Platypus, platypus, wherefore art thou platypus?

Shakespeare might object, but it seems an appropriate headline!




The platypus has always amazed me. The darn thing is a furry mammal, but lays eggs like a reptile; produces milk like a cow, but doesn't have teats or nipples, its young feeding through a glandular patch on its skin; males have poisonous venom in spurs on their hind legs; it has a bill like a duck; and it finds its prey using electricity. What a mixture! When biologists first discovered it, their colleagues back in Europe suspected it was some sort of scientific hoax. They took some convincing.





Now the platypus genome has been decoded, and it's as mystifying as the creature itself. Turns out that the platypus has about 2.2 million letters in its genetic code, about two-thirds as many as a human. It has 52 chromosomes, of which a full 10 determine its sex (humans need only two to do that). To quote just one example of how weird the genes are:

The genes relating to the platypus's eggs offer further insight. The embryos develop within the maternal uterus for 21 days before they are expelled in a thumbnail-sized leathery egg. After 11 days of incubation, the young hatchlings emerge with their organs not yet fully differentiated. Like marsupials, they finish developing while nursing. The platypus shares with other mammals four genes associated with the zona pellucida, a gel-like coating that facilitates fertilization of the egg. But it also has two matches for ZPAX genes that had previously been found only in birds, amphibians and fish. And it shares with the chicken a gene for a type of egg-yolk protein called a vitellogenin. That suggests that vitellogenins, which are found in birds and fish, predate the split from the sauropsids, although the platypus retains only one vitellogenin gene, whereas the chicken has three.

Fascinating! I'm no scientist, but stuff like this makes me wonder what on earth was going on in the Creator's mind. Was He having fun that day, tinkering?



Peter