A boa's virgin birth

[Zuul]

Parthenogenesis has been observed in vertebrates before, but this one is a bit unique.

Sex chromosomes are packages of DNA that drive the development of sexual characteristics; they essentially make animals genetically male or genetically female.

Humans for example have X or Y sex chromosomes; females have two X chromosomes and males have a combination of an X and a Y chromosome.

In place of X and Y, snakes and many other reptiles have Z and W chromosomes.

In all snakes, ZZ produces males and ZW produces females.

Bizarrely, all the snakes in these litters were WW.

BBC story here.

A couple of interesting things learned from this: The female boa in question did have interactions with males, but didn't utilize any of their DNA in her eggs. She only produced her parthenogenetic clutches when she had been exposed to males, despite them not being the fathers. And before this, WW individuals were assumed to be non-viable.

[Rube E. Tewesday]

I love this kind of stuff. That nature can still surprise is glorious.

[Marsilia]

That is really, really cool.

[CatInASuit]

I guess she took a look at the local males and decided she could do a better job herself.

[Sir Richard ffoulkes]

Or the males decided her approach was unappealing, and they made her a suggestion, and she acted on it. But surely Zuul knows that "unique" is an absolute, and "a bit unique" is as valid as "slightly dead" or "rather pregnant".

[Peeta Mellark]

This is so great. I hope that they attempt to breed some of the WW offspring. I'd be very interested in finding out if they're fertile or not. If they are fertile, they'll only be able to have female offspring. Presumably, half of them would be normal females and half would be WW.

Or the males decided her approach was unappealing, and they made her a suggestion, and she acted on it.

Nice. I'm going to have to remember that one.

But surely Zuul knows that "unique" is an absolute, and "a bit unique" is as valid as "slightly dead" or "rather pregnant".

Actually, this is a common argument. When the word "unique" entered the English language in the 17th century it was as an absolute, as you describe. It then passed out of favor and ceased to be used as an English word. When it came back in from the French, it gained wider popularity with the meaning of "having a rare and unknowable occurance rate" or "special". None other than J.D. Salinger himself used it in a similar sense: "We were fairly unique, the sixty of us, in that there wasn't one good mixer in the bunch." It's one of those words that inspires bloodbaths between the prescriptivists and descriptivists. Since we don't know if WW snakes have hatched before or not, it would fall under the "special" definition instead of the "being the only one" definition.