2008-12-21

Parthogenesis before christmas


A friend at work recently gave me a couple of Extatosoma tiaratum eggs, which in plain english is a stick insect. The cool thing with stick insects is their reproductive behaviour, which has bended the rules that we might think ought to be universal. When the females have males around, they mate in the good old fashion lutheranian way, i.e. female get's down with male and have babies. Not very exiting. But when there's no suitable male in her territory, she's able to do what no human ever has or ever will be able to do; namely, to make babies herself. This is
known as parthogenesis, in which an egg continues to develop into a embryo and then you know the story... In short, no male gamete is needed! That seems to be a very flexible system.

Parthogenesis is not that uncommon. It's known to occur in insects and arthropods, and also in some reptiles, fish, birds and sharks. Since it's a egg that develops into the offspring, the offpring will be all female if the sex chromosome system is two like chromosomes determine the female sex (like our XY-system), or they will be all males if two like chromosomes determine the male sex (like the ZW-system in moths). The offpring will be able to reproduce in the same way as it's mother, or - if it's female - continue with the self-copying.

What makes parthogenesis even more cool than cloning is that here, all cellular material is of the same descendant, whereas in cloning, only the nucleus will be identical to it's "mother". So, once again; an example of the amazing world of nature. We can try to mimc and to understand but we will never ever be able to comprehend it all. And that's not necessary a bad thing.

(I actually had a dream once where parthogenesis was proven to occur in a deer. I didn't realize that it was a dream until I started talking about the subject with my fellow biology students, who started to laugh at my story. If they didn't laugh, then maybe I'd still believe that parthogenesis could occur in mammals. I mean, just count the number of individuals who believe that a 13 year old girl, who lived about 2000 years ago, gave birth to a kiddie without the help of a penis. At least I saw some empiric proof in my very, very realistic dream, *harr harr*.)

1 kommentar:

Anonym sa...

Coolt! Jag undrar hur det fungerar...

/jenny