Wednesday, November 02, 2011

The Advantages of Sex

I was browsing through Facebook this morning when I ran across a link my acquaintance Shawna posted to this very interesting article from the BBC: Worms' Sex Life Yields Advantage Over Parasites. It contains this wonderful line: "Sex has long troubled evolutionary biologists."

It troubles many of us, whether we're looking for it or trying to avoid it. But the reason it troubles these highly educated scientists, according to the article, is that asexual reproduction makes more sense ... an organism that clones itself doesn't need to waste time finding and seducing a mate, fighting off rival suitors, or running the risk of picking up a sexually transmitted disease. In addition to all that, an organism that has survived long enough to reproduce probably has a good genetic makeup that would be risked by dilution with genes from another organism that might be less desirable.

It's doubtful that asexual reproduction was a topic any of us thought about while we were trying to pick up that hot girl or guy at the dance. The horizontal tango ... which, as the saying goes, takes two ... was more likely to be on our minds.

You could read the entire study about why we don't reproduce on our own ("Running with the Red Queen: Host-Parasite Coevolution Selects for Biparental Sex") in the journal Science. Here's the abstract:

"Most organisms reproduce through outcrossing, even though it comes with substantial costs. The Red Queen hypothesis proposes that selection from coevolving pathogens facilitates the persistence of outcrossing despite these costs. We used experimental coevolution to test the Red Queen hypothesis and found that coevolution with a bacterial pathogen resulted in significantly more outcrossing in mixed mating experimental populations of the nematode Caenorhabditis elegans. Furthermore, we found that coevolution with the pathogen rapidly drove obligately selfing populations to extinction, whereas outcrossing populations persisted through reciprocal coevolution. Thus, consistent with the Red Queen hypothesis, coevolving pathogens can select for biparental sex."

Alternatively, you could just read the BBC article, which is more fun and understandable. The bottom line of the theory is that sex with a partner provides an evolutionary advantage by allowing organisms to vary their genetic structure enough with each generation to stay ahead of parasites that would otherwise evolve to cause nasty, if not fatal, diseases. I won't bore you with the details of the sex lives of worms that are detailed in the BBC article and the larger study ... especially not before breakfast.

So ...

It may be that you are drawn to coaxing that desirable partner into bed not because she's hot or he's a real stud, but because ... deep down inside ... you know that obligately selfing is not good for your genetic future.

Don't thank me ... it's all part of my quest to help you understand the world around you.

Good sex may not help you avoid all parasites ... such as Republicans and Democrats ... but it can give you something to do while they're busy screwing up the country.

Have a good day. Choose wisely. More thoughts tomorrow.



Amanda said...

Well this is the first time I'm thinking about asexual worms and how they managed to reproduce....

Mike said...

Is obligately selfing the only kind of selfing?

Margaret (Peggy or Peg too) said...

You and Mike read some of the strangest things. I thank you for that so I don't have to. :-)

eViL pOp TaRt said...

This is new -- I thought that worms do reproduce asexually; but maybe it's only some kinds, like earthworms (lumbricus) or flatworms (planaria). Both of those species can regenerate missing parts.

It's kind of neat that a species may have both the asexual and sexual means of reproduction: together they provide some evolutionary advantages in different ways.

Anonymous said...

It must take a pretty thick biologist to have to seek out the advantages of sexual reproduction.

Elvis Wearing a Bra on His Head said...

Obligately selfing sounds like something the Fundamentalists would object to, like sex toys.