Trinucleotide Repeat Polymorphisms of Spinocerebellar Ataxia Type 1 Gene (SCA1) in Asian Populations

摘要

The Spinocerebellar ataxia type 1 (SCA1) locus is highly polymorphic and the sequence of this gene is variable between individuals. In this report we examined the PCR-based SCA1 region polymorphisms in four Northeast Asian populations, two Northeast Asian ethnic groups, a Southeast Asian ethnic group (Negrito) and Caucasians as controls. In total, 818 individuals were investigated. They were found to exhibit highly polymorphic allele distributions. The allele distributions were significantly different among populations (one-way ANOVA: F = 11.700, p = 0.000; Kruskal-Wallis test: x~2 = 114.494, DF = 7, p < 0.001) and among three groups (Northeast Asians, Negrito, and Caucasians) (one-way ANOVA: F = 30.267, p <0.001; Kruskal-Wallis test: x~2 = 92.206,DF = 2, p < 0.001). Post hoc test showed that the difference between Northeast Asians and Caucasians was especially significant (Scheffe: p < 0.001; Bonferroni: p < 0.001). Negritos showed a unique allele distribution, which was more distantly separatedfrom Caucasians (Scheffe: p = 0.030; Bonferroni: p = 0.025) than from Northeast Asians (Scheffe: p = 0.307; Bonferroni: p = 0.374). Furthermore the pairwise Fst distances and Unrooted Neighbor Joining (NJ) analysis represented that Negritos and Caucasians were genetically distant from the other Northeast Asians. The result of NJ analysis also suggested that Koreans are more closely related with Japanese and Chinese than Mongolians among East Asian populations.