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Positive selection at the ASPM gene coincides with brain size enlargements in cetaceans

作者: 
徐士霞 陈远 程月凤 杨丹 周旭明 徐俊晓 周开亚 杨光
发表年度: 
2012
卷: 
279
期: 
1746
页码: 
4433-4440
摘要: 

The enlargement of cetacean brain size represents an enigmatic event in mammalian evolution, yet its genetic basis remains poorly explored. One candidate gene associated with brain size evolution is the abnormal spindle- like microcephaly associated (ASPM), as mutations in this gene cause severe reductions in the cortical size of humans. Here, we investigated the ASPM gene in representative cetacean lineages and previously published sequences from other mammals to test whether the expansion of the cetacean brain matched adaptive ASPM evolution patterns. Our analyses yielded significant evidence of positive selection on the ASPM gene during cetacean evolution, especially for the Odontoceti and Delphinoidea lineages. These molecular patterns were associated with two major events of relative brain size enlargement in odontocetes and delphinoids. It is of particular interest to find that positive selection was restricted to cetaceans and primates, two distant lineages both characterized by a massive expansion of brain size. This result is suggestive of convergent molecular evolution, although no site-specific convergence at the amino acid level was found.

刊物名称: 
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIE
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