Optimization and Developmental Validation of 38-plex InDel Panel for Ancestry Inference.

OBJECTIVES: The previously established 38-plex InDel system was optimized and its performance was validated according to the Scientific Working Group on DNA Analysis Method (SWGDAM) application guidelines. The ancestry inference accuracy of individuals from East Asian, European, African and mixed populations was verified. METHODS: DNA standard sample 9947A was used as the template to establish the optimal amplification conditions by adjusting primer balance, Mg2+ final concentration and optimizing PCR thermal cycle parameters and amplification volume. The allelic dropout, nonspecific amplification and whether the origin of the inferred samples matched the known information were compared to evaluate the performance of this system. RESULTS: The optimal dosage of this system was 0.125-2 ng DNA template. The results of InDel typing were accurate, the amplification equilibrium was good, and the species specificity was good. This system showed certain tolerance to DNA samples including the inhibitor such as hemoglobin (≤80 µmol/L), indigo (≤40 mmol/L), calcium ion (≤1.0 mmol/L), and humic acid (≤90 ng/µL). The system enabled the direct amplification of DNA from saliva and blood on filter paper, and the results of ethnic inference were accurate. The system successfully detected the mixed DNA sample from two individuals. The test results of the system for common biological materials in practical cases were accurate. CONCLUSIONS: The results of the 38-plex InDel system are accurate and reliable, and the performance of the system meets the requirement of the SWGDAM guidelines. This system can accurately differentiate the ancestry origins of individuals from African, European, East Asian, and Eurasian populations and can be implemented in forensic practice.

[A genetic sub-structure study of the Tibetan population in Southwest China].

Tibetan is a typical ethnic minority population in Southwest China, which can be divided into U-Tsang, Kham, Amdo, Jiarong and other sub-populations. However, the genetic structure of these sub-populations has not been comprehensively analyzed, especially from the perspective of paternal and maternal lineages. Based on genetic markers of autosomes, the Y chromosome and mitochondria, we studied four Tibetan populations (the U-Tsang population in Tibet Autonomous Region; the Kham population in Garze, Sichuan province; the Amdo population in Qinghai province and the Jiarong population in Aba, Sichuan province) to interpret their genetic structure. The mini-sequencing technology was used to detect the genotype of each maker. Meanwhile, the PowerPlex ?Y23 and DNA Typer TM Y26 kit were applied to genotype Y-STRs. Subsequently, the genetic structure was analyzed by heatmap and principal component analysis, ancestry component, haplogroup frequency, network map and multi-dimensional scaling analysis. The results showed that the four Tibetan populations could be divided into three sets based on the autosomal and Y-chromosomal genetic markers, in which set 1 was the U-Tsang population in the Tibetan Plateau, set 2 comprised of the Kham and Amdo populations in the surrounding areas of the plateau, and set 3 was the Jiarong population that resided in the Tibetan and Yi Corridor. No significant difference was observed in mitochondrial genetic markers among four Tibetan populations. In general, multi-category genetic information provides a new comprehensive insight into the Tibetan sub-population.

Copper-mediated direct thiolation of aryl C-H bonds with disulfides.

An efficient copper-mediated ortho-C(sp2)-H thiolation of aromatic amides directed by a novel directing group [4-chloro-2-(1H-pyrazol-1-yl)phenyl]amine has been developed without the need of other additives or oxidants, allowing for an increased usefulness. With the high compatibility of sterically demanding substrates, this reaction is scalable and can tolerate a wide scope of functional groups to provide alkyl and aryl thioethers in good to excellent yields (up to 93%). Furthermore, the protocol has been successfully implemented for the selenylation as well.

Organocatalytic enantioselective ß-functionalization of aldehydes by oxidation of enamines and their application in cascade reactions.

Iminium catalysis, involving the transformation of iminium ions to enamines, has been extensively studied in the context of a number of organic processes. However, the reverse of this process involving conversion of enamines to iminium species has not been realized. Here, we describe a new transformation-'oxidative enamine catalysis'-in which direct oxidation of an enamine occurs to generate an iminium species. We show that the use of o-iodoxybenzoic acid as an oxidant in the presence of a secondary amine catalyst serves as effective system for promoting rapid conversion of enamines to iminium ions. The preparative power of this process has been demonstrated in the context of direct asymmetric ß-functionalization of simple aldehydes. Moreover, a variety of enantioselective cascade transformations, including triple and quadruple cascades, have been developed for the 'one-pot' synthesis of versatile chiral building blocks and structural frameworks starting with simple aldehydes.