What genes are involved in adaptive phenotypic change? Are the same genes involved in similar adaptive changes in different lineages? How can we link adaptive phenotypic evolution to genomic evolution across phylogenies? These are some of the questions that we are addressing in diverse examples in primates, birds and other vertebrates, in relation to such traits as coloration, colour vision and brain size. Having previously focused on single locus examples we are increasingly adopting genomic approaches to these issues, using techniques such as transcriptome sequencing and gene capture second generation sequencing.
Microcephaly genes & brain evolution
In recent work published in Molecular Biology & Evolution we demonstrate an association between the molecular evolution of two genes with important roles in brain development and the evolution of brain size across apes and monkeys.
Microcephaly is a human developmental disorder which affects brain development. It is associated with a number of genes which have been previously shown to have interesting patterns of evolution in lineages leading to apes and humans. We collected data for 21 species of apes and monkeys for four microcephaly genes and showed that positive selection has shaped the evolution of these genes. Furthermore for two genes, called ASPM and CDK5RAP2, the rate of molecular evolution is positively associated with brain size. The association is stronger for neonatal brain size than adult brain size, suggesting a role in prenatal development that is consistent with a direct effect on neuronal proliferation and the evolution of brain size. You can read the full article here