Forensic characterisation and polymorphism analysis of 16 X-chromosomal STRs in the Jining Han population in Eastern China.

BACKGROUND: X-chromosomal short tandem repeats (X-STRs) are a useful supplementary approach to analysing autosomal markers in forensics and kinship studies; such markers are not well-characterised in many populations. AIM: To investigate population genetic polymorphism and forensic characterisation of 16 X-STRs in the Jining Han population, and analyse genetic relationships with other Chinese populations. SUBJECTS AND METHODS: Allele frequencies for 16 X-STR loci were obtained from a sample set of 527 unrelated individuals from the Jining Han population. Population genetic analyses of Jining Han and another 10 reference populations were conducted using phylogenetic tree, principal component analysis and multidimensional scaling. RESULTS: We detected 149 alleles, with frequencies ranging from 0.0013 to 0.8242. The combined powers of discrimination in males and females were 0.999999997194774 and 0.999999999999995, respectively. The combined mean exclusion change (MEC)Krüger, MECKishida, MECDesmarais, and MECDesmarais Duos values were 0.999974632649096, 0.999999976997582, 0.999999977013201, and 0.999993755768423, respectively. We detected relatively high genetic homogeneity in populations with similar ethnic or geographic origins, and a close relationship between the Jining Han and Beijing Han populations. CONCLUSIONS: The present findings indicate that the 16 X-STR loci examined are highly polymorphic in the Han population of Jining, providing useful information for forensic science and population genetics studies.

Genetic polymorphism and forensic efficiency of 21 autosomal STR loci from Shandong Han population in Northern China.

BACKGROUND: Highly polymorphic autosomal STR loci are useful for understanding population structure better and for forensic application, however the non-CODIS STR loci in the Han population of Shandong, located in Northern China, are not well-characterised. AIM: To investigate population genetic polymorphism and forensic efficiency of 21 autosomal STR loci from the Shandong Han population in Northern China and reveal the genetic relationships with other populations both at home and abroad. SUBJECTS AND METHODS: In this study, population genetic data of 21 autosomal STR loci included in the Goldeneye DNA ID 22NC Kit that includes four CODIS loci and 17 non-CODIS loci were determined for 523 unrelated Han individuals in Shandong. RESULTS: Significant deviations from Hardy-Weinberg equilibrium were not observed. A total of 233 alleles were detected with allele frequencies ranging from 0.0010 to 0.3728. The combined power of discrimination was 0.99999999999999999999999990011134, and the combined power of exclusion was 0.99999999788131. Furthermore, in an analysis of population differentiation Nei's standard genetic distance and multidimensional scaling analysis, which were conducted based on the overlapping 15 STR loci, revealed that the Shandong Han population was most closely related to populations in close geographic proximity. CONCLUSIONS: This study demonstrated that the 21 autosomal STR loci included in the GoldeneyeTM DNA ID 22NC system are highly polymorphic and suitable for forensic identification and paternity testing in the Shandong Han population. Additionally, the present results enrich the population genetic database.

Verification of a loss of heterozygosity at the D8S1179 locus in a paternity case by the MiSeq FGx system.

Capillary electrophoresis is widely used to study short tandem repeats (STRs) in forensic genetics. However, next-generation sequencing platforms have become a new strategy for forensic DNA typing. In this study, we report a false four-step STR mutation between an alleged father (AF) and child in a paternity case. A total of 23 autosomal STR loci were evaluated using the Huaxia™ Platinum and Goldeneye™ 20A kits, revealing a single mismatch in D8S1179 between the AF (10/10) and the male child (14/14). Additional Y-STR typing of the AF and child was performed, and the results were consistent with those based on 27 Y-STR loci. To further confirm the experimental results, we sequenced the individuals using the MiSeq FGx system and detected 10/15 unbalanced alleles in the D8S1179 locus of the AF and 14/15 unbalanced alleles in the D8S1179 locus of the child. Sanger sequencing revealed that both the AF and child had the C→G point mutation in the primer binding region of D8S1179 resulting in allelic dropout. Therefore, the verification of STR typing by different sequencing systems is helpful for the interpretation of results in cases of multistep STR mutations.