Thursday, 14 April 2016

Gay Pride

The Daily Mail writes up an interesting study on that most fascinating of topics - if homosexuality is at least part-genetic, how come the gene doesn't die out? For some reason the headline says the research is "controversial" without anything in the article explaining why.

The gist of it appears to be this:

'The trend of female family members of homosexual men to have more offspring can help explain the persistence of homosexuality, if we also consider that those males who have such genes are not always homosexuals,' explained Chaladze.

In other words, there is one group of genes which has two effects: it can make some men gay (fewer children) but it makes women have more children and the two effects almost exactly cancel out. Makes sense to me. Plus there is the obvious advantage that children who have more childless uncles (and aunts) stand a better chance of surviving as there are more adults to look after them.

(The traditional way of explaining this correlation is the other way round - men are more likely to be gay the more older brothers (or siblings) they have, which suggests that it is learned behaviour rather than genetic, which seems a bit less likely to me).

Which segues nicely into this story (whence I nicked the post title):

This is the moment two male lions in an African safari park were captured on camera - apparently trying to mate.

The two adult lions were photographed becoming more than affectionate in the Lagoon area of the Kwando Concession in Botswana, southern Africa. Lawyer Nicole Cambré, who took the pictures during a safari trip, said she saw the two male lions 'mating' and was told by her guide that this behaviour had been evident for a week.

Quite possibly those lions are gay, quite common with many animals, they just don't appear to be that fussed.

But there is another explanation, which I saw on TV a while ago. Lions live and fight in small groups, and it tends to be the males who do most of the fighting.

So if one group realises that it has far fewer males than the other, it backs down and goes somewhere else. Some lions have developed a mutation whereby the females also grow manes, you can tell from close up that they are slightly smaller than the males, but apparently this deception works well enough at a distance.

Ergo, perhaps one of those lions is actually female.


Random said...

Of course, if it were an exclusive condition, then humanity would die out. It may also result in a homosexual person not having biological children but not necessarily, for example, social pressure, closeting, etc.

But genetics is not based not only on individuals but also on populations, and evolution is based on on populations and environments. Homosexuality is relatively rare compared with hetero, and most are hetero, with many people bi. In addition, it seems that the natural state, humans are polyamorous and that marriage of a single man and woman as an institution is acquired rather than natural. So a family's generic material gets passed on by other siblings if a homosexual family member doesn’t reproduce, just as with any other person who doesn't reproduce for whatever reason.

Obviously communities of people that do not reproduce themselves for whatever reason will die out unless they recruit successfully.

Bayard said...

"The trend of female family members of homosexual men to have more offspring can help explain the persistence of homosexuality, if we also consider that those males who have such genes are not always homosexuals,"

Isn't that Genetics 101, as they say in the US? A reproduction-stopping recessive gene survives because you need two copies of it for its effects to manifest.

MikeW said...

Re lions,

Shove your hand down between its legs and ask it to cough. Best wear your Nikes though!

Random above, completely agree. Human evolution is about a million years of small scale, often isolated tribal units. The homosexual has uncle/aunt relationship with all the children he or she sees each morning and supports to reproduction age. We learn more from biologists Mole Rat studies and bees than American hunts for a 'gay genes'.

So a wholey gay women,to take the most 'troublesome' example keeps avoiding pregnacy (but not forever?) and is able to develop those female hunter gatherer skills, while she is still young herself, that keep her 25% stake infants alive and well. A wholey gay man might well we good on the hunt keeping the men out in the field and away from the women they would rather be sleeping with!I'm sure the anthropologists have done all this? I doubt the economists have much of use to say :)

Bayard said...

"So a wholey gay women,to take the most 'troublesome' example"

Yes, it's odd that studies of homosexuality seem to concentrate on men, whereas there are plenty of species where successful males gather many females meaning that there are a large number of males who never get to reproduce and yet the species survives.

Curtis said...

there are a large number of males who never get to reproduce and yet the species survives

Unless the number of males dwindles to single figures the survival of the species is unlikely to be affected

Also, in the past, many rich gay men probably had kids biologically.

Mark Wadsworth said...

R: "evolution is based on on populations and environments."

Exactly, I did a whole mini series on this a few years ago.

B. there's that as well.

MW, yup.

B, there are more studies on gay men because a) there are more (openly) gay men than (open) lesbians and b) women's sexuality boundaries are a tad more fluid.

C, there's that too, but that does not explain why the % of gay people in a population is such a fixed ratio. Even in openly homophobic countries where it is a hanging offence i.e. Islamic countries.

Anonymous said...

Its a limited world view again. That the gene us why makes us who we are. In spite of all the scientific evidence contrary to that ideological world view. The religion here is interesting psychologically