Re: Further Thoughts on the Origin of Chelonia

["David Marjanovic" <david.marjanovic@gmx.at>]

----- Original Message ----- 
From: "Tim Williams" <twilliams_alpha@hotmail.com>
Sent: Thursday, October 23, 2003 1:28 AM

> Also, even within a given clade, the same genes
> from different species can have their own intrinsic biases
> (e.g., codon usage, GC content), which can further mess things
> up, since these biases can be mistaken for synapomorphies.

Of course a shift in codon usage can itself be a (rather morphological)
synapomorphy; but this, too, stays undetected as long as codon usage is
unknown in the species in question, as it, I assume, usually is. Takes
experiments in gene expression to find out, right?