Genetic Polymorphisms and Forensic Efficiency of 16 X-chromosomal STR Loci for Sri Lankan Population

A new 16 X- short tandem repeat (STR) multiplex PCR system has recently been developed for Sr Lankans, though its applicability in evolutionary genetics and forensic investigations has not been thoroughly assessed. In this study, 838 unrelated individuals covering all four major ethnic groups (Sinhalese, Sri Lankan Tamils, Indian Tamils and Moors) in Sri Lanka were successfully genotyped using this new multiplex system. The results indicated a high forensic efficiency for the tested loci in all four ethnicities confirming its suitability for forensic applications of Sri Lankans. Allele frequency distribution of Indian Tamils showed subtle but statistically significant differences from those of Sinhalese and Moors, in contrast to frequency distributions previously reported for autosomal STR alleles. This suggest a sex biased demographic history among Sri Lankans requiring a separate X-STR allele frequency database for Indian Tamils. Substantial differences observed in the patterns of LD among the four groups demand the use of a separate haplotype frequency databases for each individual ethnicity. When analysed together with other 14 world populations, all Sri Lankan ethnicities except Indian Tamils clustered closely with populations from Indian Bhil tribe, Bangladesh and Europe reflecting their shared Indo-Aryan ancestry.

A Highly Polymorphic Panel Consisting of Microhaplotypes and Compound Markers with the NGS and Its Forensic Efficiency Evaluations in Chinese Two Groups

Novel genetic markers like microhaplotypes and compound markers show promising potential in forensic research. Based on previously reported single nucleotide polymorphism (SNP) and insertion/deletion (InDel) polymorphism loci, 29 genetic markers including 22 microhaplotypes and seven compound markers were identified. Genetic distributions of the 29 loci in five continental populations, Kazak and Mongolian groups in China were investigated. We found that the expected heterozygosity values of these 29 loci were >0.4 in these populations, indicating these loci were relatively high polymorphisms. Population genetic analyses of five continental populations showed that five loci displayed relatively high genetic variations among these continental populations and could be useful markers for ancestry analysis. In summary, the 29 loci displayed relatively high genetic diversities in continental populations and Chinese two groups and could be informative loci for forensic research.

Genetic analysis of DXS101and DXS6807 short tandem repeat (X-STR) in samples of Iraqi Arab male population

Back ground: X-chromosomal short tandem repeats (X-STRs) have assured to be informative and particular role in complex relationship testing. DXS6807 known as tetra nucleotides polymorphism representing eight alleles of 251-275 bp in length. DXS6807 is located in, at XP 22.2, at a genetic distance of more than 87 and 151 Cm of X-chromosome. DXS101 is located104.9–121 cM from the Xp-telomere (Xp-tel) corresponding to cytogenetic position in Xq21.33–Xq22.3. Objective: The aim of this present study investigates the allele frequency of two markers DXS101, DXS6807 and forensic efficiency parameters for sample of Arabic Iraqi males. Material and methods: The population of this study includes 200 males apparently healthy unrelated participants from different region of Baghdad city, their ages ranged between (20-50) years. The Genomic DNA extracted and purified successfully from blood samples. Results: The forensic efficiency parameters result for these markers were following: polymorphism information content (PIC) of 0.834708, power of discrimination (PD) in male 0.851750, Power of exclusion (PE) 0.698316, MEC Krüger0.511679, MEC Kishida 0.694890. The forensic efficiency parameters analyzing from Arabic population were Power of discrimination (PD) = 0.73405, Polymorphism information content (PIC) =0.69489, Power of exclusion (PE) =0.482879.MEC Krüger =0.511679, MEC Kishida = 0.694890. Conclusions: The information provided establish this X-linked microsatellite marker as a valuable strategy for forensic application. DXS101is and DXS6807 recently consider more stable and suitable forensic markers for forensic application.