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Harris M, Kim BY, Garud N. Enrichment of hard sweeps on the X chromosome compared to autosomes in six Drosophila species. Genetics 2024; 226:iyae019. [PMID: 38366786 PMCID: PMC10990427 DOI: 10.1093/genetics/iyae019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/17/2024] [Accepted: 01/18/2024] [Indexed: 02/18/2024] Open
Abstract
The X chromosome, being hemizygous in males, is exposed one-third of the time increasing the visibility of new mutations to natural selection, potentially leading to different evolutionary dynamics than autosomes. Recently, we found an enrichment of hard selective sweeps over soft selective sweeps on the X chromosome relative to the autosomes in a North American population of Drosophila melanogaster. To understand whether this enrichment is a universal feature of evolution on the X chromosome, we analyze diversity patterns across 6 commonly studied Drosophila species. We find an increased proportion of regions with steep reductions in diversity and elevated homozygosity on the X chromosome compared to autosomes. To assess if these signatures are consistent with positive selection, we simulate a wide variety of evolutionary scenarios spanning variations in demography, mutation rate, recombination rate, background selection, hard sweeps, and soft sweeps and find that the diversity patterns observed on the X are most consistent with hard sweeps. Our findings highlight the importance of sex chromosomes in driving evolutionary processes and suggest that hard sweeps have played a significant role in shaping diversity patterns on the X chromosome across multiple Drosophila species.
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Affiliation(s)
- Mariana Harris
- Department of Computational Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Bernard Y Kim
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Nandita Garud
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Human Genetics, University of California Los Angeles, Los Angeles, CA 90095, USA
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Harris M, Kim B, Garud N. Enrichment of hard sweeps on the X chromosome compared to autosomes in six Drosophila species. bioRxiv 2023:2023.06.21.545888. [PMID: 38106201 PMCID: PMC10723260 DOI: 10.1101/2023.06.21.545888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
The X chromosome, being hemizygous in males, is exposed one third of the time increasing the visibility of new mutations to natural selection, potentially leading to different evolutionary dynamics than autosomes. Recently, we found an enrichment of hard selective sweeps over soft selective sweeps on the X chromosome relative to the autosomes in a North American population of Drosophila melanogaster. To understand whether this enrichment is a universal feature of evolution on the X chromosome, we analyze diversity patterns across six commonly studied Drosophila species. We find an increased proportion of regions with steep reductions in diversity and elevated homozygosity on the X chromosome compared to autosomes. To assess if these signatures are consistent with positive selection, we simulate a wide variety of evolutionary scenarios spanning variations in demography, mutation rate, recombination rate, background selection, hard sweeps, and soft sweeps, and find that the diversity patterns observed on the X are most consistent with hard sweeps. Our findings highlight the importance of sex chromosomes in driving evolutionary processes and suggest that hard sweeps have played a significant role in shaping diversity patterns on the X chromosome across multiple Drosophila species.
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Affiliation(s)
- Mariana Harris
- Department of Computational Medicine, University of California Los Angeles, Los Angeles California, United States of America
| | - Bernard Kim
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Nandita Garud
- Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles California, United States of America
- Department of Human Genetics, University of California, Los Angeles, California, United States of America
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Mah JC, Lohmueller KE, Garud N. Inference of the demographic histories and selective effects of human gut commensal microbiota over the course of human history. bioRxiv 2023:2023.11.09.566454. [PMID: 38014007 PMCID: PMC10680615 DOI: 10.1101/2023.11.09.566454] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Despite the importance of gut commensal microbiota to human health, there is little knowledge about their evolutionary histories, including their population demographic histories and their distributions of fitness effects (DFE) of new mutations. Here, we infer the demographic histories and DFEs of 27 of the most highly prevalent and abundant commensal gut microbial species in North Americans over timescales exceeding human generations using a collection of lineages inferred from a panel of healthy hosts. We find overall reductions in genetic variation among commensal gut microbes sampled from a Western population relative to an African rural population. Additionally, some species in North American microbiomes display contractions in population size and others expansions, potentially occurring at several key historical moments in human history. DFEs across species vary from highly to mildly deleterious, with accessory genes experiencing more drift compared to core genes. Within genera, DFEs tend to be more congruent, reflective of underlying phylogenetic relationships. Taken together, these findings suggest that human commensal gut microbes have distinct evolutionary histories, possibly reflecting the unique roles of individual members of the microbiome.
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Mourya H, Garud N, Joshi R, Akram W, Singh N. Formulation and Optimization of Propranolol Bilayer Tablets: A Potential Approach for Effective Management of Hypertension. Indian J Pharm Sci 2023. [DOI: 10.36468/pharmaceutical-sciences.1081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023] Open
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Abstract
The evolutionary dynamics of gut microbiota are still being explored. In this issue of Cell Host & Microbe, Dapa et al. conduct an experimental evolution study in mice to track the rapid adaptation of the gut microbiome based on host diet.
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Affiliation(s)
- Nandita Garud
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA, USA; Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA, USA.
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Harpak A, Garud N, Rosenberg NA, Petrov DA, Combs M, Pennings PS, Munshi-South J. Genetic Adaptation in New York City Rats. Genome Biol Evol 2020; 13:5991490. [PMID: 33211096 PMCID: PMC7851592 DOI: 10.1093/gbe/evaa247] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2020] [Indexed: 02/06/2023] Open
Abstract
Brown rats (Rattus norvegicus) thrive in urban environments by navigating the anthropocentric environment and taking advantage of human resources and by-products. From the human perspective, rats are a chronic problem that causes billions of dollars in damage to agriculture, health, and infrastructure. Did genetic adaptation play a role in the spread of rats in cities? To approach this question, we collected whole-genome sequences from 29 brown rats from New York City (NYC) and scanned for genetic signatures of adaptation. We tested for 1) high-frequency, extended haplotypes that could indicate selective sweeps and 2) loci of extreme genetic differentiation between the NYC sample and a sample from the presumed ancestral range of brown rats in northeast China. We found candidate selective sweeps near or inside genes associated with metabolism, diet, the nervous system, and locomotory behavior. Patterns of differentiation between NYC and Chinese rats at putative sweep loci suggest that many sweeps began after the split from the ancestral population. Together, our results suggest several hypotheses on adaptation in rats living in proximity to humans.
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Affiliation(s)
- Arbel Harpak
- Department of Biological Sciences, Columbia University
| | - Nandita Garud
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles
| | | | | | - Matthew Combs
- Department of Biological Sciences, Fordham University.,Department of Ecology, Evolution and Environmental Biology, Columbia University
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Nayfach S, Rodriguez-Mueller B, Garud N, Pollard KS. An integrated metagenomics pipeline for strain profiling reveals novel patterns of bacterial transmission and biogeography. Genome Res 2016; 26:1612-1625. [PMID: 27803195 PMCID: PMC5088602 DOI: 10.1101/gr.201863.115] [Citation(s) in RCA: 285] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 09/08/2016] [Indexed: 01/19/2023]
Abstract
We present the Metagenomic Intra-species Diversity Analysis System (MIDAS), which is an integrated computational pipeline for quantifying bacterial species abundance and strain-level genomic variation, including gene content and single-nucleotide polymorphisms (SNPs), from shotgun metagenomes. Our method leverages a database of more than 30,000 bacterial reference genomes that we clustered into species groups. These cover the majority of abundant species in the human microbiome but only a small proportion of microbes in other environments, including soil and seawater. We applied MIDAS to stool metagenomes from 98 Swedish mothers and their infants over one year and used rare SNPs to track strains between hosts. Using this approach, we found that although species compositions of mothers and infants converged over time, strain-level similarity diverged. Specifically, early colonizing bacteria were often transmitted from an infant’s mother, while late colonizing bacteria were often transmitted from other sources in the environment and were enriched for spore-formation genes. We also applied MIDAS to 198 globally distributed marine metagenomes and used gene content to show that many prevalent bacterial species have population structure that correlates with geographic location. Strain-level genetic variants present in metagenomes clearly reveal extensive structure and dynamics that are obscured when data are analyzed at a coarser taxonomic resolution.
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Affiliation(s)
- Stephen Nayfach
- Integrative Program in Quantitative Biology, University of California, San Francisco, San Francisco, California 94158, USA.,Gladstone Institutes, San Francisco, California 94158, USA
| | | | - Nandita Garud
- Gladstone Institutes, San Francisco, California 94158, USA
| | - Katherine S Pollard
- Integrative Program in Quantitative Biology, University of California, San Francisco, San Francisco, California 94158, USA.,Gladstone Institutes, San Francisco, California 94158, USA.,Institute for Human Genetics, Institute for Computational Health Sciences, and Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California 94158, USA
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Garud N, Garud A. Preparation and In-vitro Evaluation of Metformin Microspheres Using Non-Aqueous Solvent Evaporation Technique. TROP J PHARM RES 2012. [DOI: 10.4314/tjpr.v11i4.8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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