Detection of blood and DNA traces after thermal exposure: a critical appraisal

Forensic performance of 30 InDels included in the Investigator DIPplex system in Miao population and comprehensive genetic relationship in China Abstract Binary markers of insertion and deletion (InDel) play an important role in forensic personal identification, parentage testing, and individual ancestry inference. We first genotyped 30 InDels included in the Investigator DIPplex in 403 unrelated healthy Zunyi Miao people and analyzed the genetic polymorphisms, as well as explored the genetic relationship between Miao and 32 Chinese reference populations. No departures from the HWE were observed. The combined power of discrimination and the combined probability of exclusion were 0.99999999998 and 0.9884, respectively. Forensic parameters demonstrated that 30 markers are polymorphic and informative in the Zunyi Miao population and can be used as a tool for forensic personal identification and parentage testing. Allele frequency divergence analysis found that 12 out of 30 displaying high allele frequency difference between Turkic-speaking populations and other Chinese populations can be used as candidates of ancestry informative markers for ancestry inference of sub-population in East Asia. Population genetic parameters in the comprehensive population comparison among 33 Chinese populations indicated that our studied Hmong-Mien-speaking Miao has a close genetic relationship with geographically adjacent Enshi Tujia and genetically differentiate from Turkic-speaking populations.

Genetic polymorphisms of new 22 autosomal STR loci in the Mongolian ethnic group Abstract The Microreader™ 23SP ID System is a novel STR kit, but there are no Mongolian data related to this kit. In this study, allelic frequencies and forensic parameters were obtained from 505 unrelated healthy Mongolians. These samples were amplified using the kit. The dataset successfully passed quality control after being submitted to STRidER (STRidER dataset reference STR000198). A total of 264 alleles were observed, with corresponding allelic frequencies ranged from 0.001 to 0.378. The combined power of discrimination (CPD) and combined probability of exclusion (CPE) of the 22 autosomal STR loci were 0.999999999999999999999999999217318 and 0.999999999776042, respectively. Furthermore, population differentiation comparisons involving previously reported groups were conducted.

Genetic characteristics of 23 Y-chromosomal STRs in the Kinh population in Northern Vietnam Abstract We collected and analysed the genetic characteristics of 23 Y-STR data of 200 unrelated Kinh individuals living in the North of Vietnam. Haplotype frequencies and forensic parameters were calculated, showing high discrimination value. Population comparison analysis was performed to determine the genetic relationship with neighbouring ethnicities, in particular with Thai and Han populations.

Genetic data for PowerPlex 21™ autosomal and PowerPlex 23 Y-STR™ loci from population of the state of Uttar Pradesh, India Abstract In the present study, the statistical forensic parameters were evaluated for the loci present in PowerPlex 21 autosomal and PowerPlex 23 Y-STR multiplex systems in 168 unrelated individuals living in the state of Uttar Pradesh, India. The combined discrimination power (CPD) and combined exclusion power (CPE) was 1 and 0.999999 respectively for all 20 autosomal STR loci. Penta E showed the greatest (0.980) and CSF1PO showed the lowest (0.855) power of discrimination in the studied population. The haplotype diversity for 23 Y-STR loci was observed to be 0.999. The study also presents the first global report on polymorphism on D1S1656, D6S1043 and D12S391 autosomal STR loci in the Indian population. The resulting data revealed that these STR multiplex systems are highly polymorphic and can be used for forensic purposes.

Forensic features and genetic structure of 23 autosomal STRs in Artux Turkic-speaking population residing in southwestern Xinjiang Uyghur Autonomous Region Abstract Autosomal short tandem repeats (STRs) are viewed as the gold standard in forensic individual identification and parentage testing. The Huaxia Platinum System contains 23 autosomal markers along with rs2032678 (Yindel) and amelogenin. Here, we genotyped 23-STRs in the southwestern Xinjiang Uyghur residing in the Artux Region and assessed the allele frequency and forensic statistical parameters. All investigated STRs are in conformity with the Hardy-Weinberg equilibrium with an effective combined power of discrimination (0.99999999999999999999999999992) and cumulative probability of exclusion (0.9999999997) in the Artux Uyghur population. Population comparisons among 54 worldwide populations via PCA and MDS indicate that the Artux Uyghur population has a close genetic relationship with geographically distinct Uyghurs and Kazakh groups than other East Asians or Eurasians. Genetic ancestry component dissection among 2198 individuals from Sinitic, Turkic, and Tibeto-Burman language groups further demonstrates the genetic homogeneity within the Turkic language family and apparent genetic heterogeneity among other language groups.

Population genetic data of 20 insertion-null allele markers in the Andalusian population Abstract Genetic data from 21 autosomal insertion-null (INNULs) markers found in the InnoTyper® 21 Human DNA Analysis (InnoGenomics®) was evaluated in 190 unrelated individuals from Andalusia. Allele frequencies and forensic parameters were estimated for the 20 INNULs. All loci were in Hardy-Weinberg equilibrium in the study population after Bonferroni correction and showed no signs of linkage between them. The combined power of discrimination and the power of exclusion for the 20 INNULs were 1–7.42352 × 10−9 and 93.60946%, respectively. These data might be useful for the research of population genetics and for individual identification and paternity testing in forensic science.

Haplotype data for 17 Y-STR loci in the population of Himachal Pradesh, India Abstract We report here the data of Y chromosome haplotypes of 259 unrelated males from the population of Himachal Pradesh, India, using the Yfiler® multiplex kit. A total of 188 haplotypes were detected, out of which 148 were unique. Three samples showed bi-allelic pattern on locus DYS448. The observed genetic diversity and discrimination capacity were 0.996 and 0.73, respectively. In order to compare the genetic distance of the studied population with the published populations, multidimensional scaling (MDS) plot was constructed. The reported data is expected to be valuable for both forensic and population genetics.

The effects of different sampling techniques on peripheral post mortem tryptase levels: a recommended sampling method Abstract Different sampling techniques can impact on post mortem tryptase levels. A previous study demonstrated significantly lower femoral post mortem total tryptase levels in samples collected via transcutaneous aspiration compared with directly sampling during internal examination. However, an outlier with high tryptase level was noted in one transcutaneous aspiration sample. This 6-month prospective study compared total post mortem tryptase levels between 21 paired aspirated venous and arterial femoral blood samples, and 19 paired aspirated and cutdown femoral venous blood samples in non-anaphylactic deaths only. No statistical differences were demonstrated between the different sampling methods. However, four outlier cases with higher tryptase levels in aspirated arterial and femoral cutdown samples compared with aspirated venous femoral samples were noted. The reasons for the outliers may be due to the bloods collected from these two methods being contaminated by central arterial and venous blood with high tryptase levels respectively. None of the aspirated venous femoral post mortem tryptase levels were above recognized post mortem tryptase cutoff to diagnose anaphylaxis. This study recommends aspirating blood samples from a clamped femoral/external iliac vein for post mortem tryptase analysis should be defined as the gold standard. Further study using the recommended sampling method on post mortem tryptase levels in non-anaphylactic and anaphylactic cases is warranted.

Studies of hTERT DNA methylation assays on the human age prediction Abstract As an important aspect of epigenetics, DNA methylation has been proven to be suitable for forensic DNA analysis. By detecting changes in DNA methylation, it is desirable to construct a model of age patterns associated with it to infer the age of the individual. The hTERT gene methylation is closely related to tumors, but there are few reports on the relationship between hTERT gene promoter methylation and age. In this study, we utilized the methylation-specific polymerase chain reaction and real-time PCR (relative quantification and absolute quantification) approach to explore the connection between hTERT DNA methylation and age prediction. We fit three models for age prediction based on methylation assay for 90 blood samples from donors aged 1–79 years old. Among them, the model of absolute quantification of real-time enabled the age prediction with R2 = 0.9634. We verified the linear regression model with a validation set of 30 blood samples where prediction average error was 4.29 years. Generally, this reliable method improves the DNA methylation analysis of forensic samples.