Human chromosome Y-specific short tandein repeat (Y-specific STR) markers have useful properties for forensic appplications However, there is a need to develop more Y-specific STR markers, because the discriminating power of each STR locus is liinited In the present study, we describe our results on six new Y-specific STR markers that were initially located using sequence database infomlation by Ayub et al and were named DYS434, DYS435, DYS436, DYS437. DYS438 and DYS439. Our stndies focused on the analysis of the DNA sequence for each allele at all six Y-specific STR loci in order to mlderstand their structures in the human genome and to construct human allelic ladders. which are necessary for forensic DNA typing in addition. the haplotype distribution for all six analyzed loci was studied in a Chinese Han population sample The results indicate that DYS434. DYS435, DYS436. DYS437, DYS438 and DYS439 are useful Y-specific STR markers for forensic sciences.

The amplifiable VNTR polymorphic system COL2A1 has been investigated in Chinese and German population samples. In order to accurately identify COL2A1 alleles. a number of hu-man allele ladders were prepared. A total of 14 different alleles in 23 genotypes was observed in the Chinese population. while in the German population there were 11 alleles in 24 geno-types. Four new alleles were observed. AIl of them werc found in the Chinese and one was also observed in the German pop-ulation. There was no statisticaI difference in the allele distri-bution between two Gcrman populations from Miinster and Koln, while the allele frequency distribution in the Chinese population differed significantly from the German.

In order to evaluate the forensic applicability of the STR locus D20S161 and construct a preliminary database, the genotype distributions and allele frequencies in five populations from three main ethnic groups were investigated, including Germans, Slovakians, African Americans, Japanese and Chinese. A total of 512 samples from unrelated individuals and 85 confirmed father/mother/ child triplets were analyzed by PCR and allele determination was carried out by comparison with a sequenced human allelic ladder. The results showed that D20S161 typing was both precise and reliable. A total of 7 alleles was found in these populations and no evidence of deviation from Hardy-Weinberg equilibrium was observed. Pairwise comparisons between populations showed that there were significant differences in the distributions of the allele frequencies among the three main ethnic groups. No mutation events were observed from the confirmed father/mother/child triplets. With a maximum likelihood method, the mutation rate was indirectly estimated as 2.5 × 10–5. These results suggest that D20S161 is a useful marker for forensic casework and paternity analysis.

The purpose of our work was to establish a method for analysis of Y-SNP based on the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The results of our study implied that the analysis of Y-SNP was proved to be suitable for forensic application and provided new genetic markers for the forensic purpose. D 2005 Published by Elsevier B.V.