Forensic Application Evaluation of a Novel Canine STR System in Pembroke Welsh Corgi and Shiba Inu Groups

Aim. To evaluate the forensic application values of 19 autosomal short tandem repeat (STR) loci in canines. Methods. The 19 STR loci in two canine groups (Pembroke Welsh Corgis, n = 200 ; Shiba Inus, n = 175 ) were analysed by the capillary electrophoresis platform. The allele frequencies and forensic parameters were calculated, and the genetic relationships between these two canine groups and a previously reported Labrador group were analysed. Results. These two canine groups conformed to the Hardy-Weinberg equilibrium at all STRs except for locus VGL3438 in the Pembroke Welsh Corgi group, and there was no linkage disequilibrium among pairwise loci at the 19 STRs. All STRs were polymorphic in the Pembroke Welsh Corgi and Shiba Inu groups, of which the locus C38 had the highest polymorphism. And it was found that the genetic relationship between the Pembroke Welsh Corgi and Labrador groups were closer in the three canine groups (Pembroke Welsh Corgi, Shiba Inu and Labrador). Conclusion. The 19 STR loci had high genetic polymorphisms and forensic application values in Pembroke Welsh Corgi and Shiba Inu groups.

Identification and Characterization of Nine Novel X-Chromosomal Short Tandem Repeats on Xp21.1, Xq21.31, and Xq23 Regions

The application of X-chromosomal short tandem repeats (X-STRs) has been recognized as a powerful tool in complex kinship testing. To support further development of X-STR analysis in forensic use, we identified nine novel X-STRs, which could be clustered into three linkage groups on Xp21.1, Xq21.31, and Xq23. A multiplex PCR system was built based on the electrophoresis. A total of 198 unrelated Shanghai Han samples along with 168 samples from 43 families was collected to investigate the genetic polymorphism and forensic parameters of the nine loci. Allele numbers ranged from 5 to 12, and amplicon sizes ranged from 146 to 477 bp. The multiplex showed high values for the combined power of discrimination (0.99997977 in males and 0.99999999 in females) and combined mean exclusion chances (0.99997918 and 0.99997821 in trios, 0.99984939 in duos, and 0.99984200 in deficiency cases). The linkage between all pairs of loci was estimated via Kosambi mapping function and linkage disequilibrium test, and further investigated through the family study. The data from 43 families strongly demonstrated an independent transmission between LGs and a tight linkage among loci within the same LG. All these results support that the newly described X-STRs and the multiplex system are highly promising for further forensic use.

Genetic analysis of father-daughter incest using multifaceted STR markers and study of inheritance pattern of alleles

Background: Two cases involving father-daughter incest, a rare report in the Indian population, have been analyzed in the current study. STR markers on both autosomal and sex chromosomes were employed to expound the cases. Objective: To confirm the identity of the fetus as a product of father-daughter incest and to study the inheritance pattern of alleles in such cases. Results: In both cases, the aborted fetus was found to be the product of an incestuous father-daughter relationship. The probability of paternity as well as maternity was found to be >99.9999% in both cases. Analysis of other paternity and forensic parameters also substantiated the inclusion of the alleged individuals. Father-daughter incest had a tremendous effect on the genome as evidenced from the dramatical decrease in unrelated alleles between father/child [16.66% (Case 1), 20% (Case 2)] and mother/child [26.66% (Case 1), 21.66% (Case 2)]. Genetic evidence also suggested an increased biallelic match i.e., 26.66% (Case 1) and 33.33% (Case 2) between mother and fetus which are at par/ above the normal siblings’ values i.e., 26.66%. Conclusion: A significant increase in the percentage of homozygous alleles (53.33% in both cases) was observed in the product of father-daughter incest. Both daughters share the same X chromosome from the father, which also suggested the case to be of father-daughter incest. Similarly, the same Y-STR profile between the male fetus and alleged father confirmed the correct pattern of inherit1ance of the Y chromosome in this case.

Insights From Y-STRs: Forensic Characteristics, Genetic Affinities, and Linguistic Classifications of Guangdong Hakka and She Groups

Guangdong province is situated in the south of China with a population size of 113.46 million. Hakka is officially recognized as a branch of Han Chinese, and She is the official minority group in mainland China. There are approximately 25 million Hakka people who mainly live in the East and North regions of China, while there are only 0.7 million She people. The genetic characterization and forensic parameters of these two groups are poorly defined (She) or still need to be explored (Hakka). In this study, we have genotyped 475 unrelated Guangdong males (260 Hakka and 215 She) with Promega PowerPlex® Y23 System. A total of 176 and 155 different alleles were observed across all 23 Y-STRs for Guangdong Hakka (with a range of allele frequencies from 0.0038 to 0.7423) and Guangdong She (0.0047–0.8605), respectively. The gene diversity ranged from 0.4877 to 0.9671 (Guangdong Hakka) and 0.3277–0.9526 (Guangdong She), while the haplotype diversities were 0.9994 and 0.9939 for Guangdong Hakka and Guangdong She, with discrimination capacity values of 0.8885 and 0.5674, respectively. With reference to geographical and linguistic scales, the phylogenetic analyses showed us that Guangdong Hakka has a close relationship with Southern Han, and the genetic pool of Guangdong Hakka was influenced by surrounding Han populations. The predominant haplogroups of the Guangdong She group were O2-M122 and O2a2a1a2-M7, while Guangdong She clustered with other Tibeto-Burman language-speaking populations (Guizhou Tujia and Hunan Tujia), which shows us that the Guangdong She group is one of the branches of Tibeto-Burman populations and the Huonie dialect of She languages may be a branch of Tibeto-Burman language families.

Development and validation of a multiplex 19 X-chromosomal short tandem repeats typing system for forensic purposes

X-chromosome short tandem repeat (X-STR) markers are a powerful complementary system used for paternity and forensic casework. This study presents the development and validation of a new highly efficient multiplex-fluorescent-labeled 19 X-STR typing system, including DXS10079, DXS101, DXS10135, DXS10162, DXS6795, DXS6800, DXS6803, DXS6807, DXS6809, DXS6810, DXS7133, DXS7423, DXS981, DXS9902, DXS9907, GATA165B12, GATA172D05, GATA31E08 and HPRTB along with sex-typing locus, amelogenin. The system was validated according to guidelines issued by the Scientific Working Group on DNA Analysis Methods. Allele frequency and forensic parameters were investigated from 1085 (494 males and 591 females) unrelated Beijing Han individuals, the combined power of discrimination by the 19 X-STR loci in females and males, as well as the combined mean exclusion chance in trios and duos, were 0.999999999999999995, 0.99999999995, 0.9999999995, and 0.9999996, respectively. The results demonstrate that this multiplex system is robust and reliable, and considered to be a powerful tool for forensic application.