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Background: Insertions and deletions (Indels) have been used in routine forensic studies, archaeology, and population genetics. They have certain advantages, such as absence of stutter, small amplicon lengths, and low mutation rates. The genetic variations and forensic features of Indels in the Wuzhong Hui population are, as yet, unclear. Aim: To investigate the genetic polymorphisms of 30 Indels in Wuzhong Hui people and explore their genetic relationship with 48 reference populations from all over the world. Subjects and methods: We genotyped 30 Indels included in the Investigator DIPplex Kit in 156 Wuzhong Hui individuals. The genetic polymorphisms and population genetic relationships were analysed and explored via pairwise Fst, principal component analysis, multidimensional scaling plots, phylogenetic tree, and structure. Results: The combined power of discrimination (CPD) and the combined probability of exclusion (CPE) were 0.9999999999899 and 0.9880, respectively. Population genetic diversity and affinity were associated with geographic origin and linguistic affiliation. Conclusions: The 30 Indels can be utilised as an important tool in forensic personal identification and as a supplementary method in paternity testing in Wuzhong Hui. The Wuzhong Hui people have a close genetic relationship with populations of geographical proximity and Sinitic-speaking populations, while they are different from other continental populations and Turkic-speaking populations. [ABSTRACT FROM AUTHOR]

Background: The value of using X-chromosomal short tandem repeats (X-STRs) as genetic markers in human genetics has been widely recognised. However, the 16 X-STRs in the Goldeneye® DNA ID System 17X kit have not been thoroughly applied. Aim: To investigate the genetic polymorphisms of 16 X-STRs in three main ethnic minorities (Tibetan, Mongolian and Kazakh) in China and to reveal the phylogenetic relationships of different populations. Subjects and methods: A total of 245 Tibetan, 168 Mongolian and 105 Kazakh individuals were genotyped using this 17X kit. The allelic frequencies and other parameters were calculated. An additional eight Chinese populations and nine global populations were included in genetic comparisons based on 16 or 8 overlapped X-STRs. Results: A total of 147 alleles were observed from 16 X-STRs with allelic frequencies ranging from 0.0024 to 0.7952 in the three studied groups. Based on 16 X-STRs, Tibetans, Kazakhs and Mongolians showed more similarity to each other and were genetically distinct from the Shanghai Han group; based on 8 X-STRs, only the genetic relationships between different nations could be clarified. Conclusions: Our study presents an extensive report on a novel X-STR assay in three Chinese ethnic groups and a comprehensive genetic comparison between different populations based on these X-STRs. [ABSTRACT FROM AUTHOR]

Genetic characterization of ethnically and geographically diverse populations via short tandem repeats (STRs) is relevant to various fundamental and applied areas of forensic genetics, population studies, and even molecular anthropology. In the present study, genetic polymorphisms of 15 autosomal STR loci were firstly obtained from 918 individuals (495 Nakhis and 423 Yis) residing in the foothills of the Himalayas. The cumulative powers of discrimination and probabilities of exclusion in the two studied ethnic groups were both larger than 0.999999999999999982 and 0.9999961, respectively. Genetic similarities and differences among 61 populations were subsequently investigated by pairwise Cavalli-Sforza genetic distance, multidimensional scaling plots, principal component analysis, and phylogenetic relationship reconstruction. Both Nakhi and Yi had the genetically close relationships with Yunnan Bai and distinct relationships with Xinjiang Turkic-speaking populations (Uyghur and Kazakh) and Vietnamese. [ABSTRACT FROM AUTHOR]

Forensic identification of sudden unexplained death (SUD) has always been a ticklish issue because it used to be defined as sudden death without a conclusive diagnosis after autopsy. However, benefiting from the developments in genome research, a growing body of evidence points to the importance of ion channelopathies associated genetic variants in the pathogenesis of SUD. Genetic diagnosis of the deceased is also a new trend in epidemiological studies, for it enables the undertaking for preventive approach in individuals with high risks. In this review, we briefly discuss the molecular structure of ion channels and the role of genetic variants in regulating their functions as well as the diverse mechanisms underlying the ion channelopathies at gene level. [ABSTRACT FROM AUTHOR]

Abstract: X-ray repair cross-complementing 5 (XRCC5) is a gene involved in repair of DNA double-strand breaks. Abnormal expression of the XRCC5 protein is associated with genomic instability and an increased incidence of cancers. In our study, a polymorphism with a variable number of tandem repeats (21-bp repeat elements at position −201 to −160 relative to the initiation of transcription) in the promoter of XRCC5 was identified. As determined with gel-shift and super-shift assays, the binding affinity of the transcription factor Sp1 to the allele with two 21-bp repeats was greater than that for the allele with one 21-bp repeat. As established with a reporter assay, plasmids containing zero or one repeat element had higher transcriptional activities than plasmids containing two repeat elements. Furthermore, fewer tandem repeats in the promoter of XRCC5 was associated with enhanced levels of the XRCC5 protein in bladder cancer patients. Although, in a case–control study, the different genotypes were not associated with the risk of bladder cancer, individuals not carrying the two tandem repeats allele had an increased risk of bladder cancer compared with those carrying the allele with two repeats. These results indicated that, at least in a population in southeastern China, this polymorphism in the promoter of XRCC5 could regulate the expression of XRCC5 and thereby contribute to susceptibility to bladder cancer. [Copyright &y& Elsevier]

• Genetic polymorphisms of 47 A-InDels in three ethnic groups were investigated. • The AGCU InDel 50 kit is polymorphic for human identification applications. • Genetic relationships among 34 populations were investigated. • An unusual phylogenetic pattern was displayed among the three groups. Insertion/deletion polymorphisms (InDels), which combine the desirable features of both short tandem repeats (STRs) and single-nucleotide polymorphisms (SNPs), have become widely used genetic markers for forensic investigations, anthropology and population genetics. The AGCU InDel 50 kit is a newly developed panel that contains 47 autosomal InDels (A-InDels), 2 Y-chromosomal InDels (Y-InDels) and Amelogenin and is designed to provide a higher discriminatory power in Chinese populations compared with the Qiagen DIPplex kit. In this study, 542 unrelated individuals were first genotyped to evaluate the forensic efficiency of this novel panel in three Chinese ethnicities (Hainan Han, Hainan Li and Zunyi Gelao groups). Additionally, genetic relationships among the three investigated populations (geographically close but linguistically different populations: Han and Li; geographically diverse but from the same language family: Li and Gelao) and 31 worldwide populations were analyzed using pairwise genetic distances, multidimensional scaling (MDS), phylogenetic tree, principal component analysis (PCA) and STRUCTURE. The combined powers of discrimination (CPD) for the Han, Li and Gelao groups were 0.999999999999999999635, 0.999999999999999997668 and 0.999999999999999999840, respectively, and the combined powers of exclusion (CPE) were 0.999715, 0.999283 and 0.999575, respectively. The genetic relationship between the Hainan Han and Zunyi Gelao groups was relatively closer than that between the Hainan Li and Zunyi Gelao groups, demonstrating that there was little gene communication between Li and Han living on Hainan Island as well as between Li and Gelao in the Tai-Kadai language family. The aforementioned results suggest that the AGCU InDel 50 kit is an effective tool that is appropriate for personal identification and population genetics. [ABSTRACT FROM AUTHOR]

Sudden cardiac death (SCD) describes the unexpected natural death from a cardiac cause within a short time period. Compelling evidence suggests the involvement of host genetic factors in SCD etiology. Identification of genetic variations predisposed to SCD enables genetic testing that may contribute to SCD diagnosis and risk stratification. Previous studies have suggested that dysregulation of pro-alpha2 chain of type I collagen, encoded by collagen type I alpha 2 chain ( COL1A2 ) gene, was involved in cardiac disorders such as myocardial infarction, hypertrophic cardiomyopathy and atherosclerosis. By using a candidate-gene-based approach, we evaluated the association of a 7-base pair (7-bp) indel polymorphism (rs3917) in the 3′UTR of COL1A2 with the risk of SCD in a Chinese population (79 SCD cases and 328 controls). Logistic regression analysis showed that the deletion allele of rs3917 significantly increased the risk of SCD [odds ratio (OR) = 1.82; 95% confidence interval (CI) = 1.08–3.06; P = 0.0159]. Further genotype-phenotype association analysis revealed that the deletion allele was markedly correlated with lower expression of COL1A2 in human myocardium tissues. The luciferase activity analysis in an in vitro reporter gene system suggested that rs3917 could regulate COL1A2 expression through interrupting the binding of miR-296-3p with COL1A2 in an allele-dependent manner, which in turn confer SCD risk. Our data provided initial evidence that rs3917 was highly relevant to SCD susceptibility, and this indel may become a potential marker for molecular diagnosis and genetic counseling of SCD. The replication of our studies and further functional studies are needed to validate our findings. [ABSTRACT FROM AUTHOR]

Sudden unexplained death (SUD) constitutes a part of the overall sudden death that can not be underestimated. Over the last years, genetic testing on SUD has revealed that inherited channelopathies might play important roles in the pathophysiology of this disease. Ryanodine receptor type-2 (RYR2) is a kind of ion channel extensively distributed in the sarcoplasmic reticulum (SR) of myocardium. Studies on RYR2 have suggested that either dysfunction or abnormal expression of it could lead to arrhythmia, which may cause cardiac arrest. In this study, we conducted a case-control study to evaluate the association of a 4-base pair (4-bp) Indel polymorphism (rs10692285) in the 3'UTR of RYR2 with the risk of SUD and sudden cardiac death induced by coronary heart disease (SCD-AS) in a Chinese population. Logistic regression analysis showed that the insertion allele of rs10692285 had significantly increased the risk of SUD [OR=2.03; 95% confidence interval (CI)=1.08-3.77; P=0.0161; statistical power=0.743]. No relevance was observed between rs10692285 and SCD-AS. Further genotype-phenotype association analysis suggested that the expression level of RYR2 in human myocardium tissues with the insertion allele was higher than that with the deletion allele at both mRNA and protein levels. Dual-Luciferase activity assay system was used to detect the effect of rs10692285 on the transcription activity of RYR2. As expected, the result indicated that the transcription activity of RYR2 with the ins/ins genotype was higher than that with the del/del genotype. Finally, in-silico prediction revealed that different alleles of rs10692285 could alter the local structure of RYR2 mRNA and microRNA (miRNA) binding. In summary, our findings provided evidence that rs10692285 might contribute to SUD susceptibility through affecting the expression of RYR2, which suggest that abnormal ion channel activity is very likely to be the underlying mechanism of SUD, but not for SCD-AS. Thus, rs10692285 may become a potential marker for molecular diagnosis and genetic counseling of SUD. [ABSTRACT FROM AUTHOR]