Abstract
(Object) A four-base repeat of vole arginine vasopressin receptor 1a gene (AVPR1A) promoter region is reported to be associated with expression in the brain and the social attachment between mates. The corresponding region of human AVPR1A contains three repetitive sites, RS1, RS2 and RS3 named by distance from transcription start sites. The RS2 is a susceptible locus of human autism. To identify the genetic background of the social behaviors in primates, we surveyed these regions. (Materials and Methods) In this study, we surveyed the regions in humans (20 Japanese), great apes (68 chimpanzees, 16 gorillas, and 18 orangutans), and lesser apes (8 white-handed gibbons, 7 agile gibbons, and 7 siamangs). In addition, we tested those regions in eleven Old World monkeys of five species, and each one of night monkey, lemur, and tree shrew as outgroup. (Results and Discussion) All apes lineage with Old World monkeys could be amplified for the RS1 region, and length polymorphisms were detected. The observed allele lengths of lesser apes were shorter than those of great apes and Old World monkeys. Since the RS1 is likely corresponding region to vole's social attachment locus, there might be any influence on primate social system. The RS2 region was reportedly deleted in chimpanzees, but we found this region was not deleted in all other apes. The same deletion with chimpanzees was observed in all other primates. The RS2 region will be a good subject for the study about mutation mechanism. The RS3 could not be efficiently amplified except humans and African great apes (chimpanzees and gorillas). Wide range allele distribution was detected in these species.
