Objective In order to increase significantly the discriminatory potential of Y-STR systems available to the forensic community , We have developed and validated a four-color fluorescence multiplex PCR system consisting of 7 male-specific and polymorphic Y-STRs. Methods We designed three sets of constant primers chimerited into three groups of 7 Y-STR's specific primers and utilized fluorescence- labeled these three sets of constant primers to amplified simultaneously 7 Y-STRs in a reaction tube. Allele and haplotype frequencies at these Y-STRs were screened by ABI PRISM310 Genetic Analyzer and analyzed by Genotyper software. Results Following optimization of the polymerase chain reaction , DYS434, Y-GATA-A10,DYS531, DYS557 , DYS456 , DYS444 and DYS448 in a sample of 120 unrelated males , showed4, 5, 5, 8, 8, 6,7 alleles respectively. A total of 101 different haplotypes was identified,of which 89 (88. 11% ) were found in single individuals. The overall haplotypes diversity reached 0.9958. To the one case of mixture stains, our multiplex system drawn conforming conclusion comparing to the result of Y-STR genotypes in suspect's blood sample. Conclusion Our results show that the multiplex system of 7 Y-STR will be very powerful for establishing Y-STR database, the paternity testing and mixture stains identifying.

Objective To investigate the genetic polymorphisms of 27 Y-chromosomal short tandem repeats (Y-STR) loci included in Yfiler(R) Plus kit in Han population of Chaoshan area,and explore the population genetic relationships and evaluate its application value on forensic medicine.Methods By detecting 795 unrelated Chaoshan Han males with Yfiler(R) Plus kit,haplotype frequencies and population genetics parameters of the 27 Y-STR loci were statistically analyzed and compared with available data of other populations from different races and regions for analyzing the genetic distance and clustering relation of Chaoshan Han population.Results Seven hundred and eighty-seven different haplotypes were observed in 795 unrelated male individuals,of which 779 haplotypes were unique,and 8 haplotypes occurred twice.The haplotype diversity (HD) was 0.999975 with discriminative capacity (DC) of 98.99％.The gene diversity (GD) at the 27 Y-STR loci ranged from 0.3637(DYS391) to 0.9559(DYS385a/b).Comparing with Asian reference populations,the genetic distance (Rst) between Chaoshan Han and Guangdong Han was the smallest (0.0036),while it was relatively larger between Chaoshan Han and Gansu Tibetan population (0.0935).The multi-dimensional scaling (MDS) plot based on Rst values was similar to the results of clustering analysis.Conclusion Multiplex detection of the 27 Y-STR loci reveals a highly polymorphic genetic distribution in Chaoshan Han population,which demonstrates the important significance of Yfiler(R) Plus kit for establishing a Y-STR database,studying population genetics,and for good practice in forensic medicine.

Objective To establish the rapid PCR am plification program and system and to verify the technical indexes. Methods PCR m ultiplex and capillary electrophoresis detection of 24 autosom al STR loci and one Y-STR loci using the 6-color fluorescence m arking technology, as w ell as Amelogenin and Y-InDel. Meanw hile, sensitivity, specificity, identity, stability, m ixing and a batch of sam ple tests w ere investigated, and the genotype of various routine sam ples and degraded, exfoliated cell sam ples w ere observed. Results The sensitivity of the system w as 0.062 5 ng. In addition, the genotype could be detected accu-rately only around 65 m in via rapid am plification. The species-specificity w as high and the genotyping of all kinds of dry blood specim ens of filter paper and m ixed, degraded, exfoliated cell sam ples w ere accu-rate. Conclusion The rapid am plification system can significantly im prove the detection rate, and obtain accurate and stable genotyping results, w hich m ay be im portant im plications for the establishm ent of STR database and study on population genetics and forensic identification.

OBJECTIVETo analyze the genetic data of 30 insertion and deletion polymorphisms (InDel) loci included in an InvestigatorR DIPplex diagnostic kit, and to evaluate the forensic application in ethnic Tibetan population from China.

METHODSBy detecting 226 unrelated individuals with the Investigator(R) DIPplex kit, allelic frequencies and population genetics parameters of the 30 InDels were statistically analyzed and compared with available data derived from other populations from various regions.

RESULTSAfter the Bonferroni correction at a 95% significance level (P=0.0017), no significant departures from the Hardy-Weinberg equilibrium were observed except for the HLD114 locus. Linkage disequilibrium test showed no significant allelic association between all 30 loci after the Bonferroni's correction. The average heterozygosity (Ho) of all loci was 0.4125, the mean discrimination power (DP) was 0.5618, the mean polymorphism information content (PIC) was 0.3280, and the combined discrimination power (TDP) was 0.999999999990. The combined power of exclusion of all loci was 0.987 849 91 in trio cases and 0.94977125 in duo cases. Genetic distance between Tibetan and Han from Beijing was minimum (0.0068) in the 5 populations, while genetic distance between Tibetan and Uygur was maximal (0.0215).

CONCLUSIONMultiplex detection has revealed that these 30 InDel loci have a moderate distribution of genetic polymorphism among ethnic Tibetan group residing in Tibet, China.

Adult ; Asian Continental Ancestry Group ; ethnology ; genetics ; Female ; Gene Frequency ; Humans ; INDEL Mutation ; Linkage Disequilibrium ; Male ; Middle Aged ; Polymorphism, Genetic ; Tibet ; ethnology ; Young Adult

OBJECTIVETo analyze linkage disequilibrium of 12 short tandem repeat loci on chromosome X (X-STR) among an ethnic Han population from Guilin, Guangxi, and to study the genetic linkage and haplotype distributions of such loci in 2 linkage groups.

METHODS12 X-STR loci including DXS8378, DXS10159, DXS10162, DXS10164, DXS981, DXS6789, DXS7424, DXS101, DXS7133, GATA165B12, GATA31E08 and DXS7423 were genotyped using an AGCU X12 STR PCR Amplification kit. A total of 119 pedigrees were analyzed for linkage and linkage disequilibrium.

RESULTSTwo mutations were found at DXS7424, and 1 mutation was found at DXS10164. A total of 93 haplotypes of DXS10159-DXS10162-DXS10164 were constructed for 261 unrelated males and females, in addition with 167 haplotypes of DXS6789-DXS7424-DXS101-DXS7133. The values of recombination fraction between DXS10159 and DXS10162, DXS10162 and DXS10164, DXS6789 and DXS7424, and DXS7424 and DXS101 were 0.0269, 0.0236, 0.0505 and 0.0438, respectively.

CONCLUSIONLinkage disequilibrium of X-STR does not only depend on physical and genetic distances. There was incomplete linkage relationship between loci on DXS10159-DXS1016-DXS10164 and DXS6789-DXS7424-DXS101 linkage groups.

Adolescent ; Adult ; Asian Continental Ancestry Group ; ethnology ; genetics ; Child ; Child, Preschool ; China ; ethnology ; Chromosomes, Human, X ; genetics ; Female ; Haplotypes ; Humans ; Linkage Disequilibrium ; Male ; Microsatellite Repeats ; Middle Aged ; Pedigree ; Young Adult