Dr Tatiana's Sex Advice to All Creation by Olivia Judson

Dr Tatiana's Sex Advice to All Creation by Olivia Judson

Author:Olivia Judson [Judson, Olivia]
Language: eng
Format: epub
Tags: Divulgación, Ciencias naturales
Publisher: ePubLibre
Published: 2002-01-01T05:00:00+00:00


Bad news: you’re finished. All you can do is stagger about on your eight stumpy legs in the hopes of finding a stray sister so you can mate once more before you die.

Life’s not fair. Not only have you had your day, but you’re not even really the scourge of the lesser mealworm beetle. That’s your sisters. You’re just an accessory to their crimes. Let me explain. The girls in your family suck eggs—the eggs of the lesser mealworm beetle, to be precise. When a mite sucks an egg, her belly swells up to twenty times its usual size and she becomes a huge balloon with a tiny head and legs—the mite version of a caricature of a grotesquely fat man. Her children—as many as fifty—develop and copulate inside her, then she bursts. The newly emerged female mites seek out any lesser mealworm beetles who have succeeded in hatching and stow away on the beetles’ undersides like so many tiny scabs. The female beetle unwittingly carries this deadly cargo with her when she goes to lay her eggs. (Can female mites distinguish between male and female beetles? I would guess they can, but nobody knows.) Meanwhile, you male mites rarely manage to leave your mother’s body—and die almost before you’ve lived.

Will you go to hell for having screwed your sisters? Don’t worry about that. Whether or not hell exists, incest is not intrinsically bad. If you could flick through Who’s Who in Nature, you’d find a multitude of organisms who, like you, habitually practice close incest without ill effect. True, it’s not advisable for everyone: among humans, for example, the children of brother-sister or father-daughter matings are likely to be sickly or deformed. But this is not divine retribution for monstrous sin. It’s a simple consequence of genetics.

Problems with incest are due to recessive genes. What’s a recessive gene? Elementary, dear mite. Humans and most other sexually reproducing organisms are “diploid”: they receive two copies of each gene, one from their mother and one from their father. If the two copies are different, how they interact to influence a trait, such as eye color, varies—but the outcome can be simple, with one copy overriding the other. The overriding copy is known as dominant, the overridden copy as recessive. Thus, the effects of a recessive gene don’t show unless an individual has inherited two copies of it. Such an inheritance can be deadly. Recessive genes are more likely not to work properly, so a double whack can be disastrous, resulting in immediate death or debilitating disease.

When a recessive gene is rare, however, it can persist unseen because most of the individuals who harbor it will have only one copy. Herein lies the danger of incest. Because family members are genetically more similar to one another than they are to strangers, sex in the family raises the odds of uniting two copies of a harmful recessive gene. The closer the kinship of the lovers, the more genes they will have in common—and the greater the risk that harmful recessives will be expressed in their children.



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