Bad science; bad conclusions


In the letter Peter Scholz wrote, published on July 22, Scholz stated: “nor is there any objective scientific evidence for a “gay gene” (the concept itself is illogical because homosexuals normally do not reproduce, and so their genes would not be passed on.)”

I’ll leave aside the “gay gene” material, as that is still very much a subject for debate in the scientific community, and simply point out that Mr. Scholz is the unfortunate victim of the idea of a little knowledge being a dangerous thing.

Mr. Scholz is indeed correct that if a genetic trait is not passed on to descendants, it will disappear when the person having the trait dies. That’s Biology 101. However, he has rather unfortunately overlooked Biology 102, the next lesson in which the student learns about “dominant” and “recessive” traits.

Put simply, a recessive genetic trait means people can carry the genes for something but not express it. A classic example is Tay-Sachs Disease. If you have the recessive gene responsible for it, it doesn’t mean you have it. If you have children with someone who doesn’t have the gene at all, your children won’t have it either, but some of them will inherit the gene from you.

However, if your mate does carry the gene, then there’s a 25 per cent chance that one of your children will have Tay-Sachs, a 25 per cent chance they won’t inherit the Tay-Sachs genes at all, and a 50 per cent chance they will be like you and your mate: carrying the genes but not having the disease, but capable of passing it on to their children, who themselves may or may not express it – and so on.

This example is particularly relevant because Tay-Sachs is an incurable condition. The longest you can expect a child to live who is born with it is to age five. According to Mr. Scholz’s simplistic explanation of genetics, this should means that there should be no children who ever have Tay-Sachs. After all, the ones who suffer from it would die well before they’d ever get the chance to reproduce. And yet real life people in some populations are strongly encouraged to be tested prior to having children.

So yes, Mr. Scholz, even if there is a “gay gene” or a combination of genes that would result in a homosexual preference, it’s entirely possible for it to be expressed in a population even if homosexuals don’t have children. So long as homosexuals have brothers and sisters and cousins and other blood relatives, some of that genetic material gets passsed on. Again, this has nothing to do with the argument over whether there is a genetic factor, only that ridiculously simplistic arguments that there can’t be are wrong.

Anyone who has a background with some kind of biology training should know this. Gregor Mendel published the paper describing how this worked (although he didn’t know about DNA or why it worked) in 1866. One would presume this would be sufficient lead time for someone interested in how such a thing is possible to find out for themselves. And I know Mendel’s pea experiment, which showed this, is part of practically every high school biology textbook, so someone graduating high school and-or university, who has taken a biology course, has no reason not to know it.

Unless, of course, they follow the age-old dictum of only learning enough to support their own biases.

Keith Morrison
Cambridge Bay

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