2002 Volume 13 Issue 2 Pages 57-62
The D4 dopamine receptor gene (DRD4) polymorphic region, which is possibly related to the personality trait known as Novelty Seeking in humans, was examined in equids. Partial nucleotide sequences in exon 3 of DRD4 gene were compared among several species in genus Equus. Inter-and intra-species differences were observed, as well as between two domestic horse breeds, Thoroughbred and Kiso pony (Japanese native pony). In equids, these variations were consisted of as many as 9 fold repeats of 18 bp variable number of tandem repeat (VNTR) type polymorphisms and single nucleotide polymorphisms (SNPs).