Most great ape genetic variation remains uncharacterized; however,\ud its study is critical for understanding population history, recombination,\ud selection and susceptibility to disease.Herewe sequence\ud to high coverage a total of 79 wild- and captive-born individuals\ud representing all six great ape species and seven subspecies and report\ud 88.8 million single nucleotide polymorphisms. Our analysis provides\ud support for genetically distinct populations within each species,\ud signals of gene flow, and the split of common chimpanzees\ud into two distinct groups: Nigeria–Cameroon/western and central/\ud eastern populations.We find extensive inbreeding in almost all wild\ud populations, with eastern gorillas being the most extreme. Inferred\ud effective population sizes have varied radically over timein different\ud lineages and this appears to have a profound effect on the genetic\ud diversity at, or close to, genes in almost all species. We discover and\ud assign 1,982 loss-of-function variants throughout the human and\ud great ape lineages, determining that the rate of gene loss has not\ud been different in the human branch compared to other internal\ud branches in the great ape phylogeny. This comprehensive catalogue\ud of great ape genomediversity provides a framework for understanding\ud evolution and a resource for more effective management of wild\ud and captive great ape populations
Gibbons are small arboreal apes that display an accelerated rate of evolutionary chromosomal rearrangement and occupy a key node in the primate phylogeny between Old World monkeys and great apes. Here we present the assembly and analysis of a northern white-cheeked gibbon (Nomascus leucogenys) genome. We describe the propensity for a gibbon-specific retrotransposon (LAVA) to insert into chromosome segregation genes and alter transcription by providing a premature termination site, suggesting a possible molecular mechanism for the genome plasticity of the gibbon lineage. We further show that the gibbon genera (Nomascus, Hylobates, Hoolock and Symphalangus) experienced a near-instantaneous radiation ~5 million years ago, coincident with major geographical changes in Southeast Asia that caused cycles of habitat compression and expansion. Finally, we identify signatures of positive selection in genes important for forelimb development (TBX5) and connective tissues (COL1A1) that may have been involved in the adaptation of gibbons to their arboreal habitat.
Summary Purpose The management of epilepsy in children is particularly challenging when seizures are resistant to anti-epileptic medications, or undergo many changes in seizure type over time, or have comorbid cognitive, behavioral, or motor deficits. Despite efforts to classify such epilepsies based on clinical and electroencephalographic criteria, many children never receive a definitive etiological diagnosis. Whole exome sequencing (WES) is proving to be a highly effective method for identifying de novo variants that cause neurological disorders, especially those associated with abnormal brain development. Here we explore the utility of WES for identifying candidate causal de novo variants in a cohort of children with heterogeneous sporadic epilepsies without etiological diagnoses. Methods We performed WES (mean coverage ~40X) on 10 trios comprised of unaffected parents and a child with sporadic epilepsy characterized by difficult-to-control seizures and some combination of developmental delay, epileptic encephalopathy, autistic features, cognitive impairment, or motor deficits. Sequence processing and variant calling were performed using standard bioinformatics tools. A custom filtering system was used to prioritize de novo variants of possible functional significance for validation by Sanger sequencing. Key Findings In nine of ten probands, we identified one or more de novo variants predicted to alter protein function, for a total of 15. Four probands had de novo mutations in genes previously shown to harbor heterozygous mutations in patients with severe, early-onset epilepsies (two in SCN1A, and one each in CDKL5 and EEF1A2). In three children, the de novo variants were in genes with functional roles that are plausibly relevant to epilepsy (KCNH5, CLCN4 and ARHGEF15). The variant in KCNH5 alters one of the highly conserved arginine residues of the voltage sensor of the encoded voltage-gated potassium channel. In vitro analyses using cell-based assays revealed that the CLCN4 mutation greatly impaired ion transport by the ClC-4 2Cl−/H+-exchanger and that the mutation in ARHGEF15 reduced GEF exchange activity of the gene product, Ephexin5, by about 50%. Interestingly, these seven probands all presented with seizures within the first six months of life, and six of these have intractable seizures. Significance The finding that seven of ten children carried de novo mutations in genes of known or plausible clinical significance to neuronal excitability suggests that WES will be of use for the molecular genetic diagnosis of sporadic epilepsies in children, especially when seizures are of early onset and difficult to control.
The unique inheritance pattern of the X chromosome exposes it to natural selection in a way that is different from that of the autosomes, potentially resulting in accelerated evolution. We perform a comparative analysis of X chromosome polymorphism in 10 great ape species, including humans. In most species, we identify striking megabase-wide regions, where nucleotide diversity is less than 20% of the chromosomal average. Such regions are found exclusively on the X chromosome. The regions overlap partially among species, suggesting that the underlying targets are partly shared among species. The regions have higher proportions of singleton SNPs, higher levels of population differentiation, and a higher nonsynonymous-to-synonymous substitution ratio than the rest of the X chromosome. We show that the extent to which diversity is reduced is incompatible with direct selection or the action of background selection and soft selective sweeps alone, and therefore, we suggest that very strong selective sweeps have independently targeted these specific regions in several species. The only genomic feature that we can identify as strongly associated with loss of diversity is the location of testis-expressed ampliconic genes, which also have reduced diversity around them. We hypothesize that these genes may be responsible for selective sweeps in the form of meiotic drive caused by an intragenomic conflict in male meiosis. X-chromosome evolution | great apes | selective sweeps | ampliconic genes | meiotic drive
There is an urgent need to identify cellular/molecular mechanisms responsible for severe COVID-19 progressing to mortality. We initially performed untargeted/targeted lipidomics and focused biochemistry on 127 plasma samples and found elevated metabolites associated with secreted phospholipase A2 (sPLA2) activity and mitochondrial dysfunction in severe COVID-19 patients.Deceased COVID-19 patients had higher levels of circulating, catalytically active sPLA2 Group IIA (sPLA2-IIA), with a median value 9.6-fold higher than mild patients and 5.0-fold higher than severe COVID-19 survivors. Elevated sPLA2-IIA levels paralleled several indices of COVID-19 disease severity (e.g., kidney dysfunction, hypoxia, multiple organ dysfunction). A decision tree generated by machine learning identified sPLA2-IIA levels as a central node in stratifying patients that succumbed to COVID-19. Random forest analysis and LASSO-based regression analysis additionally identified sPLA2-IIA and blood urea nitrogen (BUN) as the key variables among 80 clinical indices in predicting COVID-19 mortality. The combined PLA-BUN index performed significantly better than either alone. An independent cohort (n=154) confirmed higher plasma sPLA2-IIA levels in deceased patients vs. severe or mild COVID-19, with the PLA-BUN indexbased decision tree satisfactorily stratifying mild, severe, and deceased COVID-19 patients. With clinically tested inhibitors available, this study supports sPLA2-IIA as a therapeutic target to reduce COVID-19 mortality.
Genome-wide single nucleotide polymorphism (SNP) data are now quickly and inexpensively acquired, raising the prospect of creating personalized dietary recommendations based on an individual’s genetic variability at multiple SNPs. However, relatively little is known about most specific gene–diet interactions, and many molecular and clinical phenotypes of interest (e.g., body mass index [BMI]) involve multiple genes. In this review, we discuss direct to consumer genetic testing (DTC-GT) and the current potential for precision nutrition based on an individual’s genetic data. We review important issues such as dietary exposure and genetic architecture addressing the concepts of penetrance, pleiotropy, epistasis, polygenicity, and epigenetics. More specifically, we discuss how they complicate using genotypic data to predict phenotypes as well as response to dietary interventions. Then, several examples (including caffeine sensitivity, alcohol dependence, non-alcoholic fatty liver disease, obesity/appetite, cardiovascular, Alzheimer’s disease, folate metabolism, long-chain fatty acid biosynthesis, and vitamin D metabolism) are provided illustrating how genotypic information could be used to inform nutritional recommendations. We conclude by examining ethical considerations and practical applications for using genetic information to inform dietary choices and the future role genetics may play in adopting changes beyond population-wide healthy eating guidelines.
Gibbons are believed to have diverged from the larger great apes 16.8 MYA and today reside in the rainforests of Southeast Asia. Based on their diploid chromosome number, the family Hylobatidae is divided into four genera, Nomascus, Symphalangus, Hoolock, and Hylobates. Genetic studies attempting to elucidate the phylogenetic relationships among gibbons using karyotypes, mitochondrial DNA (mtDNA), the Y chromosome, and short autosomal sequences have been inconclusive . To examine the relationships among gibbon genera in more depth, we performed second-generation whole genome sequencing (WGS) to a mean of 153 coverage in two individuals from each genus. We developed a coalescent-based approximate Bayesian computation (ABC) method incorporating a model of sequencing error generated by high coverage exome validation to infer the branching order, divergence times, and effective population sizes of gibbon taxa. Although Hoolock and Symphalangus are likely sister taxa, we could not confidently resolve a single bifurcating tree despite the large amount of data analyzed. Instead, our results support the hypothesis that all four gibbon genera diverged at approximately the same time. Assuming an autosomal mutation rate of 1 3 10 29 /site/year this speciation process occurred 5 MYA during a period in the Early Pliocene characterized by climatic shifts and fragmentation of the Sunda shelf forests. Whole genome sequencing of additional individuals will be vital for inferring the extent of gene flow among species after the separation of the gibbon genera.KEYWORDS approximate Bayesian computation; gibbon species; rapid radiation; whole genome sequences T HE family Hylobatidae, commonly known as gibbons, is believed to have diverged from the larger great apes 16.8 MYA . Sometimes known as small apes, gibbons demonstrate substantial morphological differentiation from the great apes; their much smaller bodies are highly adapted to an arboreal mode of locomotion in the rainforests of Southeast Asia. They also demonstrate very little sexual dimorphism that may, in part, be related to their generally monogamous mating patterns (Fuentes 2000) (although some gibbon species develop differences in coat color at sexual maturity).Each species demonstrates distinct "call" and "song" types (Geissmann 2002); however, attempts to classify gibbon species and genera based solely on morphological features have been problematic (Mootnick 2006). Primarily on the basis of their karyotypes, gibbons are now divided into four major genera, with Nomascus, Symphalangus, Hylobates, and Hoolock each possessing 52, 50, 44, and 38 diploid chromosomes, respectively. While many genetic studies have been performed, including a number based on karyotypes (Müller et al. 2003), mitochondrial DNA (mtDNA) (Hayashi et al. 1995;Takacs et al. 2005;Monda et al. 2007;Whittaker et al. 2007;Matsudaira and Ishida 2010;Van Ngoc et al. 2010), Y chromosomes (Chan et al. 2012), Arthrobacter luteus (ALU) repeats (Meyer et al. 2012), and short stretches of autosomal seq...
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