The genomic origins of the Bronze Age Tarim Basin mummies.

The identity of the earliest inhabitants of Xinjiang, in the heart of Inner Asia, and the languages that they spoke have long been debated and remain contentious1. Here we present genomic data from 5 individuals dating to around 3000-2800 BC from the Dzungarian Basin and 13 individuals dating to around 2100-1700 BC from the Tarim Basin, representing the earliest yet discovered human remains from North and South Xinjiang, respectively. We find that the Early Bronze Age Dzungarian individuals exhibit a predominantly Afanasievo ancestry with an additional local contribution, and the Early-Middle Bronze Age Tarim individuals contain only a local ancestry. The Tarim individuals from the site of Xiaohe further exhibit strong evidence of milk proteins in their dental calculus, indicating a reliance on dairy pastoralism at the site since its founding. Our results do not support previous hypotheses for the origin of the Tarim mummies, who were argued to be Proto-Tocharian-speaking pastoralists descended from the Afanasievo1,2 or to have originated among the Bactria-Margiana Archaeological Complex3 or Inner Asian Mountain Corridor cultures4. Instead, although Tocharian may have been plausibly introduced to the Dzungarian Basin by Afanasievo migrants during the Early Bronze Age, we find that the earliest Tarim Basin cultures appear to have arisen from a genetically isolated local population that adopted neighbouring pastoralist and agriculturalist practices, which allowed them to settle and thrive along the shifting riverine oases of the Taklamakan Desert.

Potential Effects of Orally Ingesting Polyethylene Terephthalate Microplastics on the Mouse Heart.

Polyethylene terephthalate microplastics (PET MPs) are widespread in natural environment, and can enter organisms and accumulate in the body, but its toxicity has not been well studied. Therefore, in order to investigate the toxic effects of PET microplastics on mammals, this study investigated the toxic effects of PET MPs on ICR mice and H9C2 cells by different treatment groups. The results indicated the cardiac tissue of mice in the PET-H (50 µg/mL) group showed significant capillary congestion, myocardial fiber breakage, and even significant fibrosis compared to the PET-C (control) group (P < 0.01). Results of the TUNEL assay demonstrated significant apoptosis in myocardial tissue in the PET-H and PET-M (5 µg/mL) groups (P < 0.01). Meanwhile, Western blotting showed increased expression of the apoptosis-related protein Bax and decreased expression of PARP, caspase-3, and Bcl-2 proteins in both myocardial tissues and H9C2 cells. In addition, flow cytometry confirmed that PET MPs decreased the mitochondrial membrane potential and apoptosis in H9C2 cells; however, this trend was reversed by N-acetylcysteamine application. Moreover, PET MP treatment induced the accumulation of reactive oxygen species (ROS) in H9C2 cells, while the MDA level in the myocardial tissue was elevated, and the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) were decreased (P < 0.01), indicating a change in the redox environment. In conclusion, PET MPs promoted cardiomyocyte apoptosis by inducing oxidative stress and activating mitochondria-mediated apoptotic processes, ultimately leading to myocardial fibrosis. This study provides ideas for the prevention of PET MP toxicity and promotes thinking about enhancing plastic pollution control.

Comparative analysis of DNA extraction protocols for ancient soft tissue museum samples.

DNA studies of endangered or extinct species often rely on ancient or degraded remains. The majority of ancient DNA (aDNA) extraction protocols focus on skeletal elements, with skin and hair samples rarely explored. Similar to that found in bones and teeth, DNA extracted from historical or ancient skin and fur samples is also extremely fragmented with low endogenous content due to natural degradation processes. Thus, the development of effective DNA extraction methods is required for these materials. Here, we compared the performance of two DNA extraction protocols (commercial and custom laboratory aDNA methods) on hair and skin samples from decades-old museum specimens to Iron Age archaeological material. We found that apart from the impact sample-specific taphonomic and handling history has on the quantity and quality of DNA preservation, skin yielded more endogenous DNA than hair of the samples and protocols tested. While both methods recovered DNA from ancient soft tissue, the laboratory method performed better overall in terms of DNA yield and quality, which was primarily due to the poorer performance of the commercial binding buffer in recovering aDNA.

Denisovan DNA in Late Pleistocene sediments from Baishiya Karst Cave on the Tibetan Plateau.

A late Middle Pleistocene mandible from Baishiya Karst Cave (BKC) on the Tibetan Plateau has been inferred to be from a Denisovan, an Asian hominin related to Neanderthals, on the basis of an amino acid substitution in its collagen. Here we describe the stratigraphy, chronology, and mitochondrial DNA extracted from the sediments in BKC. We recover Denisovan mitochondrial DNA from sediments deposited ~100 thousand and ~60 thousand years ago (ka) and possibly as recently as ~45 ka. The long-term occupation of BKC by Denisovans suggests that they may have adapted to life at high altitudes and may have contributed such adaptations to modern humans on the Tibetan Plateau.