doi:10.1098/rsbl.2006.0586
Biol. Lett.(2007)3, 157–160 doi:10.1098/rsbl.2006.0586 Published online23 January 2007 Evolutionary biology No evidence that polymorphisms of brain regulator genes MicrocephalinandASPM are associated with general mental ability, head circumference or altruism J. Philippe Rushton*, Philip A. Vernon and Trudy Ann Bons The University of Western Ontario, Ontario, Canada N6A 3C2 *Author for correspondence([email protected]). We test the hypothesis that polymorphisms of the brain regulator genesMCPH1andASPM contribute to variations in human brain size and its correlates. We measured general mental ability, head circumference and social intelligence in 644 Canadian adults (496 Caucasians, 36 Orientals, 84 Mixed Race/Other and 28 Blacks; 257 men and 387 women). The gene polymorphisms were assessed from buccal DNA; mental ability by Wonderlic Personnel Test and Multidimensional Aptitude Battery; head circumference by stretchless tape; and social intelligence by prosocial attitude ques- tionnaires. Although all measures were construct valid and the allele frequencies showed expected population differences, no relationship was found between the genes and any of the criteria. Among Caucasian 18–25 year olds, for example, the two mental ability tests correlated with each other (rZ0.78,NZ476,p!0.001), with head circumfer- ence (rZ0.17,NZ182,p!0.05) and with prosocial attitudes (rZ0.23,NZ182,p!0.001). Keywords:altruism; brain size; genes; general intelligence; social intelligence 1. INTRODUCTION Two newly discovered genes,Microcephalin(MCPH1) on chromosome 8p23 and abnormal spindle-like microcephaly associated (ASPM) on chromosome 1q31, attracted much attention when reported to be (i) associated with autosomal recessive primary microcephaly, (ii) positively accelerated in molecular evolutionary rate through the simian line leading to Homo sapiens, and (iii) under recent positive selection in modern humans (Evanset al. 2005;Mekel-Bobrov et al. 2005). TheMCPH1allele favoured by selecti…