Genetic analysis of 39 Y-STR loci in a Han population from Henan province, central China.

A total of 39 Y-chromosomal short tandem repeat (Y-STR) loci included in the advanced commercial six-dye multiplex system (AGCU Database Y30 kit) and a custom-designed four-dye multiplex system were investigated in 259 unrelated healthy Chinese males residing in Henan Province, central China. The haplotype diversity (HD) values were 0.99997 and 1.0000 for the six and four fluorescent-multiplex amplification systems, respectively. The discrimination capacity (DC) values were 0.9961 and 1.0000, respectively. When the 39 Y-STR loci were considered, 259 unique haplotypes were obtained in Henan Han individuals with both the haplotype diversity and discrimination capacity being 1.000. The gene diversity (GD) of 39 Y-STR loci in the studied group ranged from 0.3956 (DYS588) to 0.9990 (DYF403S1). Population comparisons between the Henan Han and 24 reference groups were performed. Both multidimensional scaling plots and phylogenetic analysis demonstrated that significant genetic differences existed between Henan Han and reference ethnic minorities of China, particularly the Tibetan, Uighur, and Mongolian populations. Moreover, the results indicated that 39 Y-STRs included in the two fluorescent-multiplex amplification systems are highly polymorphic and informative in the studied populations and can be employed as complementary tools for forensic application and human genetics research.

Tri-allelic patterns of STRs and partially homologous non-sister chromatid crossover observed in a parentage test.

A maternity testing case is reported, in which the child showed tri-allelic patterns in two short tandem repeat (STR) loci. The genotypes of Penta D of the mother and the child were 9,13 and 9,10,13, respectively. Those of D21S11 were 32.2,35 and 29,35, respectively, but intensity ratio of alleles 29 and 35 of the child was 1:2. These results suggested the copy number variations (CNVs) or trisomy of chromosome 21. By further examination using STR-based chromosome aneuploidy detection kit, three alleles were detected in D21S1411, LFG21 and Penta D, and 2 alleles with intensity ratio of 1:2 were observed in D21S2502, D21S1435, D21S11 and D21S1246. Karyotype and whole-genome SNP array analyses showed that the child had a free trisomy 21. In addition, partially homologous non-sister chromatid crossover occurred at the region 19181770-39499178 on the long arm of chromosome 21.