Distribution of the 3 ' VNTR polymorphism in the human dopamine transporter gene in world populations

A polymorphism with a variable number of tandem repeals (VNTR) found in the 3' untranslated region of the human dopamine transporter gene (DATI) was s cored in unrelated individuals drawn from 10 geographically widely disperse d populations in order to assess this marker's usefulness in human populati on genetics. The populations that were analyzed in this study included 4 in digenous groups of Siberia, natives of North and South America, as well as Caucasian and Oceanic groups, most of which represented small-scale societi es, A total of 5 DATI alleles were seen overall, but only in one Siberian p opulation, the Altai-Kizhi, were all 5 present, and in the Native Americans of Colombia the locus was monomorphic. The most common allele, DATI*10, ra nged in frequency from 52% in Greeks to 100% in South Americans. The high f requency of the DATI*10 allele (similar to 90%) among Mongoloid groups of n orth and east Asia distinguishes them from most Caucasian groups. The prese nce of the rare DAT1*7 allele in relatively high frequency (similar to 5%) among all Siberian groups suggests a close affinity with north Asian groups , especially Mongolians. The presence of the even rarer DATI *13 allele in one Siberian population, the Altai-Kizhi, reflects this group's long histor ical contact with Mongolians. The results demonstrated that the DATI VNTR p olymorphism is useful in investigating population relationships, and that r are alleles at this locus may be particularly valuable in understanding the extent of genetic affinity between neighboring groups and in situations wh ere admixture is suspected. However, because of both the association and li nkage of this VNTR locus with attention-deficit hyperactivity disorder (ADH D) in children, and its highly restricted polymorphism (usually 3 alleles) in most human groups, the possibility, of selection constraints on the DAT1 gene cannot be ignored.