Allelic variation of the serotonin transporter gene polymorphic region in apes

To assess the change of serotonin transporter (5-HTT) gene-linked polymorph ic region that has occurred during the process of hominization, we examined the allelic variation of 5-HTT gene-linked polymorphic region (5-HTTLPR) i n anthropoid apes such as chimpanzees, gorillas, orang-utans, and gibbons, and determined the DNA sequences of the alleles in each species. All chimpa nzees examined shared only the 17.5 repeat allele, while polymorphism was o bserved in the other apes and the 16 and 20 repeat alleles were most freque nt in gorillas and orang-utans, respectively. 5-HTTLPR was highly polymorph ic in gibbons and the 17 and 23 repeat alleles were most common among 5 all eles. Alleles with extra-long repeated (22 and 23) sequences were found in orang-utans and gibbons, and the alleles of these Asian apes were similar t o the rhesus monkey allele.