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Re: Mice "given" bat-like limbs; bet they want to give them back



I gave up cheap shots for the New Year so I will pass by Dann's humorous 
question re interspecific behavior standards; hmmm, spiders eat their mates, 
pigs eat their own young, cows defecate anywhere ... damn, there goes another 
New Year's resolution. Anyway, half my genome consisting of "retrovirus corpses 
in various stages of decay" would explain a lot. Makes the old "your ancestor 
was a monkey" insult look like small potatoes.

As David points out, lateral transfer may be way more important than anyone 
currently accepts. By logic, many of these events are benign or beneficial, but 
some might be catastrophic, species level or above. Surely many speculations or 
hypotheses have been advanced that attempt to tie the probability of a 
catastrophic event to average species lifespan; does anyone know of one that is 
testable?

Don

----- Original Message ----
From: David Marjanovic <david.marjanovic@gmx.at>
To: DML <dinosaur@usc.edu>
Sent: Saturday, January 19, 2008 6:20:44 AM
Subject: Re: Mice given bat-like forelimbs through gene switch

> Retroviruses are be able to combine the DNA of different species. In
 fact,
> endogenous retrovirus sequences have become a permanent part of the
 human
> genome. Up to 8% of our genes once belonged to other species.
> http://en.wikipedia.org/wiki/Endogenous_retrovirus

If you count all the retrotransposons and the formerly transposable
 elements 
(like LINEs and SINEs) as retrovirus material, over half (53 % or so)
 of our 
genome consists of retrovirus corpses in various stages of decay...

> Bacteria are able to exchange gene sequences not just between
 different 
> members
> of the same species, but between different bacterial species.

Not only. Don't you remember the famous photo of a hamster cell and two
 
bacterial cells doing it?

That must be why vertebrates share some genes with bacteria but with
 nothing 
else... and why the bacterium *Mycoplasma genitalium* contains genes
 for the 
synthesis of cholesterol, something otherwise limited to eukaryotes...
 never 
mind all the genes spread across (hyper)thermophilic bacteria and
 archaea 
alike...

In fact, what is a bacterial "species" or an archaeal "one"? Most
 species 
concepts are simply not applicable, and the rest needs arbitrary cutoff
 
points (% similarity in genome sequence, % similarity in AT content).
 It 
would make a lot more sense to just talk about clades.