Biology subjects

Cai, Y.

Publications and source records attributed to Cai, Y..

At least 127 records · Page 7Linked to original sources

bioRxiv2023

Assembly and analysis of the genome of Notholithocarpus densiflorus

Tanoak (Notholithocarpus densiflorus) is an evergreen tree in the Fagaceae family found in California and southern Oregon. Historically, tanoak acorns were an important food source for Native American tribes and the bark was used extensively in the leather tanning process. Long considered a disjunct relictual element of the Asian stone oaks (Lithocarpus spp.), phylogenetic analysis has determined that the tanoak is an example of convergent evolution. Tanoaks are deeply divergent from oaks (Quercus) of the Pacific Northwest and comprise a new genus with a single species. These trees are highly susceptible to sudden oak death (SOD), a plant pathogen (Phytophthora ramorum) that has caused widespread mortality of tanoaks. Here, we set out to assemble the genome and perform comparative studies among a number of individuals that demonstrated varying levels of susceptibility to SOD. First, we sequenced and de novo assembled a draft reference genome of N. densiflorus using co-barcoded library processing methods and an MGI DNBSEQ-G400 sequencer. To increase the contiguity of the final assembly, we also sequenced Oxford Nanopore (ONT) long reads to 30X coverage. To our knowledge, the draft genome reported here is one of the more contiguous and complete genomes of a tree species published until now, with a contig N50 of [~]1.2 Mb and a scaffold N50 of [~]2.1 Mb. In addition, we sequenced 11 genetically distinct individuals and mapped these onto the draft reference genome enabling the discovery of almost 25 million single nucleotide polymorphisms and [~]4.4 million small insertions and deletions. Finally, using co-barcoded data we were able to generate complete haplotype coverage of all 11 genomes.

genomics↗

bioRxiv2023

Enhancing Light-Sheet Fluorescence Microscopy Illumination Beams through Deep Design Optimization

Light sheet fluorescence microscopy (LSFM) provides the benefit of optical sectioning coupled with rapid acquisition times for imaging of tissue-cleared specimen. This allows for high-resolution 3D imaging of large tissue volumes. Inherently to LSFM, the quality of the imaging heavily relies on the characteristics of the illumination beam, with the notion that the illumination beam only illuminates a thin section that is being imaged. Therefore, substantial efforts are dedicated to identifying slender, non-diffracting beam profiles that can yield uniform and high-contrast images. An ongoing debate concerns the employment of the most optimal illumination beam; Gaussian, Bessel, Airy patterns and/or others. Comparisons among different beam profiles is challenging as their optimization objective is often different. Given that our large imaging datasets ([~]0.5TB images per sample) is already analyzed using deep learning models, we envisioned a different approach to this problem by hypothesizing that we can tailor the illumination beam to boost the deep learning models performance. We achieve this by integrating the physical LSFM illumination model after passing through a variable phase mask into the training of a cell detection network. Here we report that the joint optimization continuously updates the phase mask, improving the image quality for better cell detection. Our methods efficacy is demonstrated through both simulations and experiments, revealing substantial enhancements in imaging quality compared to traditional Gaussian light sheet. We offer valuable insights for designing microscopy systems through a computational approach that exhibits significant potential for advancing optics design that relies on deep learning models for analysis of imaging datasets.

scientific communication and education↗

bioRxiv2023

Comparing virtual staining artificial intelligence model performance on same-tissue versus serial-tissue sections based on CD3+ T-cell ground truth

Immunophenotyping via multi-marker assays significantly contributes to patient selection, therapeutic monitoring, biomarker discovery, and personalized treatments. Despite its potential, the multiplex immunofluorescence (mIF) technique faces adoption challenges due to technical and financial constraints. Alternatively, hematoxylin and eosin (H&E)-based prediction models of cell phenotypes can provide crucial insights into tumor-immune cell interactions and advance immunotherapy. Current methods mostly rely on manually annotated cell label ground truths, with limitations including high variability and substantial labor costs. To mitigate these issues, researchers are increasingly turning to digitized cell-level data for accurate in-situ cell type prediction. Typically, immunohistochemical (IHC) staining is applied to a tissue section serial to one stained with H&E. However, this method may introduce distortions and tissue section shifts, challenging the assumption of consistent cellular locations. Conversely, mIF overcomes these limitations by allowing for mIF and H&E staining on the same tissue section. Importantly, the multiplexing capability of mIF allows for a thorough analysis of the tumor microenvironment by quantifying multiple cell markers within the same tissue section. In this study, we introduce a Pix2Pix generative adversarial network (P2P-GAN)-based virtual staining model, using CD3+ T-cells in lung cancer as a proof-of-concept. Using an independent CD3 IHC-stained lung cohort, we demonstrate that the model trained with cell label ground-truth from the same tissue section as H&E staining performed significantly better in both CD3+ and CD3- T-cell prediction. Moreover, the model also displayed prognostic significance on a public lung cohort, demonstrating its potential clinical utility. Notably, our proposed P2P-GAN virtual staining model facilitates image-to-image translation, enabling further spatial analysis of the predicted immune cells, deepening our understanding of tumor-immune interactions, and propelling advancements in personalized immunotherapy. This concept holds potential for the prediction of other cell phenotypes, including CD4+, CD8+, and CD20+ cells.

immunology↗

bioRxiv2023

Paternal genomic resources from the YanHuang cohort suggested a Weakly-Differentiated Multi-source Admixture model for the formation of Hans founding ancestral lineages

The large-scale human genome revolution and rapidly advanced statistical innovation have updated our understanding of the fine-scale and complex genetic structure, the entire landscape of genetic diversity and the evolutionary trajectories of spatiotemporally different ancients and ethnolinguistically diverse modern populations. Recent ancient DNA research provided a detailed and complex admixture picture of ancient Europeans but limited insights into East Asians as the few available genomes. Y-chromosome variations in the male-specific regions, served as molecular archaeological tool, have unique evolutionary features that can be utilized to reconstruct the origin and subsequent interaction of ancient East Asian paternal lineages. We launched the YanHuang cohort using our designed highest-resolution capture sequencing panel to explore the detailed evolutionary trajectory of the Han Chinese, one of the largest ethnic groups in the world. We reported one of the largest uniparental genomic resources and observed multiple founding paternal lineages dominant in ancient western Eurasian, Siberian and East Asian participating in the formation of the gene pool of the Han Chinese. We identified fine-scale paternal genetic structure correlated with different patterns of ancient population interaction and geographical mountain barriers (Qinling-Huaihe line and Nanling Mountains), suggesting isolation-enhanced and admixture-introduced genetic differentiation enhanced the complexity of the Han Chinese genomic diversity. We observed a strong direct correlation between the frequency of multiple founding lineages of the Han Chinese and the proportion of subsistence-related ancestry sources related to western pastoralists, Holocene Mongolian Plateau people and ancient East Asians, reflecting the ancient migration events contributed to our identified patterns of Chinese paternal genomic diversity. We finally provided one novel and the most plausible admixture-by-admixture model, the Weakly-Differentiated Multi-Source Admixture model, as the major genetic mechanism to illuminate our observed pattern of complex interactions of multiple ancestral sources and landscape of the Han Chinese paternal genetic diversity. Generally, we presented one large-scale uniparental genomic resource from the YanHuang cohort, portrayed one novel admixture formation model and presented the entire genomic landscape with multiple ancestral sources related to ancient herders, hunter-gatherers and farmers who participated in the ancestral formation of the Han Chinese.

evolutionary biology↗

bioRxiv2023

Crossroads of assembling a moss genome: navigating contaminants and horizontal gene transfer in the moss Physcomitrellopsis africana

The first chromosome-scale reference genome of the rare narrow-endemic African moss Physcomitrellopsis africana is presented here. Assembled from 73x nanopore long reads and 163x BGI-seq short reads, the 414 Mb reference comprises 26 chromosomes and 22,925 protein-coding genes (BUSCO: C:94.8%[D:13.9%]). This genome holds two genes that withstood rigorous filtration of microbial contaminants, have no homolog in other land plants and are thus interpreted as resulting from two unique horizontal gene transfers from microbes. Further, Physcomitrellopsis africana shares 176 of the 273 published HGT candidates identified in Physcomitrium patens, but lacks 98 of these, highlighting that perhaps as many as 91 genes were acquired in P. patens in the last 40 million years following its divergence from its common ancestor with P. africana. These observations suggest rather continuous gene gains via HGT followed by potential losses, during the diversification of the Funariaceae. Our findings showcase both dynamic flux in plant HGTs over evolutionarily "short" timescales, alongside enduring impacts of successful integrations, like those still functionally maintained in extant Physcomitrellopsis africana. Furthermore, this study describes the informatic processes employed to distinguish contaminants from candidate HGT events. Article SummaryThe first draft genome of the rare South African endemic moss Physcomitrellopsis Africana is presented. The 414 Mb assembly contains 22,925 genes, including two uniquely horizontally transferred genes, but lacks 97 of the microbial genes previously identified in the closely related model, Physcomitrium patens - highlighting the dynamic role of HGT in the evolution of these moss genomes and loss. This study presents best practices for contamination detection and new insights into HGT identification.

genomics↗

bioRxiv2023

Fatty acid metabolism in neutrophils promotes lung damage and bacterial replication during tuberculosis.

Mycobacterium tuberculosis (Mtb) infection triggers a significant influx of neutrophils to the lungs, which is linked to tuberculosis (TB) severity. The mechanism by which Mtb infection induces neutrophillic inflammation remains unclear. Using a clinically relevant and hypervirulent Mtb strain from the W-Beijing family, HN878, we found that genes related to both glycolysis and fatty acid metabolism are upregulated in the lung neutrophils of susceptible mice. Similar effects in gene expression were observed in rabbits, and humans with pulmonary TB compared to healthy controls. Inhibiting glycolysis with 2-deoxy D-glucose (2-DG) exacerbated disease pathology, while fatty acid oxidation (FAO) inhibitor Etomoxir (ETO) improved outcomes by reducing weight loss, immunopathology, and bacterial replication within neutrophils in genetically susceptible mice. Notably, ETO reduced neutrophil production in the bone marrow and their recruitment to the lungs. ETO specifically restrained the recruitment of Ly6Glow/dim immature neutrophil population, which is elevated during disease progression and harbors the bulk of bacilli. In a transwell setup, we demonstrated that ETO dose-dependently inhibited neutrophil chemotaxis towards infected macrophages. In summary, our research highlights the crucial role of fatty acid metabolism in regulating neutrophilic inflammation during TB and provides a rationale for targeting immunometabolism of neutrophils for potential TB treatment.

immunology↗

bioRxiv2023

Single-cell impedance cytometry of anticancer drug-treated tumor cells exhibiting mitotic arrest state to apoptosis using low-cost silver-PDMS microelectrodes

Chemotherapeutic drugs such as paclitaxel and vinblastine interact with the microtubules, and thus induce complex cell states of mitosis arrest at the G2/M phase followed by apoptosis dependent on drug exposure time and concentration. Microfluidic impedance cytometry (MIC) as a label-free and high-throughput technology for single-cell analysis, has been applied for viability assay of cancer cells post drug exposure at fixed time and dosage, yet verification of this technique for varied tumor cell states after anticancer drug treatment remains vacant. Here we present a novel MIC device and for the first time perform impedance cytometry on carcinoma cells exhibiting progressive states of G2/M arrest followed by apoptosis related to drug concentration and exposure time, after treatments by paclitaxel and vinblastine, respectively. Our results from impedance cytometry reveal increased amplitude and negative phase shift at low frequency, as well as higher opacity for the Hela cells under G2/M mitotic arrest compared to the untreated cells. The cells under apoptosis, on the other hand, exhibit opposite changes in these electrical parameters. Therefore, the impedance features differentiate the Hela cells under progressive states post anticancer drug treatment. We also demonstrate that vinblastine poses a more potent drug effect than paclitaxel especially at low concentrations. Our device is fabricated with a unique sacrificial layer-free soft lithography process as compared to the existing MIC device, which gives rise to readily aligned parallel microelectrodes made of silver-PDMS embedded in PDMS channel sidewalls with one molding step. Our results uncover the potential of the MIC device, with a fairly simple and low-cost fabrication process, for cellular state screening in anticancer drug therapy.

cell biology↗

bioRxiv2023

High plasticity of ribosomal DNA organization in budding yeast

In eukaryotic genomes, ribosomal DNA (rDNA) generally resides as a highly repetitive and dynamic structure, making it difficult to study. Here, a synthetic rDNA array on chromosome III in budding yeast was constructed to serve as the sole source of rRNA. Utilizing the loxPsym site within each rDNA repeat and the Cre recombinase, we were able to reduce the copy number to as few as eight copies. Additionally, we constructed strains with two or three rDNA arrays, and found that the presence of multiple arrays did not affect the formation of a single nucleolus. Although alteration on the position and number of rDNA arrays did impact three-dimensional genome structure, the additional rDNA arrays had no deleterious influence on cell growth or transcriptomes. Together, this study sheds light on the high plasticity of rDNA organization and opens up opportunities for future rDNA engineering. HighlightsO_LIA method was established for efficient construction of synthetic rDNA arrays in budding yeast C_LIO_LIThe rDNA repeats in a haploid yeast can be reduced to as few as eight copies to support cell viability C_LIO_LIYeast cells with two or three DNA arrays on distinct chromosomes form a single nucleolus. C_LIO_LIDispersed rDNA arrays result in no deleterious influence on cell growth or transcriptomes. C_LI

synthetic biology↗

bioRxiv2023

KRAS inhibition activates an actionable CD24 do-not-eat-me signal in pancreas cancer

KRASG12C inhibitors (G12Ci) have produced encouraging, albeit modest and transient, clinical benefit in pancreatic ductal adenocarcinoma (PDAC). Identifying and targeting resistance mechanisms to G12Ci treatment is therefore crucial. To better understand the function of KRASG12C and possible G12Ci bypass mechanisms, we developed an autochthonous KRASG12C- driven PDAC model. Compared to the classical KRASG12D PDAC model, the G12C model exhibits slower tumor growth, yet similar histopathological and molecular features. Aligned with clinical experience, G12Ci treatment of KRASG12C tumors produced modest impact despite stimulating a hot tumor immune microenvironment. Immunoprofiling revealed that CD24, a dont eat me signal, is significantly upregulated on cancer cells upon G12Ci treatment. Blocking CD24 enhanced macrophage phagocytosis of cancer cells and significantly sensitized tumors to G12Ci treatment. Similar findings were observed in KRASG12D-driven PDAC. Together, this study reveals common and distinct oncogenic KRAS allele-specific biology and identifies a clinically actionable adaptive mechanism that may improve the efficacy of oncogenic KRAS inhibitor therapy in PDAC. SignificanceGeneration of an autochthonous KRASG12C-driven pancreatic cancer model enabled elucidation of specific effects of KRASG12C during tumor development, revealing CD24 as an actionable adaptive mechanism in cancer cells induced upon KRASG12C inhibition.

cancer biology↗

bioRxiv2023

Super-silencer perturbation by EZH2 and REST inhibition leads to large loss of chromatin interactions and reduction in cancer growth

Human silencers have been shown to exist and regulate developmental gene expression. However, the functional importance of human silencers needs to be elucidated, such as whether they can form "super-silencers" and whether they are linked to cancer progression. Here, through interrogating two putative silencer components of FGF18 gene, we found that two nearby silencers can cooperate via compensatory chromatin interactions to form a "super-silencer". Furthermore, double knockout of two silencers exhibited synergistic upregulation of FGF18 expression and changes of cell identity. To perturb the "super-silencers", we applied combinational treatment of an EZH2 inhibitor GSK343, and a REST inhibitor, X5050 ("GR"). We found that GR led to severe loss of TADs and loops, while the use of one inhibitor by itself only showed mild changes. Such changes in TADs and loops were associated with reduced CTCF and TOP2A mRNA levels. Moreover, GSK343 and X5050 synergistically upregulated super-silencer-controlled genes related to cell cycle, apoptosis and DNA damage, leading to anticancer effects both in vitro and in vivo. Overall, our data demonstrated the first example of a "super-silencer" and showed that combinational usage of GSK343 and X5050 to disrupt "super-silencers" could potentially lead to cancer ablation.

molecular biology↗

bioRxiv2023

Ancient farmer and steppe pastoralist-related founding lineages contributed to the complex landscape of episodes in the diversification of Chinese paternal lineages

Ancient DNA advances have reported the complex genetic history of Eurasians, but how the knowledge of ancient subsistence strategy shifts and population movements influenced the fine-scale paternal genetic structure in East Asia has not been assessed. Here, we reported one integrated Y-chromosome genomic database of 15,530 people, including 1753 ancient people and newly-reported 919 individuals genotyped using our recently-developed targeted sequencing YHSeqY3000 panel, to explore Chinese genomic diversity, population evolutionary tracts and their genetic formation mechanism. We identified four major ancient technological innovations and population movements that shaped the landscape of Chinese paternal lineages. First, the expansion of millet farmers and early East Asians from the Yellow River Basin carrying the major O2/D subclades promoted the formation of the Sino-Tibetan peoples major composition and accelerated the Tibetan Plateaus permanent occupation. Second, rice farmers dispersal from the Yangtze River Valley carrying O1 and some sublineages of O2 contributed significantly to Tai-Kadai, Austronesian, Hmong-Mien, Austroasiatic people and southern Han Chinese. Third, Siberian-related paternal lineages of Q and C originated and boomed from Neolithic hunter-gatherers from the Mongolian Plateau and the Amur River Basin and significantly influenced the gene pools of northern Chinese. Fourth, western Eurasian-derived J, G and R lineages initially spread with Yamnaya steppe pastoralists and other proto-Indo-European people and further widely dispersed via the trans-Eurasian cultural communication along the Eurasian Steppe and the ancient Silk Road, remaining genetic trajectories in northwestern Chinese. Our work provided comprehensive modern and ancient genetic evidence to illuminate the impact of population interaction from the ancient farmer or herder-based societies on the genetic diversity patterns of modern people, revised our understandings of ancestral sources of Chinese paternal lineages, underscored the scientific imperative of the large-scale genomic resources of dense spatiotemporal underrepresented sampling populations to understand human evolutionary history.

genetics↗

bioRxiv2023

Quantification of circulating tumor DNA using deep learning

Quantification of circulating tumor DNA (ctDNA) levels in blood enables non-invasive surveillance of cancer progression. Fragle is an ultra-fast deep learning-based method for ctDNA quantification directly from cell-free DNA fragment length profiles. We developed Fragle using low-pass whole genome sequence (lpWGS) data from multiple cancer types and healthy control cohorts, demonstrating high accuracy, and improved lower limit of detection in independent cohorts as compared to existing tumor-naive methods. Uniquely, Fragle is also compatible with targeted sequencing data, exhibiting high accuracy across both research and commercial targeted gene panels. We used this method to study longitudinal plasma samples from colorectal cancer patients, identifying strong concordance of ctDNA dynamics and treatment response. Furthermore, prediction of minimal residual disease in resected lung cancer patients demonstrated significant risk stratification beyond a tumor-naive gene panel. Overall, Fragle is a versatile, fast, and accurate method for ctDNA quantification with potential for broad clinical utility.

bioinformatics↗

bioRxiv2023

Reactivating and reorganizing activity-silent working memory: two distinct mechanisms underlying pinging the brain

Recent studies have proposed that visual information can be maintained in an activity-silent state during working memory (WM), which can be reactivated by task-irrelevant high-contrast visual impulses (i.e., "pinging the brain"). Although pinging the brain has become a popular tool for exploring activity-silent WM in recent years, its underlying mechanisms remain unclear. In the current study, we directly compared the behavioral consequences and neural reactivation effects of context-independent and context-dependent pings to distinguish the noise-reduction and target-interaction hypotheses of pinging the brain. At first, in a behavioral study, we found that, compared with the baseline condition (no ping), only the horizontal context-dependent pings impaired recall performance. In a follow-up electroencephalogram study, our neural decoding results showed that the context-independent pings reactivated activity-silent WM transiently without changing the original WM representations or recall performance. In contrast, the context-dependent pings reactivated activity-silent WM more durably and further reorganized WM information by decreasing the dynamics of items neural representations. Notably, only the reactivation strength of the context-dependent pings correlated with recall performance and was modulated by the location of memorized items, with neural representations only being reactivated when both items and pings were presented horizontally. Together, our results provided evidence for two distinct mechanisms underlying pinging the brain, and the pings context played a critical role in reactivating and reorganizing activity-silent WM.

neuroscience↗

bioRxiv2023

Conservation and divergence of regulatory architecture in nitrate-responsive plant gene circuits

Nitrogen is an essential element for all life processes in plants. As such, plant roots dynamically respond to nitrogen availability below-ground by executing a signaling and transcriptional cascade resulting in altered plant growth, optimized for nutrient uptake. The NIN-LIKE PROTEIN 7 (NLP7) transcription factor senses nitrogen and along with its closely related paralog NLP6, partially coordinates these transcriptional responses. While post-translational regulation of NLP6/7 is well established, its upstream transcriptional regulation remains understudied in Arabidopsis and other plant species. Here, we dissect a previously identified sub-circuit upstream of NLP6/7 in Arabidopsis and which was predicted to contain multiple multi-node feedforward loops suggestive of an optimized design principle of nitrogen transcriptional regulation. This sub-circuit comprises AUXIN RESPONSE FACTOR 18 (ARF18), ARF9, DEHYDRATION RESPONSE ELEMENT BINDING-PROTEIN 26 (DREB26), A NAC-DOMAIN CONTAINING PROTEIN 32 (ANAC032), NLP6 and NLP7 and their regulation of NITRITE REDUCTASE 1 (NIR1). Conservation and divergence of this circuit and their influence on N-dependent root system architecture are similarly assessed in Solanum lycopersicum. The specific binding sites of these factors within their respective promoters and their putative cis-regulatory architecture are identified. The direct or indirect nature of these interactions are validated in planta. The resulting models were genetically validated in varying concentrations of available nitrate by measuring the transcriptional output of the network revealing rewiring of nitrogen regulation across distinct plant lineages. Significance StatementNitrogen is a critical nutrient for plant growth and yield. While external N has facilitated modern agriculture, over-application of N-containing fertilizers has drastic ecological and environmental consequences. Here, we experimentally validate a six gene regulatory circuit with extensive feedforward loops identified to act upstream of the critical NIN-LIKE PROTEIN 6/7 transcription factors which regulates a nitrogen metabolic enzyme. Our results indicate conservation and divergence in these circuits between Arabidopsis and tomato despite the similar role of NLP7 in N-dependent changes in root system architecture. The resulting network models complement existing knowledge of NLP7 regulation by providing a framework for targeted transcriptional engineering to increase plant nitrogen use efficiency.

plant biology↗

bioRxiv2023

Sustained hippocampal theta-oscillations reflect experience-dependent learning in bidirectional temporal-order memory retrieval

Navigating within our neighborhood, learning a set of concepts, or memorizing a story, requires remembering the relationship between individual items that are presented sequentially. Theta activity in the mammalian hippocampus has been related to the encoding and recall of relational structures embedding episodic memories. However, how theta oscillations are involved in retrieving temporal order information in opposing directionality (forward vs backward) has not been characterized. Here, using intracranial recordings from 10 human epileptic patients of both genders with hippocampal electrodes, we tested the patients with a temporal order memory task in which they learned the spatial relationship among individual items arranged along a circular track and were tested on both forward-cued and backward-cued retrieval conditions. We found that sustained high-power oscillatory events in the hippocampal theta (2-8 Hz) band, as quantified by Pepisode rate, were higher for the backward conditions during the later stage but not in the earlier stage. The theta Pepisode results are consistent with the behavioral memory performance. In contrast, we observed a stronger effect of forward than backward retrieval for the gamma (30-70 Hz) Pepisode rate irrespective of stages. Our results revealed differential roles of theta vs. gamma oscillations in the retrieval of temporal order and how theta oscillations are specifically implicated in the learning process for efficient retrieval of temporal order memories under opposing directionality. Significance statementWhile the hippocampus is critical to link events into unitary episodes, the effect of repeated experiences, or learning, on these processes is not entirely clear. We discovered that hippocampal theta oscillation in humans is modulated by repeated experiences, which in turn increases the efficacy of backward-cued memory retrieval of temporal order. This study revealed an important physiological signature characterizing the role of experiences and learning in bidirectional temporal memory retrieval. Journal sectionBehavioral/Cognitive

neuroscience↗

bioRxiv2023

Malaria resistance-related biological adaptation and complex evolutionary footprints of Tai-Kadai people inferred from 796 genomes

Pathogen-host adaptative interaction and complex population demographical processes, including admixture, drift and Darwen selection, have considerably shaped the Neolithic-to-Modern Western Eurasian population structure and genetic susceptibility to modern human diseases. However, the genetic footprints of evolutionary events in East Asia keep unknown as the underrepresentation of genomic diversity and the design of large-scale population studies. We reported one aggregated database of genome-wide-SNP variations from 796 Tai-Kadai (TK) genomes, including Bouyei first reported here, to explore the genetic history, population structure and biological adaptative features of TK-speaking people from Southern China and Southeast Asia. We found geography-related population substructure among TK-speaking people using the state-of-the-art population genetic structure reconstruction techniques based on the allele frequency spectrum and haplotype-resolved phased fragments. We found that the Northern TK-speaking people from Guizhou harboured one TK-dominant ancestry maximised in Bouyei people, and the Southern one from Thailand obtained more influences from Southeast Asians and indigenous people. We reconstructed the fitted admixture models and demographic graphs, which showed that TK-speaking people received gene flow from ancient rice farmer-related lineages related to the Hmong-Mien and Austroasiatic people and Northern millet farmers associated with the Sino-Tibetan people. Biological adaptation focused on our identified unique TK lineages related to Bouyei showed many adaptive signatures conferring Malaria resistance and low-rate lipid metabolism. Further gene enrichment, the allele frequency distribution of derived alleles, and their correlation with the incidence of Malaria further confirmed that CR1 played an essential role in the resistance of Malaria in the ancient "Baiyue" tribes.

genetics↗

bioRxiv2023

Distinguished biological adaptation architecture aggravated population differentiation of Tibeto-Burman-speaking people inferred from 500 whole genome data from 39 populations

Tibeto-Burman (TB) people have tried to adapt to the hypoxic, cold and high-UV high-altitude Tibetan Plateau and complex disease exposure in the lowland wet and hot rainforest since the late Paleolithic period. However, the full landscape of genetic history and biological adaptation of geographically diverse TB people and their interaction mechanism remained unknown. We generated a whole-genome-based meta-database of 500 individuals from 39 TB populations from East Asia and Southeast Asia and presented a comprehensive landscape of genetic diversity, admixture history and differentiated adaptative features of geographically different TB people. We identified geography/language-related genetic differentiation among Tibetan Plateau, Tibetan-Yi-Corridor (TYC) and Southeast Asian TB people, consistent with their differentiated admixture process with incoming or indigenous ancestral source populations. A robust genetic connection between TYC people and ancient YR people supported the Northern origin hypothesis of TB people. We reported population substructure-related differentiated biological adaptative signatures between highland Tibetans and lowland TB people and between geographically different Lolo speakers. Highland adaptative EPAS1 and EGLN variants riched in Tibetans but lacked in TYC people whose adaptation is associated with the physical features and skin pigmentation (EDAR and SLC24A5), hepatic alcohol metabolism (ALDH9A1), regulation of cell-cell adhesion of muscle cells (CTNNA3) and immune/fat metabolism-related adaptative signature. TB-related genomic resources provided new insights into the genetic basis of phenotype differences and better reference for the anthropologically-informed sampling design in biomedical and genomic cohort research.

genetics↗

bioRxiv2023

The Multifaceted Effects of Short-Term Acute Hypoxia Stress: Insights into the tolerance mechanism of Propsilocerus akamusi (Diptera: Chironomidae)

Plenty of freshwater species, especially macroinvertebrates that are essential to the provision of numerous ecosystem functions, encountered higher mortality due to acute hypoxia. However, within the family Chironomidae, a wide range of tolerance to hypoxia/anoxia is displayed and Propsilocerus akamusi depends on this great endurance to become a dominant species in eutrophic lakes. To further understand how P. akamusi responds to acute hypoxic stress, we used multi-omics analysis in combination with histomorphological characteristics and physiological indicators. To evaluate enzyme activity, the transcriptome and metabolome, and histomorphological characteristics, we set up two groups: a control group (DO 8.4mg/L) and a hypoxic group (DO 0.39mg/L). With blue-black chromatin, cell tightness, cell membrane invagination, and the production of apoptotic vesicles, tissue cells displayed typical apoptotic features. While lactate dehydrogenase (LDH), (Alcohol dehydrogenase) ADH, catalase (CAT), and Na+/K+ -ATPase (NKA) activities were dramatically enhanced under hypoxic stress, glycogen content, and superoxide dismutase (SOD) activities were significantly reduced compared to the control group. The above results were further supported by the joint analysis of the transcriptome and metabolome, which further revealed that in addition to carbohydrates, including glycogen, the energy metabolism of the fatty acid, trehalose, and glyoxylate cycles is also included. Furthermore, we also revealed the ethanol tested in hypoxic stress should derive from symbiodinium of P akamusi. Understanding the processes which enable P. akamusi to survive lengthy periods of hypoxia in eutrophic lakes might help to design sensitive biomonitoring procedures, and this species has the potential to be used as an effective eutrophication indicator.

biophysics↗