The enlargement of cetacean brain size represents an enigmatic event in mammalian evolution,yet its genetic basis remains poorly explored.Primary microcephaly (MCPH) genes (MCPH1-7,i.e.MCPH1,WDR62,CDK5RAP2,CEP152,ASPM,CENPJ,and STIL) are thought to play key roles in size regulation during brain development due to the fact that mutations in these genes can causes a severely developmental defect of cerebral cortex.