Re: Mice given bat-like forelimbs through gene switch

[Gautam Majumdar <gmajumdar@freeuk.com>]

On Thursday 17 January 2008 01:48:14 Louis Bérubé wrote:
> Can someone please please repost it? I got it truncated.
>
> -Louis

Here is the abstreact

GENES & DEVELOPMENT 22:141-151, 2008
Regulatory divergence modifies limb length between mammals
Chris J. Cretekos1,2, Ying Wang1, Eric D. Green3, NISC Comparative Sequencing 
Program3, James F. Martin4, John J. Rasweiler IV5, and Richard R. 
Behringer1,6

Natural selection acts on variation within populations, resulting in modified 
organ morphology, physiology, and ultimately the formation of new species. 
Although variation in orthologous proteins can contribute to these 
modifications, differences in DNA sequences regulating gene expression may be 
a primary source of variation. We replaced a limb-specific transcriptional 
enhancer of the mouse Prx1 locus with the orthologous sequence from a bat. 
Prx1 expression directed by the bat enhancer results in elevated transcript 
levels in developing forelimb bones and forelimbs that are significantly 
longer than controls because of endochondral bone formation alterations. 
Surprisingly, deletion of the mouse Prx1 limb enhancer results in normal 
forelimb length and Prx1 expression, revealing regulatory redundancy. These 
findings suggest that mutations accumulating in pre-existing noncoding 
regulatory sequences within a population are a source of variation for the 
evolution of morphological differences between species and that 
cis-regulatory redundancy may facilitate accumulation of such mutations.

-- 
gautam