Friday, September 01, 2006

An RNA gene expressed during cortical development evolved rapidly in humans -- Nature

Interesting article... results of a straightforward computational screen to find conserved elements with accelerated recent evolution and then a detailed focus on the biology of one of the regions found.

http://www.nature.com/nature/journal/vaop/ncurrent/abs/nature05113.html
An RNA gene expressed during cortical development evolved rapidly in humans
Nature advance online publication 16 August 2006
Katherine S. Pollard.... and David Haussler
The developmental and evolutionary mechanisms behind the emergence of human-specific brain features remain largely unknown. However, the recent ability to compare our genome to that of our closest relative, the chimpanzee, provides new avenues to link genetic and phenotypic changes in the evolution of the human brain. We devised a ranking of regions in the human genome that show significant evolutionary acceleration. Here we report that the most dramatic of these 'human accelerated regions', HAR1, is part of a novel RNA gene (HAR1F) that is expressed specifically in Cajal–Retzius neurons in the developing human neocortex from 7 to 19 gestational weeks......
Using alignments produced by MULTIZ (http://www.bx.psu.edu/miller_lab/), we identified
34,498 conserved regions of the chimpanzee genome that are >100 bp long
and >96% identical with mouse and rat. Each conserved region was evaluated
for acceleration in the human lineage using a likelihood ratio test .....

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