Forensic Efficiency Estimation of a Homemade Six-Color Fluorescence Multiplex Panel and In-Depth Anatomy of the Population Genetic Architecture in Two Tibetan Groups.

The genetic information of the Chinese Tibetan group has been a long-standing research hotspot among population geneticists and archaeologists. Herein, 309 unrelated individuals from two Tibetan groups living in Qinghai Province, China (CTQ), and Tibet Autonomous Region, China (CTT), were successfully genotyped using a new homemade six-color fluorescence multiplex panel, which contained 59 autosomal deletion/insertion polymorphisms (au-DIPs), two mini short tandem repeats (miniSTRs), two Y-chromosomal DIPs, and one Amelogenin. The cumulative probability of matching and combined power of exclusion values for this new panel in CTQ and CTT groups were 1.9253E-27 and 0.99999729, as well as 1.5061E-26 and 0.99999895, respectively. Subsequently, comprehensive population genetic analyses of Tibetan groups and reference populations were carried out based on the 59 au-DIPs. The multitudinous statistical analysis results supported that Tibetan groups have close genetic affinities with East Asian populations. These findings showed that this homemade system would be a powerful tool for forensic individual identification and paternity testing in Chinese Tibetan groups and give us an important insight for further perfecting the genetic landscape of Tibetan groups.

Developmental Validation of the Novel Five-Dye-Labeled Multiplex Autosomal STR Panel and Its Forensic Efficiency Evaluation.

Short tandem repeats (STRs) are the most frequently used genetic markers in forensic genetics due to their high genetic diversities and abundant distributions in the human genome. Currently, the combined DNA index system is commonly incorporated into various commercial kits for forensic research. Some novel STRs that are different from the combined DNA index system were not only used to assess complex paternity cases but also could provide more genetic information and higher forensic efficiency in combination with those commonly used STRs. In this study, we validated forensic performance of a novel multiplex amplification STR panel to evaluate its sensitivity, species specificity, forensic application values, and so on. Obtained results revealed that the kit showed high sensitivity, and the complete allelic profile could be observed at 0.125 ng DNA sample. In addition, the kit possessed high species specificity, good tolerance to common inhibitors, and accurate genotyping ability. More importantly, STRs out of the kit displayed high discrimination power and probability of exclusion. To sum up, the novel kit presented in this study can be viewed as a promising tool for forensic human identification and complex paternity analysis.

Developmental validation study of a 32-plex STR direct amplification system for forensic reference samples.

The STRtyper-32G PCR Amplification Kit is a 6-dye multiplex system that combines the 30 autosomal STR loci with an Indel site (YIndel) and the sex-determinant locus Amelogenin. In addition to more loci, Master Mix has been optimized to amplify DNA on different substrates. The autosomal STR loci contained in this novel system meet the compatibility of requirements for databasing. In this study, the developmental validation study of the STRtyper-32G Kit followed the guidelines of SWGDAM (Scientific Working Group on DNA Analysis Methods), including PCR-based studies, species specificity, inhibitors, sensitivity, precision, repeatability, stutter, DNA mixtures, concordance studies, and population genetics studies. The validation results indicate that the new multiplex system is a robust tool for forensic database applications.

Gene flow and phylogenetic analyses of paternal lineages in the Yi-Luo valley using Y-STR genetic markers.

BACKGROUND: The Yi-Luo valley witnessed the most significant socio-political transformation of China and was deeply implicated in several enormous migrations of the Han population. However, little has been done to clarify its paternal genetic variation or phylogenetic relationship, particularly concerning the genetic evidence of their migrations. AIM: This study aims to uncover the population genetic characteristics in the Yi-Luo valley and provide genetic evidence for its people's migrations. SUBJECTS AND METHODS: Seventeen Y-STR loci included in the AmpFlSTR®Yfiler™ were typed in 2,314 individuals from seven different regions along the Yi-Luo valley. A multidimensional scaling plot and neighbor-joining tree were constructed for nationwide genetic comparisons. Y-haplogroup frequencies and migration rates were estimated among the studied populations. Gene flows were detected by different migration models and directions. RESULTS: The predicted Y-haplogroups demonstrated the predominance of O2a2. Genetic affinities were observed among Han, Hakka, Danmin, and Bai. Anhui was shown to be the most crucial transfer spot for the Hakkas when they moved out of the Central Plains to South China. CONCLUSIONS: This study reveals the genetic landscape of paternal lineages living in the Yi-Luo valley and enriches our understanding of the great migration in Chinese history.

Forensic and phylogenetic analyses of populations in the Tibetan-Yi corridor using 41 Y-STRs.

Y-chromosome haplotypes of 527 non-related males (176 Han, 186 Tibetan, and 165 Yi) in the Tibetan-Yi corridor were analyzed using SureID® PathFinder Plus. In the populations of Han, Tibetans, and Yi, the haplotype diversity was 0.9989, 0.9981, and 0.9993, respectively, and the discrimination capacity was 0.9148, 0.8925, and 0.9576, respectively. Phylogenetic relationships among 12 studied ethnic groups and 7 other ethnic groups in the Tibetan-Yi corridor were investigated. Both multi-dimensional scaling analysis and phylogenetic reconstructions indicated that Tibetans appeared separated from the Han and Yi ethnic groups in the Tibetan-Yi corridor. Their genetic homogeneity or heterogeneity has not entirely been affected by their geographical distance and linguistic origin.