Re: Genetic Study Shows Snake Evolution

[Jeff Hecht <jeff@jeffhecht.com>]

At 11:05 AM -0800 2/4/04, Morgan Churchill wrote:
> I read the article, then the abstract.  If snakes aren't related to 
> monitors, then what group did they find them closely related to?  I 
> saw no mention of any probable ancestor group, which makes me kind 
> of suspicious of this.
They were trying to rule out the link between monitors and snakes, 
but didn't get firm rooting of where snakes should go. Here's a 
statement frm their paper:

"Our results (figure 1) show that Varanus is allied with
the remaining anguimorph lizards (Helodermatidae,
Xenosauridae and Anguidae) to the exclusion of snakes
(support values for the ML, MP, ME and Bayesian analy-ses
are 98, 95, 98 and 100, respectively). Our phylogeny
also rejects the association of snakes and amphisbaenians
(support values of 95, 85, 79 and 100). The clustering
of snakes with iguanian lizards (figure 1) is not strongly
supported, but is curious because of their presumed
Gondwanan ancestry and some shared similarities of the
chromosomes, skull, vertebral column, inner ear, urinary
bladder (absence) and oral glands (Bellairs & Underwood
1950; Rieppel 1988)." -- Jeff Hecht