Thursday, April 12, 2007

The Ancient Virus World and Evolution of Cells: Part One, Intro

Hey how about a series of posts on some cool science, instead of clueless Creationists and megalomaniac Deniers? hehehe!

So we had a visiting professor come this week to give a few presentations-- Jim Van Etten was one of the first people to discover a Giant Virus (hes also a really great guy, even to a lowly pre-grad student like me). These guys are monstrous in viral and genome size, with some surpassing particle/genome size of organisms we would consider 'alive'! Giant viruses have turned the way we look at viruses upside down. 'De-evolved' creatures? Used to be bacteria, but lost the ability to reproduce on their own? Renegade bits of genome and protein?

hehehe Right. And histones dont do anything but neutralize DNA :P As our ability to identify and sequence new viruses increases, the hypothesis that viruses are ancient... maybe even ancestral to all life on earth... is starting to be taken seriously.

Humor me for a sec as I personify some inorganic molecules/viruses:
Okay, RNA world. Pool of neucleotides, proteins, enzymes and such, just floating around... Selfish bits of RNA protecting themselves with a protein coat could be what we call an RNA virus today. Then you could keep your RNA around longer if you stored it as a more stable DNA genome, with a little reverse transcriptase. Retrovirus? Still have a lot of mistakes with that, though, hmm-- How about keeping everything as DNA, all the time? Well there youve got a DNA virus.

But hey, this is science, not magic! We've got questions, we can use the scientific method to figure out answers (or get closer to some answers... or get more questions... but still, you go somewhere!). So Im going to go through a paper here that you all can get for free online:

The Ancient Virus World and Evolution of Cells

I picked this one in particular because Koonin is one of the Giant Virus dudes hehe Sweet.


Foxy said...

Related question, I think - how short is the shortest genome known? I mean, it seems to make sense that the earliest virii related 'things' would be the smallest possible molecules capable of reproducing themselves, yes? Is there anything on that level known of in modern times?

Does that make sense?

ERV said...

Hmm-- I think these guys are the latest 'smallest', but Im not sure what all they can do on their own.

The 160-kilobase genome of the bacterial endosymbiont Carsonella.

Giant virus genomes are twice that size!

Kristjan Wager said...

ERV, did you see this story in the Proceedings of the National Academy of Sciences?

Discovery and analysis of the first endogenous lentivirus

It's a couple fo weeks old, so I might have overlooked any psots you've made about it.