Saturday, 23 December 2006

A story for the season

A female Komodo dragon (Varanus komodoensis) at London Zoo has produced a clutch of young without the assistance of a male*. That's right, we're talking virgin birth. Or, more accurately, parthenogenesis.

I'm not sure whether all the media attention is because mum belongs to the world's largest species of lizard or because of the felicitous timing of the event. Something about the dragon's new brood has caught the imagination. It can't all be down to a slow news week—not with the Ipswich serial killings, Shane Warne's retirement and the Victorian bushfires.

The Komodo dragon isn't the first species of monitor lizard (Varanidae) to be identified as reproducing in this way. Parthenogenesis has also been recorded in a captive Varanus panoptes, a large goanna from western and northern Australia. In fact, parthenogenesis isn't that unusual, even among vertebrates. But you never read headlines about parthenogenetic geckos, whiptail lizards, blind snakes, all sorts of fish ... and turkeys.

(Turkeys? How festive can you get? Parthenogenesis is common in the Beltsville small white, apparently.)

Parthenogenesis can take place in different ways—through dodgy cell division, hybridisation between species or under the influence of Wolbachia, a bacterium that lives inside cells. In the case of the dragons, unusual cell division gave rise to the next generation.

So are the offspring exactly the same as the mother? No. For a start, they're male ...

Every developmental biologist, gel jock and their companion animal has blogged on the genetics of the parthenogenetic Komodo dragons, so you can read more about the process at Scienceblogs. Here's what Pharyngula, Evolgen and Discovering Biology in a Digital World have to say on it.

Happy Komodomas.


*Another Komodo dragon recently did the same thing at Chester Zoo. 'Tis the season.


Anonymous said...

I think it bears repeating from the Pharyngula essay that the ma is heterogametic - which is how komodo lizzies do mas - and her progeny are homogametic (have to be with parthenogenesis) and…
So Babyjeesus was the offspring of a komodo dragon.
Or Babyjeesus was a woman.
Or a lot of other things, but not what the silly bible says.

I'm drunk and I don't believe in any of that god stuff.


And then the male offspring are supposed to have you know what with their mother! It says so in the Nature paper: "Parthenogenesis in wild Komodo dragons could be a colony founded by a single unfertilized female."