Brain gene expression signature on primate genomic sequence evolution.

Considering the overwhelming changes that occurred during primate evolution in brain structure and function, one might expect corresponding changes at the molecular level. Surprisingly, a relatively constrained gene expression pattern is observed in brain compared with other tissues among primates, an observation that calls for reassessment of RNA expression influence on primate genome evolution. We built phylogenetic trees based on genomic sequences of functional genomic regions and tissue-specific RNA expression in eight tissue types for six primate species. Comparisons of the phylogenetic trees from brain tissues revealed that DNA- and RNA-based trees were significantly similar. The similarity was specific for promoter regions and cerebellum and frontal cortex expression, suggesting a major impact of gene regulation in the brain on genome shaping along the primate branch.