RESUMEN
Dysbiosis of gut microbiota is associated with many pathologies, yet host factors modulating microbiota remain unclear. Interstitial cystitis/bladder pain syndrome (IC/BPS) is a debilitating condition of chronic pelvic pain often with comorbid urinary dysfunction and anxiety/depression, and recent studies find fecal dysbiosis in patients with IC/BPS. We identified the locus encoding acyloxyacyl hydrolase, Aoah, as a modulator of pelvic pain severity in a murine IC/BPS model. AOAH-deficient mice spontaneously develop rodent correlates of pelvic pain, increased responses to induced pelvic pain models, voiding dysfunction, and anxious/depressive behaviors. Here, we report that AOAH-deficient mice exhibit dysbiosis of gastrointestinal (GI) microbiota. AOAH-deficient mice exhibit an enlarged cecum, a phenotype long associated with germ-free rodents, and a "leaky gut" phenotype. AOAH-deficient ceca showed altered gene expression consistent with inflammation, Wnt signaling, and urologic disease. 16S sequencing of stool revealed altered microbiota in AOAH-deficient mice, and GC-MS identified altered metabolomes. Cohousing AOAH-deficient mice with wild-type mice resulted in converged microbiota and altered predicted metagenomes. Cohousing also abrogated the pelvic pain phenotype of AOAH-deficient mice, which was corroborated by oral gavage of AOAH-deficient mice with stool slurry of wild-type mice. Converged microbiota also alleviated comorbid anxiety-like behavior in AOAH-deficient mice. Oral gavage of AOAH-deficient mice with anaerobes cultured from IC/BPS stool resulted in exacerbation of pelvic allodynia. Together, these data indicate that AOAH is a host determinant of normal gut microbiota, and dysbiosis associated with AOAH deficiency contributes to pelvic pain. These findings suggest that the gut microbiome is a potential therapeutic target for IC/BPS.
Asunto(s)
Hidrolasas de Éster Carboxílico , Cistitis Intersticial , Microbioma Gastrointestinal , Dolor Pélvico , Animales , Humanos , Hidrolasas de Éster Carboxílico/genética , Hidrolasas de Éster Carboxílico/metabolismo , Cistitis Intersticial/metabolismo , Modelos Animales de Enfermedad , Disbiosis/complicaciones , Disbiosis/metabolismo , Microbioma Gastrointestinal/genética , Microbioma Gastrointestinal/fisiología , Inflamación/metabolismo , Dolor Pélvico/metabolismo , Dolor Pélvico/fisiopatología , Vejiga Urinaria/metabolismo , RatonesRESUMEN
BACKGROUND: Diet affects the human gastrointestinal microbiota. Blood and urine samples have been used to determine nutritional biomarkers. However, there is a dearth of knowledge on the utility of fecal biomarkers, including microbes, as biomarkers of food intake. OBJECTIVES: This study aimed to identify a compact set of fecal microbial biomarkers of food intake with high predictive accuracy. METHODS: Data were aggregated from 5 controlled feeding studies in metabolically healthy adults (n = 285; 21-75 y; BMI 19-59 kg/m2; 340 data observations) that studied the impact of specific foods (almonds, avocados, broccoli, walnuts, and whole-grain barley and whole-grain oats) on the human gastrointestinal microbiota. Fecal DNA was sequenced using 16S ribosomal RNA gene sequencing. Marginal screening was performed on all species-level taxa to examine the differences between the 6 foods and their respective controls. The top 20 species were selected and pooled together to predict study food consumption using a random forest model and out-of-bag estimation. The number of taxa was further decreased based on variable importance scores to determine the most compact, yet accurate feature set. RESULTS: Using the change in relative abundance of the 22 taxa remaining after feature selection, the overall model classification accuracy of all 6 foods was 70%. Collapsing barley and oats into 1 grains category increased the model accuracy to 77% with 23 unique taxa. Overall model accuracy was 85% using 15 unique taxa when classifying almonds (76% accurate), avocados (88% accurate), walnuts (72% accurate), and whole grains (96% accurate). Additional statistical validation was conducted to confirm that the model was predictive of specific food intake and not the studies themselves. CONCLUSIONS: Food consumption by healthy adults can be predicted using fecal bacteria as biomarkers. The fecal microbiota may provide useful fidelity measures to ascertain nutrition study compliance.
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Dieta , Ingestión de Alimentos , Heces/microbiología , Adulto , Anciano , Biomarcadores , Microbioma Gastrointestinal , Humanos , Persona de Mediana Edad , Adulto JovenRESUMEN
Whole-genome assemblies of 19 placental mammals and two outgroup species were used to reconstruct the order and orientation of syntenic fragments in chromosomes of the eutherian ancestor and six other descendant ancestors leading to human. For ancestral chromosome reconstructions, we developed an algorithm (DESCHRAMBLER) that probabilistically determines the adjacencies of syntenic fragments using chromosome-scale and fragmented genome assemblies. The reconstructed chromosomes of the eutherian, boreoeutherian, and euarchontoglires ancestor each included >80% of the entire length of the human genome, whereas reconstructed chromosomes of the most recent common ancestor of simians, catarrhini, great apes, and humans and chimpanzees included >90% of human genome sequence. These high-coverage reconstructions permitted reliable identification of chromosomal rearrangements over â¼105 My of eutherian evolution. Orangutan was found to have eight chromosomes that were completely conserved in homologous sequence order and orientation with the eutherian ancestor, the largest number for any species. Ruminant artiodactyls had the highest frequency of intrachromosomal rearrangements, and interchromosomal rearrangements dominated in murid rodents. A total of 162 chromosomal breakpoints in evolution of the eutherian ancestral genome to the human genome were identified; however, the rate of rearrangements was significantly lower (0.80/My) during the first â¼60 My of eutherian evolution, then increased to greater than 2.0/My along the five primate lineages studied. Our results significantly expand knowledge of eutherian genome evolution and will facilitate greater understanding of the role of chromosome rearrangements in adaptation, speciation, and the etiology of inherited and spontaneously occurring diseases.
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Cromosomas/ultraestructura , Euterios/genética , Evolución Molecular , Algoritmos , Animales , Linaje de la Célula , Puntos de Rotura del Cromosoma , Biología Computacional/métodos , Reordenamiento Génico , Genoma , Genoma Humano , Humanos , Hibridación Fluorescente in Situ , Filogenia , Programas Informáticos , SinteníaRESUMEN
For 10,000 years pigs and humans have shared a close and complex relationship. From domestication to modern breeding practices, humans have shaped the genomes of domestic pigs. Here we present the assembly and analysis of the genome sequence of a female domestic Duroc pig (Sus scrofa) and a comparison with the genomes of wild and domestic pigs from Europe and Asia. Wild pigs emerged in South East Asia and subsequently spread across Eurasia. Our results reveal a deep phylogenetic split between European and Asian wild boars â¼1 million years ago, and a selective sweep analysis indicates selection on genes involved in RNA processing and regulation. Genes associated with immune response and olfaction exhibit fast evolution. Pigs have the largest repertoire of functional olfactory receptor genes, reflecting the importance of smell in this scavenging animal. The pig genome sequence provides an important resource for further improvements of this important livestock species, and our identification of many putative disease-causing variants extends the potential of the pig as a biomedical model.
Asunto(s)
Genoma/genética , Filogenia , Sus scrofa/clasificación , Sus scrofa/genética , Animales , Demografía , Modelos Animales , Datos de Secuencia Molecular , Dinámica PoblacionalRESUMEN
One of the most difficult problems in modern genomics is the assembly of full-length chromosomes using next generation sequencing (NGS) data. To address this problem, we developed "reference-assisted chromosome assembly" (RACA), an algorithm to reliably order and orient sequence scaffolds generated by NGS and assemblers into longer chromosomal fragments using comparative genome information and paired-end reads. Evaluation of results using simulated and real genome assemblies indicates that our approach can substantially improve genomes generated by a wide variety of de novo assemblers if a good reference assembly of a closely related species and outgroup genomes are available. We used RACA to reconstruct 60 Tibetan antelope (Pantholops hodgsonii) chromosome fragments from 1,434 SOAPdenovo sequence scaffolds, of which 16 chromosome fragments were homologous to complete cattle chromosomes. Experimental validation by PCR showed that predictions made by RACA are highly accurate. Our results indicate that RACA will significantly facilitate the study of chromosome evolution and genome rearrangements for the large number of genomes being sequenced by NGS that do not have a genetic or physical map.
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Algoritmos , Cromosomas/genética , Genoma/genética , Genómica/métodos , Animales , Antílopes/genética , Bovinos , Mapeo Cromosómico/métodos , Evolución Molecular , Reordenamiento Génico/genética , Humanos , Reproducibilidad de los Resultados , Análisis de Secuencia de ADN/métodosRESUMEN
Screening agrochemicals and pharmaceuticals for potential liver toxicity is required for regulatory approval and is an expensive and time-consuming process. The identification and utilization of early exposure gene signatures and robust predictive models in regulatory toxicity testing has the potential to reduce time and costs substantially. In this study, comparative supervised machine learning approaches were applied to the rat liver TG-GATEs dataset to develop feature selection and predictive testing. We identified ten gene biomarkers using three different feature selection methods that predicted liver necrosis with high specificity and selectivity in an independent validation dataset from the Microarray Quality Control (MAQC)-II study. Nine of the ten genes that were selected with the supervised methods are involved in metabolism and detoxification (Car3, Crat, Cyp39a1, Dcd, Lbp, Scly, Slc23a1, and Tkfc) and transcriptional regulation (Ablim3). Several of these genes are also implicated in liver carcinogenesis, including Crat, Car3 and Slc23a1. Our biomarker gene signature provides high statistical accuracy and a manageable number of genes to study as indicators to potentially accelerate toxicity testing based on their ability to induce liver necrosis and, eventually, liver cancer.
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Agroquímicos/toxicidad , Enfermedad Hepática Inducida por Sustancias y Drogas/diagnóstico , Marcadores Genéticos , Hígado/efectos de los fármacos , Aprendizaje Automático Supervisado , Algoritmos , Animales , Enfermedad Hepática Inducida por Sustancias y Drogas/genética , Regulación de la Expresión Génica/efectos de los fármacos , Masculino , Análisis de Secuencia por Matrices de Oligonucleótidos , RatasRESUMEN
Epithelial ovarian cancer (OC) is the most deadly cancer of the female reproductive system. To date, there is no effective screening method for early detection of OC and current diagnostic armamentarium may include sonographic grading of the tumor and analyzing serum levels of tumor markers, Cancer Antigen 125 (CA-125) and Human epididymis protein 4 (HE4). Microorganisms (bacterial, archaeal, and fungal cells) residing in mucosal tissues including the gastrointestinal and urogenital tracts can be altered by different disease states, and these shifts in microbial dynamics may help to diagnose disease states. We hypothesized that the peritoneal microbial environment was altered in patients with OC and that inclusion of selected peritoneal microbial features with current clinical features into prediction analyses will improve detection accuracy of patients with OC. Blood and peritoneal fluid were collected from consented patients that had sonography confirmed adnexal masses and were being seen at SIU School of Medicine Simmons Cancer Institute. Blood was processed and serum HE4 and CA-125 were measured. Peritoneal fluid was collected at the time of surgery and processed for Next Generation Sequencing (NGS) using 16S V4 exon bacterial primers and bioinformatics analyses. We found that patients with OC had a unique peritoneal microbial profile compared to patients with a benign mass. Using ensemble modeling and machine learning pathways, we identified 18 microbial features that were highly specific to OC pathology. Prediction analyses confirmed that inclusion of microbial features with serum tumor marker levels and control features (patient age and BMI) improved diagnostic accuracy compared to currently used models. We conclude that OC pathogenesis alters the peritoneal microbial environment and that these unique microbial features are important for accurate diagnosis of OC. Our study warrants further analyses of the importance of microbial features in regards to oncological diagnostics and possible prognostic and interventional medicine.
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Líquido Ascítico/microbiología , Antígeno Ca-125/sangre , Carcinoma Epitelial de Ovario/diagnóstico , Proteínas de la Membrana/sangre , Microbiota/genética , Neoplasias Ováricas/diagnóstico , Proteína 2 de Dominio del Núcleo de Cuatro Disulfuros WAP/análisis , Anciano , Carcinoma Epitelial de Ovario/sangre , Carcinoma Epitelial de Ovario/microbiología , Carcinoma Epitelial de Ovario/cirugía , Estudios Transversales , ADN Bacteriano/genética , ADN Bacteriano/aislamiento & purificación , Femenino , Humanos , Histerectomía , Laparoscopía , Aprendizaje Automático , Persona de Mediana Edad , Modelos Biológicos , Neoplasias Ováricas/sangre , Neoplasias Ováricas/microbiología , Neoplasias Ováricas/cirugía , Ovariectomía , Proyectos Piloto , Periodo Preoperatorio , Pronóstico , ARN Ribosómico 16S/genéticaRESUMEN
The hippocampus is involved in learning and memory and undergoes significant growth and maturation during the neonatal period. Environmental insults during this developmental timeframe can have lasting effects on brain structure and function. This study assessed hippocampal DNA methylation and gene transcription from two independent studies reporting reduced cognitive development stemming from early life environmental insults (iron deficiency and porcine reproductive and respiratory syndrome virus (PRRSv) infection) using porcine biomedical models. In total, 420 differentially expressed genes (DEGs) were identified between the reduced cognition and control groups, including genes involved in neurodevelopment and function. Gene ontology (GO) terms enriched for DEGs were associated with immune responses, angiogenesis, and cellular development. In addition, 116 differentially methylated regions (DMRs) were identified, which overlapped 125 genes. While no GO terms were enriched for genes overlapping DMRs, many of these genes are known to be involved in neurodevelopment and function, angiogenesis, and immunity. The observed altered methylation and expression of genes involved in neurological function suggest reduced cognition in response to early life environmental insults is due to altered cholinergic signaling and calcium regulation. Finally, two DMRs overlapped with two DEGs, VWF and LRRC32, which are associated with blood brain barrier permeability and regulatory T-cell activation, respectively. These results support the role of altered hippocampal DNA methylation and gene expression in early life environmentally-induced reductions in cognitive development across independent studies.
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Biomarcadores/análisis , Trastornos del Conocimiento/etiología , Metilación de ADN , Exposición a Riesgos Ambientales/efectos adversos , Epigénesis Genética , Hipocampo/patología , Animales , Animales Recién Nacidos , Diferenciación Celular , Trastornos del Conocimiento/metabolismo , Trastornos del Conocimiento/patología , Islas de CpG , Femenino , Hipocampo/metabolismo , PorcinosRESUMEN
Latent tuberculosis infection (LTBI) is estimated in nearly one quarter of the world's population, and of those immunocompetent and infected ~10% will proceed to active tuberculosis (TB). Current diagnostics cannot definitively identify LTBI and provide no insight into reactivation risk, thereby defining an unmet diagnostic challenge of incredible global significance. We introduce a new machine-learning-driven approach to LTBI diagnostics that leverages a high throughput, multiplexed cytokine detection technology and powerful bioinformatics to reveal multi-marker signatures for LTBI diagnosis and risk stratification. This approach is enabled through an individualized normalization procedure that allows disease-relevant biomarker signatures to be revealed despite heterogeneity in basal immune response. Specifically, cytokines secreted from antigen-challenged peripheral blood mononuclear cells were detected using silicon photonic sensor arrays and multidimensional data correlation of individually-normalized immune responses revealed signatures important for LTBI status. These results demonstrate a powerful combination of multiplexed biomarker detection technologies, precision immune normalization, and feature selection algorithms that revealed positively correlated multi-biomarker signatures for LTBI status and reactivation risk stratification from a relatively simple blood-based assay.
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Inmunoensayo/métodos , Tuberculosis Latente/diagnóstico , Leucocitos Mononucleares/microbiología , Aprendizaje Automático , Adulto , Anciano , Algoritmos , Antígenos/inmunología , Biomarcadores , Biología Computacional , Citocinas/inmunología , Pruebas Diagnósticas de Rutina , Femenino , Humanos , Sistema Inmunológico , Tuberculosis Latente/inmunología , Leucocitos Mononucleares/inmunología , Masculino , Tamizaje Masivo/métodos , Persona de Mediana Edad , Mycobacterium tuberculosis , Fotones , Estudios Prospectivos , Medición de Riesgo , Silicio , Prueba de Tuberculina , Flujo de TrabajoRESUMEN
In this study, we examined the relationships between anti-influenza virus serum antibody titers, clinical disease, and peripheral blood leukocyte (PBL) global gene expression during presymptomatic, acute, and convalescent illness in 83 participants infected with 2009 pandemic H1N1 virus in a human influenza challenge model. Using traditional statistical and logistic regression modeling approaches, profiles of differentially expressed genes that correlated with active viral shedding, predicted length of viral shedding, and predicted illness severity were identified. These analyses further demonstrated that challenge participants fell into three peripheral blood leukocyte gene expression phenotypes that significantly correlated with different clinical outcomes and prechallenge serum titers of antibodies specific for the viral neuraminidase, hemagglutinin head, and hemagglutinin stalk. Higher prechallenge serum antibody titers were inversely correlated with leukocyte responsiveness in participants with active disease and could mask expression of peripheral blood markers of clinical disease in some participants, including viral shedding and symptom severity. Consequently, preexisting anti-influenza antibodies may modulate PBL gene expression, and this must be taken into consideration in the development and interpretation of peripheral blood diagnostic and prognostic assays of influenza infection.IMPORTANCE Influenza A viruses are significant human pathogens that caused 83,000 deaths in the United States during 2017 to 2018, and there is need to understand the molecular correlates of illness and to identify prognostic markers of viral infection, symptom severity, and disease course. Preexisting antibodies against viral neuraminidase (NA) and hemagglutinin (HA) proteins play a critical role in lessening disease severity. We performed global gene expression profiling of peripheral blood leukocytes collected during acute and convalescent phases from a large cohort of people infected with A/H1N1pdm virus. Using statistical and machine-learning approaches, populations of genes were identified early in infection that correlated with active viral shedding, predicted length of shedding, or disease severity. Finally, these gene expression responses were differentially affected by increased levels of preexisting influenza antibodies, which could mask detection of these markers of contagiousness and disease severity in people with active clinical disease.
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Anticuerpos Antivirales/sangre , Glicoproteínas Hemaglutininas del Virus de la Influenza/inmunología , Gripe Humana/inmunología , Leucocitos/inmunología , Neuraminidasa/inmunología , Enfermedad Aguda , Adolescente , Adulto , Convalecencia , Protección Cruzada , Femenino , Perfilación de la Expresión Génica , Voluntarios Sanos , Pruebas de Inhibición de Hemaglutinación , Experimentación Humana , Humanos , Subtipo H1N1 del Virus de la Influenza A , Gripe Humana/sangre , Masculino , Persona de Mediana Edad , Esparcimiento de Virus , Adulto JovenRESUMEN
Conjugated estrogens (CE) and Bazedoxifene (BZA) combination is used to alleviate menopause-associated symptoms in women. CE+BZA undergo first-pass-metabolism in the liver and deconjugation by gut microbiome via ß-glucuronidase (GUS) enzyme inside the distal gut. To date, the impact of long-term exposure to CE+BZA on the gut microbiome or GUS activity has not been examined. Our study using an ovariectomized mouse model showed that CE+BZA administration did not affect the overall cecal or fecal microbiome community except that it decreased the abundance of Akkermansia, which was identified as a fecal biomarker correlated with weight gain. The fecal GUS activity was reduced significantly and was positively correlated with the abundance of Lactobacillaceae in the fecal microbiome. We further confirmed in Escherichia coli K12 and Lactobacillus gasseri ADH that Tamoxifen-, 4-hydroxy-Tamoxifen- and Estradiol-Glucuronides competed for GUS activity. Our study for the first time demonstrated that long-term estrogen supplementation directly modulated gut microbial GUS activity. Our findings implicate that long-term estrogen supplementation impacts composition of gut microbiota and microbial activity, which affects estrogen metabolism in the gut. Thus, it is possible to manipulate such activity to improve the efficacy and safety of long-term administered estrogens for postmenopausal women or breast cancer patients.
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Estrógenos Conjugados (USP)/farmacología , Heces/enzimología , Microbioma Gastrointestinal/efectos de los fármacos , Glucuronidasa/metabolismo , Indoles/farmacología , Animales , Biomarcadores/metabolismo , Interacciones Farmacológicas , Escherichia coli K12/efectos de los fármacos , Escherichia coli K12/fisiología , Heces/microbiología , Femenino , Lactobacillus gasseri/efectos de los fármacos , Lactobacillus gasseri/fisiología , Ratones , Ratones Endogámicos C57BL , Factores de TiempoRESUMEN
Homologous synteny blocks (HSBs) and evolutionary breakpoint regions (EBRs) in mammalian chromosomes are enriched for distinct DNA features, contributing to distinct phenotypes. To reveal HSB and EBR roles in avian evolution, we performed a sequence-based comparison of 21 avian and 5 outgroup species using recently sequenced genomes across the avian family tree and a newly-developed algorithm. We identified EBRs and HSBs in ancestral bird, archosaurian (bird, crocodile, and dinosaur), and reptile chromosomes. Genes involved in the regulation of gene expression and biosynthetic processes were preferably located in HSBs, including for example, avian-specific HSBs enriched for genes involved in limb development. Within birds, some lineage-specific EBRs rearranged genes were related to distinct phenotypes, such as forebrain development in parrots. Our findings provide novel evolutionary insights into genome evolution in birds, particularly on how chromosome rearrangements likely contributed to the formation of novel phenotypes.
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Evolución Molecular , Genoma/genética , Filogenia , Sintenía/genética , Caimanes y Cocodrilos/genética , Animales , Aves/genética , Mapeo Cromosómico , Cromosomas/genética , Reptiles/genética , Alineación de Secuencia , Análisis de Secuencia de ADN , Homología de SecuenciaRESUMEN
PURPOSE: Looping patterns rich in laminin are present in tissue samples of primary aggressive human uveal melanomas and their metastases. Because these extravascular patterns connect to blood vessels and transmit fluid in vitro and in vivo, the three-dimensional configuration of these patterns has been the subject of considerable speculation. In the current study, methods were devised to describe the three-dimensional configuration of looping extravascular matrix patterns in archival human uveal melanoma tissue. METHODS: Twenty-five serial 4-microm-thick sections from primary uveal melanoma tissue were labeled with fluorescence-tagged laminin and examined by confocal microscopy to generate a Z-series within each 4-microm-thick section. The z-series from each section was stacked using an immersive three-dimensional environment (ImmersaDesk; Fakespace, Kitchener, Ontario, Canada) to allow for precise alignment and compensation for distortion artifact. RESULTS: Extravascular matrix patterns that appeared to form loops in two dimensions were shown to represent thin wrappings around branching and twisting cylindrical groupings of melanoma cells. Blood vessels joined with some of these laminin-positive cylindrical wrappings. CONCLUSIONS: In this preliminary study, periodic acid-Schiff (PAS)-positive laminin-rich looping patterns in two-dimensional tissue sections appear to outline cylindrical branching packets of melanoma cells rather than spheroidal nests. The conduction of fluid through this extravascular system may provide a novel delivery system for contrast and diagnostic agents.
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Procesamiento de Imagen Asistido por Computador/métodos , Melanoma/irrigación sanguínea , Neovascularización Patológica/patología , Neoplasias de la Úvea/irrigación sanguínea , Antígenos CD34/metabolismo , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , Imagenología Tridimensional/métodos , Laminina/metabolismo , Microscopía Confocal , Microscopía FluorescenteRESUMEN
The Tibetan antelope (Pantholops hodgsonii) is endemic to the extremely inhospitable high-altitude environment of the Qinghai-Tibetan Plateau, a region that has a low partial pressure of oxygen and high ultraviolet radiation. Here we generate a draft genome of this artiodactyl and use it to detect the potential genetic bases of highland adaptation. Compared with other plain-dwelling mammals, the genome of the Tibetan antelope shows signals of adaptive evolution and gene-family expansion in genes associated with energy metabolism and oxygen transmission. Both the highland American pika, and the Tibetan antelope have signals of positive selection for genes involved in DNA repair and the production of ATPase. Genes associated with hypoxia seem to have experienced convergent evolution. Thus, our study suggests that common genetic mechanisms might have been utilized to enable high-altitude adaptation.
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Antílopes/genética , Genoma/genética , Adaptación Fisiológica/genética , Altitud , Animales , Secuencia de Bases , Evolución Molecular , Ontología de Genes , Heterocigoto , Datos de Secuencia Molecular , Familia de Multigenes/genética , Polimorfismo de Nucleótido Simple/genética , Selección Genética , Análisis de Secuencia de ADN , Tibet , Ursidae/genéticaRESUMEN
Domestic yaks (Bos grunniens) provide meat and other necessities for Tibetans living at high altitude on the Qinghai-Tibetan Plateau and in adjacent regions. Comparison between yak and the closely related low-altitude cattle (Bos taurus) is informative in studying animal adaptation to high altitude. Here, we present the draft genome sequence of a female domestic yak generated using Illumina-based technology at 65-fold coverage. Genomic comparisons between yak and cattle identify an expansion in yak of gene families related to sensory perception and energy metabolism, as well as an enrichment of protein domains involved in sensing the extracellular environment and hypoxic stress. Positively selected and rapidly evolving genes in the yak lineage are also found to be significantly enriched in functional categories and pathways related to hypoxia and nutrition metabolism. These findings may have important implications for understanding adaptation to high altitude in other animal species and for hypoxia-related diseases in humans.
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Aclimatación/genética , Altitud , Bovinos/genética , Bovinos/fisiología , Animales , Secuencia de Bases , ADN/genética , Evolución Molecular , Femenino , Genoma , Datos de Secuencia Molecular , Familia de Multigenes , Filogenia , Selección Genética , Especificidad de la EspecieRESUMEN
The persistence of large blocks of homologous synteny and a high frequency of breakpoint reuse are distinctive features of mammalian chromosomes that are not well understood in evolutionary terms. To gain a better understanding of the evolutionary forces that affect genome architecture, synteny relationships among 10 amniotes (human, chimp, macaque, rat, mouse, pig, cattle, dog, opossum, and chicken) were compared at <1 human-Mbp resolution. Homologous synteny blocks (HSBs; N = 2233) and chromosome evolutionary breakpoint regions (EBRs; N = 1064) were identified from pairwise comparisons of all genomes. Analysis of the size distribution of HSBs shared in all 10 species' chromosomes (msHSBs) identified three (>20 Mbp) that are larger than expected by chance. Gene network analysis of msHSBs >3 human-Mbp and EBRs <1 Mbp demonstrated that msHSBs are significantly enriched for genes involved in development of the central nervous and other organ systems, whereas EBRs are enriched for genes associated with adaptive functions. In addition, we found EBRs are significantly enriched for structural variations (segmental duplications, copy number variants, and indels), retrotransposed and zinc finger genes, and single nucleotide polymorphisms. These results demonstrate that chromosome breakage in evolution is nonrandom and that HSBs and EBRs are evolving in distinctly different ways. We suggest that natural selection acts on the genome to maintain combinations of genes and their regulatory elements that are essential to fundamental processes of amniote development and biological organization. Furthermore, EBRs may be used extensively to generate new genetic variation and novel combinations of genes and regulatory elements that contribute to adaptive phenotypes.
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Rotura Cromosómica , Cromosomas de los Mamíferos/genética , Evolución Molecular , Sintenía/genética , Animales , Duplicación de Gen , Genoma , Humanos , Modelos Genéticos , Selección GenéticaRESUMEN
The genome organizations of eight phylogenetically distinct species from five mammalian orders were compared in order to address fundamental questions relating to mammalian chromosomal evolution. Rates of chromosome evolution within mammalian orders were found to increase since the Cretaceous-Tertiary boundary. Nearly 20% of chromosome breakpoint regions were reused during mammalian evolution; these reuse sites are also enriched for centromeres. Analysis of gene content in and around evolutionary breakpoint regions revealed increased gene density relative to the genome-wide average. We found that segmental duplications populate the majority of primate-specific breakpoints and often flank inverted chromosome segments, implicating their role in chromosomal rearrangement.