Publications by authors named "Joshua Schraiber"

Article Synopsis
  • - The study presents a comprehensive whole-genome dataset of 34 Armenian individuals, revealing their population structure and demographic history, showing that eastern, central, and western Armenians are genetically similar.
  • - The Sasun population, previously thought to have been heavily influenced by Assyrian genetics, was found to have a unique genetic profile resulting from a recent bottleneck event rather than direct Assyrian ancestry.
  • - Research also explores the origins of Armenians, finding no support for Herodotus’ claims of Balkan ancestry, but identifying connections to ancient Neolithic Levantine Farmers and documenting unique mutations related to common health disorders in the community.
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Many phenotypic traits have a polygenic genetic basis, making it challenging to learn their genetic architectures and predict individual phenotypes. One promising avenue to resolve the genetic basis of complex traits is through evolve-and-resequence (E&R) experiments, in which laboratory populations are exposed to some selective pressure and trait-contributing loci are identified by extreme frequency changes over the course of the experiment. However, small laboratory populations will experience substantial random genetic drift, and it is difficult to determine whether selection played a role in a given allele frequency change (AFC).

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Article Synopsis
  • The goal in both statistical genetics and phylogenetics is to uncover relationships between genetic factors and traits, but their statistical methods differ significantly.
  • The increasing overlap in research areas like medicine and biology necessitates a unified approach, as traditional boundaries between these two fields become less clear.
  • By introducing a general covariance model, the authors illustrate that existing methods can be harmonized, allowing for shared techniques to improve research accuracy and mitigate misleading correlations in both genetics and evolutionary studies.
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As genetic sequencing costs have plummeted, datasets with sizes previously un-thinkable have begun to appear. Such datasets present new opportunities to learn about evolutionary history, particularly via rare alleles that record the very recent past. However, beyond the computational challenges inherent in the analysis of many large-scale datasets, large population-genetic datasets present theoretical problems.

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Many remarkable innovations have repeatedly occurred across vast evolutionary distances. When convergent traits emerge on the tree of life, they are sometimes driven by the same underlying gene families, while other times many different gene families are involved. Conversely, a gene family may be repeatedly recruited for a single trait or many different traits.

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Many phenotypic traits have a polygenic genetic basis, making it challenging to learn their genetic architectures and predict individual phenotypes. One promising avenue to resolve the genetic basis of complex traits is through evolve-and-resequence experiments, in which laboratory populations are exposed to some selective pressure and trait-contributing loci are identified by extreme frequency changes over the course of the experiment. However, small laboratory populations will experience substantial random genetic drift, and it is difficult to determine whether selection played a roll in a given allele frequency change.

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In both statistical genetics and phylogenetics, a major goal is to identify correlations between genetic loci or other aspects of the phenotype or environment and a focal trait. In these two fields, there are sophisticated but disparate statistical traditions aimed at these tasks. The disconnect between their respective approaches is becoming untenable as questions in medicine, conservation biology, and evolutionary biology increasingly rely on integrating data from within and among species, and once-clear conceptual divisions are becoming increasingly blurred.

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Collecting genomics data across multiple heterogeneous populations (e.g., across different cancer types) has the potential to improve our understanding of disease.

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Article Synopsis
  • It’s challenging to distinguish whether phenotypic differences between groups arise from genetic or environmental factors without controlled experiments.
  • Some researchers argue this issue mainly arises in extreme cases and propose methods that relate heritable variation within groups to that among groups.
  • The authors review three approaches—between-group heritability, a specific statistic from evolutionary genetics, and ancestry variation methods—demonstrating mathematically that within-group data cannot adequately separate the genetic and environmental causes of differences between groups, supporting their argument with simulation results.
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Understanding the genetic basis of complex phenotypes is a central pursuit of genetics. Genome-wide association studies (GWASs) are a powerful way to find genetic loci associated with phenotypes. GWASs are widely and successfully used, but they face challenges related to the fact that variants are tested for association with a phenotype independently, whereas in reality variants at different sites are correlated because of their shared evolutionary history.

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  • Noncoding DNA helps scientists understand how genes work and how they relate to diseases in humans.
  • Researchers studied the DNA of many primates to find specific regulatory parts that are important for gene regulation.
  • They discovered a lot of these regulatory elements in humans that are different from those in other mammals, which can help explain human traits and health issues.
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Without the ability to control or randomize environments (or genotypes), it is difficult to determine the degree to which observed phenotypic differences between two groups of individuals are due to genetic vs. environmental differences. However, some have suggested that these concerns may be limited to pathological cases, and methods have appeared that seem to give-directly or indirectly-some support to claims that aggregate heritable variation within groups can be related to heritable variation among groups.

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The rich diversity of morphology and behavior displayed across primate species provides an informative context in which to study the impact of genomic diversity on fundamental biological processes. Analysis of that diversity provides insight into long-standing questions in evolutionary and conservation biology and is urgent given severe threats these species are facing. Here, we present high-coverage whole-genome data from 233 primate species representing 86% of genera and all 16 families.

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Personalized genome sequencing has revealed millions of genetic differences between individuals, but our understanding of their clinical relevance remains largely incomplete. To systematically decipher the effects of human genetic variants, we obtained whole-genome sequencing data for 809 individuals from 233 primate species and identified 4.3 million common protein-altering variants with orthologs in humans.

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Article Synopsis
  • * Individuals with extreme traits or high risk for serious diseases are more effectively identified through a small number of rare variants rather than through numerous common variants that have minimal effects.
  • * By integrating rare variants from related genes into a single genetic risk model, we created a more effective tool for predicting disease risk across different populations, outperforming traditional methods based on common variants.
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  • * Rare mutations in certain genes have a much stronger impact on severe diseases than more common genetic variations.
  • * By using rare variants to create a genetic risk model, we were able to predict disease risk more effectively across different populations compared to traditional methods that rely on common variants.
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Unlabelled: Personalized genome sequencing has revealed millions of genetic differences between individuals, but our understanding of their clinical relevance remains largely incomplete. To systematically decipher the effects of human genetic variants, we obtained whole genome sequencing data for 809 individuals from 233 primate species, and identified 4.3 million common protein-altering variants with orthologs in human.

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Understanding the genetic basis of complex phenotypes is a central pursuit of genetics. Genome-wide Association Studies (GWAS) are a powerful way to find genetic loci associated with phenotypes. GWAS are widely and successfully used, but they face challenges related to the fact that variants are tested for association with a phenotype independently, whereas in reality variants at different sites are correlated because of their shared evolutionary history.

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Sweat bees have repeatedly gained and lost eusociality, a transition from individual to group reproduction. Here we generate chromosome-length genome assemblies for 17 species and identify genomic signatures of evolutionary trade-offs associated with transitions between social and solitary living. Both young genes and regulatory regions show enrichment for these molecular patterns.

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Human populations have been shaped by catastrophes that may have left long-lasting signatures in their genomes. One notable example is the second plague pandemic that entered Europe in ca. 1,347 CE and repeatedly returned for over 300 years, with typical village and town mortality estimated at 10%-40%.

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The genetic architecture of atrial fibrillation (AF) encompasses low impact, common genetic variants and high impact, rare variants. Here, we characterize a high impact AF-susceptibility allele, KCNQ1 R231H, and describe its transcontinental geographic distribution and history. Induced pluripotent stem cell-derived cardiomyocytes procured from risk allele carriers exhibit abbreviated action potential duration, consistent with a gain-of-function effect.

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Background: We present ARCHes, a fast and accurate haplotype-based approach for inferring an individual's ancestry composition. Our approach works by modeling haplotype diversity from a large, admixed cohort of hundreds of thousands, then annotating those models with population information from reference panels of known ancestry.

Results: The running time of ARCHes does not depend on the size of a reference panel because training and testing are separate processes, and the inferred population-annotated haplotype models can be written to disk and reused to label large test sets in parallel (in our experiments, it averages less than one minute to assign ancestry from 32 populations using 10 CPU).

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Neanderthals and anatomically modern humans overlapped geographically for a period of over 30,000 years following human migration out of Africa. During this period, Neanderthals and humans interbred, as evidenced by Neanderthal portions of the genome carried by non-African individuals today. A key observation is that the proportion of Neanderthal ancestry is ~12-20% higher in East Asian individuals relative to European individuals.

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Article Synopsis
  • The study focused on genetic diversity in California voles by examining introgression between two closely related lineages in a contact zone, testing whether nuclear gene flow is greater than mitochondrial gene flow.
  • Findings showed that the two lineages diverged relatively recently (8.5-54k years ago), and there was no evidence of hybrid individuals or consistent gene flow at the contact zone, with mitochondrial markers indicating past hybridization.
  • The research highlights contrasting patterns of introgression between mitochondrial and nuclear markers, prompting further investigation into isolating mechanisms like habitat use and mate choice to understand genetic boundaries better.
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We present a multispecies coalescent model for quantitative traits that allows for evolutionary inferences at micro- and macroevolutionary scales. A major advantage of this model is its ability to incorporate genealogical discordance underlying a quantitative trait. We show that discordance causes a decrease in the expected trait covariance between more closely related species relative to more distantly related species.

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