Platypus!

Tiassa

Tiassa

Let us not launch the boat ...
Valued Senior Member
Seattle's own Dear Science, one Mr. Jonathan Golob, advises that something cool just happened:

If you want to reconstruct how we evolutionarily came to have external testicles, nipples, separate opening for pee and poop–all things we have but the Platypus doesn’t–we could compare how a Platypus is put together, its genome, to our own. Our common ancestor probably lacked all these things. Likewise, the Platypus has been busy since departing our common ancestor, figuring out how do things we can’t–like make poison or see the world using only electricity. How’d that happen?

Well, we now have a draft of the Platypus genome. This’ll be fun.

Right off, the male Platypus has five X and five Y chromosomes. Huh? By comparison, every other male mammal has one X and one Y. One of the more pleasant observations is how similar we are to them. Over 80% of the genes in the Platypus strongly resemble those in humans or mice.

The remaining fifth is where all the fun actions occurs! Like what? The genes for chemical receptors, that make the nose work, are totally different. Genes for making eggs? Different from just about anything. The eggs are tiny and the baby Platypus hatches much earlier than is typical in egg-laying creatures. The baby then licks milk off the belly of the mother–remember, no nipples! If you wanted a snapshot of the evolution of mammals, that don’t lay eggs and nurse their young, this is pretty much it.

(Dear Science)
Click to expand...

I mean, come on. It's a platypus.

The paper, "Genome analysis of the platypus reveals unique signatures of evolution", was submitted for review in September and accepted in late March. It appears in the May 8, 2008 edition of Nature, and has more authors than I'm capable of listing.
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Notes:

Golob, Jonathan. "Platypus Genome!" dearScience. May 14, 2008. http://dearscience.org/2008/05/14/platypus-genome/

Warren, Wesley C. et al. "Genome analysis of the platypus reveals unique signatures of evolution". Nature. May 8, 2008. http://www.nature.com/nature/journal/v453/n7192/full/nature06936.html
 
Uhm but yea, the Platypus is a member of a very early branch off the mammal tree.
And it has probably been isolated for a considerable amount of time in a pretty particular environment.
I really don't know what this Jonathan dude is so mystified about.. :shrug:
Although I have to admit that monotreme evolution is pretty interesting :)
 
Mystified?

I don't think he's actually all that mystified. He gets off on this sort of stuff.
 
Tiassa said:
I don't think he's actually all that mystified. He gets off on this sort of stuff.
Click to expand...

LOL good for him. I think that sort of stuff is interesting as well.

Hmm.. but why did you make this thread ? Something you wanted to discuss, or just share ?
 
Well, it's a genome map of a platypus.

Mostly an FYI. Many people have a certain affection for the platypus, since it's such a strange animal. On the one hand, there's a genome map for the thing. To the other, it's apparently strange territory. I'm not particularly qualified to comment beyond recycling an old Robin Williams joke.

I mean, really: five X and five Y chromosomes? That really does sound like the old bit about God smoking a joint in Heaven and saying, "Hey, Darwin ...!"

Work with me, here.
 
Hmm I believe that in such systems the multiple sex chromosomes have their origin in exchange of genetic material with autosomes.
 
Can't remember exactly but I think their conclusion was that the multiple XY chromos represented a series of duplications joint with informational reduction on the Y partner. I think they speculated the other XYs would eventually become autosomes as the factorial impetus of sex determination would be preserved on the final, reduced XY in the series. No mention as to possible multivariate associations among the units, so I think segregation was unique to each set. Otherwise you'd have a complicated dosage scenario, to say the least.
 
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