by mishap fall out of the oviduct and start to grow in nearby tissue, a life-threatening condition.

This is all due to a set of genes that are supplied from the father's side, and that switch on as soon as the little ball of cells start to differentiate. These genes create a mechanism that can attach to the uterine wall, burrow in and start to provide food and oxygen for the little parasite. This develops into the placenta. Contrary to what some may think, the mother does not make the placenta to nurture the new life within her. (Though she does sort of accomodate it, luckily for us all.) It is mainly created by the offspring, and mainly with paternal genes. The child and the placenta are both derived from the fertilized egg, but the placenta is even more dominated by paternal genes than the fetus is.

Basically, the further back we go, the more the father's genes dominate. This explains why there are so many miscarriages early in pregnancy: Male genes are notoriously of poorer quality.

"What!?" Yes indeed. You see, women have all their ova (egg cells) ready before they themselves are even born. Then one or two at a time, these cells leisurely wake up through the fertile years and set off for their uncertain fate, from one of the best protected places in a human body. In contrast, male testes contain stem cells that divide like mad, again and again and again, day and night from puberty onward. Needless to say, transcription errors are more common when a line of cells divide a thousand times more often. Males are the engine of mutation! PHEAR UZ! MWAHAHA! Eh. Anyway. That's how it works.

And this is the reason why women, on average, are more attracted to extremely symmetric men. As you know, our left and right side usually are so different that you can easily see when a photo has been mirrored. And if you create a whole picture from just the left half or just the right, the two of them will look like siblings but not necessarily twins. The more identical they are, the more attractive the male is to many women. (That does not mean they act on it, but statistically it does make a difference.) These men have genes that are particularly good at decoding the rest of the genes, including those from the mother. So their children are less likely to have birth defects, or even end as stillbirths or spontaneous abortions.

It all fits together, like science always does. Which is why the study did not surprise me at all ... except perhaps that I had expected the men to be even more prone to birth defects in the next generation. But of course there are other things that count than genes. Virus for instance, and toxins from food or industrial waste. Not everything that goes wrong in the world is caused by your man! Just disproportionately much. :)