Analysis of hypervariable minisatellites and their flanking sequences towards application to forensics polymorphic markers

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Some minisatellite loci show very high levels of allele length variability. Most minisatellite loci consist of heterogeneous arrays of two or more subtly different repeat unit types (minisatellite variant repeats). Interspersion patterns can be determined by MVR mapping. We analysed the properties of a hypervariable minisatellite CEB1 (D2S90) in the Japanese population. The length heterozygosity is observed at 85.0% and the average length of the alleles is 69 repeats. A new single nucleotide polymorphism (SNP) was found in the flanking the minisatellite. Internal MVR structure was different between alleles and new base substitutions / deletions were found within repeats, which indicates CEB1 is also one of the most hypervariable minisatellite loci in Japanese. Minisatellite MS32 (D1S8) is also one of the minisatellites that shows vast diversity by MVR-PCR. Almost all alleles in several ethnic populations surveyed were found to be different. However, distinct alleles can show significan … More t similarities in repeat organization. However, up until now the existing Asian database has consisted almost entirely of Japanese alleles. In order to explore the similarities between Japanese and other Asian alleles, we have started MS32 allele mapping of DNA samples from Thais. By using allele-specific primers in MVR-PCR of individuals heterozygous for a SNP, 120 alleles can be mapped by the allele-specific MVR-PCR of the SNP. In 106 mapped Thai alleles, there are only 2 pairs of alleles are indistinguishable, and the remaining 102 alleles are unique. Under the infinite allele model and assuming selective neutrality, these data give an estimated theta. value of 2710 for the Thai. This estimate of diversity also suggests a heterozygosity of 99.96%. Allele codes were compared with each other by heuristic dot matrix analysis. MS32 Allele code database consisting 1072 alleles of various ethnic populatioins was also used. Within Thai aleles, 41 showed significant inter-allelic similarities, corresponding to 39% of all mapped alleles. Compared with world alleles, 57 were confirmed their similarities are authentic corresponding to 54% of all mapped alleles. Among the related Thai alleles, 64% of alleles show significant similarities to Japanese alleles and 26% to Caucasian. No Tahi alleles are related to African alleles. Therefore, Thai alleles are largely Asian population-specific, although the tendency does not seem to be as high as in Japanese. MVR allele analysis at MS32 can act as a tool not only for individual identification but also for ethnic background providing useful lineage markers for exploring recent events in human population history. Less