Novel strategy of multiple-locus variable number tandem repeats analysis for genetic fingerprinting of human.

Background: The variable number of tandem repeat (VNTR) analyses are methods based on the detection of repeated sequences within the human genome. In order to perform DNA typing at the personal laboratory, it is necessary to improve the VNTR analysis.

Objective: The VNTR markers were difficult to popularize because PCR amplification was difficult due to its GC-rich and long nucleotide sequence. The aim of this study was to select the multiple VNTR markers that could only be identified by PCR amplification and electrophoresis.

Methods: We genotyped each of the 15 VNTR markers using genomic DNA from 260 unrelated individuals by PCR amplification. Differences in the fragment length of PCR products are visualized by agarose gel electrophoresis. To confirm their usefulness as a DNA fingerprint these 15 markers were simultaneously analyzed with the DNA of 213 individuals and verified the statistical significance. In addition, to investigate the usefulness of each of the 15 VNTR markers as paternity markers, Mendelian segregation by meiotic division within a family consisting of two or three generations was confirmed.

Results: Fifteen VNTR loci selected in this study could be easily amplified by PCR and analyzed by electrophoresis, and were newly named DTM1 ~ 15. The number of total alleles in each VNTR showed from 4 to 16, and 100 to 1600 bp in length, and their heterozygosity ranged from 0.2341 to 0.7915. In simultaneous analysis of 15 markers from 213 DNAs, the probability of chance appearing the same genotype in different individuals was less than 4.09E-12, indicating its usefulness as a DNA fingerprint. These loci were transmitted through meiosis by Mendelian inheritance in families.

Conclusion: Fifteen VNTR markers have been found to be useful as DNA fingerprints for personal identification and kinship analysis that can be used at the personal laboratory level.