1
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López-Cortegano E, Chebib J, Jonas A, Vock A, Künzel S, Tautz D, Keightley PD. Variation in the Spectrum of New Mutations among Inbred Strains of Mice. Mol Biol Evol 2024; 41:msae163. [PMID: 39101589 PMCID: PMC11327921 DOI: 10.1093/molbev/msae163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 07/06/2024] [Accepted: 07/31/2024] [Indexed: 08/06/2024] Open
Abstract
The mouse serves as a mammalian model for understanding the nature of variation from new mutations, a question that has both evolutionary and medical significance. Previous studies suggest that the rate of single-nucleotide mutations (SNMs) in mice is ∼50% of that in humans. However, information largely comes from studies involving the C57BL/6 strain, and there is little information from other mouse strains. Here, we study the mutations that accumulated in 59 mouse lines derived from four inbred strains that are commonly used in genetics and clinical research (BALB/cAnNRj, C57BL/6JRj, C3H/HeNRj, and FVB/NRj), maintained for eight to nine generations by brother-sister mating. By analyzing Illumina whole-genome sequencing data, we estimate that the average rate of new SNMs in mice is ∼μ = 6.7 × 10-9. However, there is substantial variation in the spectrum of SNMs among strains, so the burden from new mutations also varies among strains. For example, the FVB strain has a spectrum that is markedly skewed toward C→A transversions and is likely to experience a higher deleterious load than other strains, due to an increased frequency of nonsense mutations in glutamic acid codons. Finally, we observe substantial variation in the rate of new SNMs among DNA sequence contexts, CpG sites, and their adjacent nucleotides playing an important role.
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Affiliation(s)
| | - Jobran Chebib
- Institute of Ecology and Evolution, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Anika Jonas
- Department for Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany
| | - Anastasia Vock
- Department for Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany
| | - Sven Künzel
- Department for Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany
| | - Diethard Tautz
- Department for Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany
| | - Peter D Keightley
- Institute of Ecology and Evolution, University of Edinburgh, Edinburgh, EH9 3FL, UK
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2
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Jakkamsetti V, Ma Q, Angulo G, Scudder W, Beutler B, Pascual JM. Genetic influences on motor learning and performance and superperforming mutants revealed by random mutational survey of the mouse genome. J Physiol 2024; 602:2649-2664. [PMID: 38299894 PMCID: PMC11142877 DOI: 10.1113/jp285505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 01/09/2024] [Indexed: 02/02/2024] Open
Abstract
Evolution depends upon genetic variations that influence physiology. As defined in a genetic screen, phenotypic performance may be enhanced or degraded by such mutations. We set out to detect mutations that influence motor function, including motor learning. Thus, we tested the motor effects of 36,444 non-synonymous coding/splicing mutations induced in the germline of C57BL/6J mice with N-ethyl-N-nitrosourea by measuring changes in the performance of repetitive rotarod trials while blinded to genotype. Automated meiotic mapping was used to implicate individual mutations in causation. In total, 32,726 mice bearing all the variant alleles were screened. This was complemented with the simultaneous testing of 1408 normal mice for reference. In total, 16.3% of autosomal genes were thus rendered detectably hypomorphic or nullified by mutations in homozygosity and motor tested in at least three mice. This approach allowed us to identify superperformance mutations in Rif1, Tk1, Fan1 and Mn1. These genes are primarily related, among other less well-characterized functions, to nucleic acid biology. We also associated distinct motor learning patterns with groups of functionally related genes. These functional sets included, preferentially, histone H3 methyltransferase activity for mice that learnt at an accelerated rate relative to the remaining mutant mice. The results allow for an estimation of the fraction of mutations that can modify a behaviour influential for evolution such as locomotion. They may also enable, once the loci are further validated and the mechanisms elucidated, the harnessing of the activity of the newly identified genes to enhance motor ability or to counterbalance disability or disease. KEY POINTS: We studied the effect of chemically induced random mutations on mouse motor performance. An array of mutations influenced the rate of motor learning. DNA regulation genes predominated among these mutant loci. Several mutations in unsuspected genes led to superperformance. Assuming little-biased mutagenicity, the results allow for an estimation of the probability for any spontaneous mutation to influence a behaviour such as motor learning and ultimate performance.
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Affiliation(s)
- Vikram Jakkamsetti
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Qian Ma
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Gustavo Angulo
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - William Scudder
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Bruce Beutler
- Center for Genetics of Host Defense, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Immunology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Juan M. Pascual
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Physiology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Pediatrics, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Eugene McDermott Center for Human Growth & Development / Center for Human Genetics, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
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3
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Dumont BL, Gatti DM, Ballinger MA, Lin D, Phifer-Rixey M, Sheehan MJ, Suzuki TA, Wooldridge LK, Frempong HO, Lawal RA, Churchill GA, Lutz C, Rosenthal N, White JK, Nachman MW. Into the Wild: A novel wild-derived inbred strain resource expands the genomic and phenotypic diversity of laboratory mouse models. PLoS Genet 2024; 20:e1011228. [PMID: 38598567 PMCID: PMC11034653 DOI: 10.1371/journal.pgen.1011228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 04/22/2024] [Accepted: 03/18/2024] [Indexed: 04/12/2024] Open
Abstract
The laboratory mouse has served as the premier animal model system for both basic and preclinical investigations for over a century. However, laboratory mice capture only a subset of the genetic variation found in wild mouse populations, ultimately limiting the potential of classical inbred strains to uncover phenotype-associated variants and pathways. Wild mouse populations are reservoirs of genetic diversity that could facilitate the discovery of new functional and disease-associated alleles, but the scarcity of commercially available, well-characterized wild mouse strains limits their broader adoption in biomedical research. To overcome this barrier, we have recently developed, sequenced, and phenotyped a set of 11 inbred strains derived from wild-caught Mus musculus domesticus. Each of these "Nachman strains" immortalizes a unique wild haplotype sampled from one of five environmentally distinct locations across North and South America. Whole genome sequence analysis reveals that each strain carries between 4.73-6.54 million single nucleotide differences relative to the GRCm39 mouse reference, with 42.5% of variants in the Nachman strain genomes absent from current classical inbred mouse strain panels. We phenotyped the Nachman strains on a customized pipeline to assess the scope of disease-relevant neurobehavioral, biochemical, physiological, metabolic, and morphological trait variation. The Nachman strains exhibit significant inter-strain variation in >90% of 1119 surveyed traits and expand the range of phenotypic diversity captured in classical inbred strain panels. These novel wild-derived inbred mouse strain resources are set to empower new discoveries in both basic and preclinical research.
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Affiliation(s)
- Beth L. Dumont
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine, United States of America
- Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, United States of America
- Graduate School of Biomedical Science and Engineering, The University of Maine, Orono, Maine, United States of America
| | - Daniel M. Gatti
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine, United States of America
| | - Mallory A. Ballinger
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, United States of America
| | - Dana Lin
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Megan Phifer-Rixey
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, United States of America
| | - Michael J. Sheehan
- Department of Neurobiology and Behavior, Cornell University, Ithaca, New York, United States of America
| | - Taichi A. Suzuki
- College of Health Solutions and Biodesign Center for Health Through Microbiomes, Arizona State University, Tempe, Arizona, United States of America
| | - Lydia K. Wooldridge
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine, United States of America
| | - Hilda Opoku Frempong
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine, United States of America
- Graduate School of Biomedical Science and Engineering, The University of Maine, Orono, Maine, United States of America
| | - Raman Akinyanju Lawal
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine, United States of America
| | - Gary A. Churchill
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine, United States of America
- Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, United States of America
- Graduate School of Biomedical Science and Engineering, The University of Maine, Orono, Maine, United States of America
| | - Cathleen Lutz
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine, United States of America
| | - Nadia Rosenthal
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine, United States of America
- Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, United States of America
- Graduate School of Biomedical Science and Engineering, The University of Maine, Orono, Maine, United States of America
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Jacqueline K. White
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine, United States of America
| | - Michael W. Nachman
- Department of Integrative Biology, Museum of Vertebrate Zoology, and Center for Computational Biology, University of California, Berkeley, Berkeley, California, United States of America
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4
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Sasani TA, Quinlan AR, Harris K. Epistasis between mutator alleles contributes to germline mutation spectrum variability in laboratory mice. eLife 2024; 12:RP89096. [PMID: 38381482 PMCID: PMC10942616 DOI: 10.7554/elife.89096] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024] Open
Abstract
Maintaining germline genome integrity is essential and enormously complex. Although many proteins are involved in DNA replication, proofreading, and repair, mutator alleles have largely eluded detection in mammals. DNA replication and repair proteins often recognize sequence motifs or excise lesions at specific nucleotides. Thus, we might expect that the spectrum of de novo mutations - the frequencies of C>T, A>G, etc. - will differ between genomes that harbor either a mutator or wild-type allele. Previously, we used quantitative trait locus mapping to discover candidate mutator alleles in the DNA repair gene Mutyh that increased the C>A germline mutation rate in a family of inbred mice known as the BXDs (Sasani et al., 2022, Ashbrook et al., 2021). In this study we developed a new method to detect alleles associated with mutation spectrum variation and applied it to mutation data from the BXDs. We discovered an additional C>A mutator locus on chromosome 6 that overlaps Ogg1, a DNA glycosylase involved in the same base-excision repair network as Mutyh (David et al., 2007). Its effect depends on the presence of a mutator allele near Mutyh, and BXDs with mutator alleles at both loci have greater numbers of C>A mutations than those with mutator alleles at either locus alone. Our new methods for analyzing mutation spectra reveal evidence of epistasis between germline mutator alleles and may be applicable to mutation data from humans and other model organisms.
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Affiliation(s)
- Thomas A Sasani
- Department of Human Genetics, University of UtahSalt Lake CityUnited States
| | - Aaron R Quinlan
- Department of Human Genetics, University of UtahSalt Lake CityUnited States
- Department of Biomedical Informatics, University of UtahSalt Lake CityUnited States
| | - Kelley Harris
- Department of Genome Sciences, University of WashingtonSeattleUnited States
- Herbold Computational Biology Program, Fred Hutch Cancer CenterSeattleUnited States
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5
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Sasani TA, Quinlan AR, Harris K. Epistasis between mutator alleles contributes to germline mutation spectra variability in laboratory mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.25.537217. [PMID: 37162999 PMCID: PMC10168256 DOI: 10.1101/2023.04.25.537217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Maintaining germline genome integrity is essential and enormously complex. Although many proteins are involved in DNA replication, proofreading, and repair [1], mutator alleles have largely eluded detection in mammals. DNA replication and repair proteins often recognize sequence motifs or excise lesions at specific nucleotides. Thus, we might expect that the spectrum of de novo mutations - the frequencies of C>T, A>G, etc. - will differ between genomes that harbor either a mutator or wild-type allele. Previously, we used quantitative trait locus mapping to discover candidate mutator alleles in the DNA repair gene Mutyh that increased the C>A germline mutation rate in a family of inbred mice known as the BXDs [2,3]. In this study we developed a new method to detect alleles associated with mutation spectrum variation and applied it to mutation data from the BXDs. We discovered an additional C>A mutator locus on chromosome 6 that overlaps Ogg1, a DNA glycosylase involved in the same base-excision repair network as Mutyh [4]. Its effect depended on the presence of a mutator allele near Mutyh, and BXDs with mutator alleles at both loci had greater numbers of C>A mutations than those with mutator alleles at either locus alone. Our new methods for analyzing mutation spectra reveal evidence of epistasis between germline mutator alleles and may be applicable to mutation data from humans and other model organisms.
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Affiliation(s)
| | - Aaron R. Quinlan
- Department of Human Genetics, University of Utah; Department of Biomedical Informatics, University of Utah · Funded by NIH/NHGRI R01HG012252
| | - Kelley Harris
- Department of Genome Sciences, University of Washington · Funded by NIH/NIGMS R35GM133428; Burroughs Wellcome Career Award at the Scientific Interface; Searle Scholarship; Pew Scholarship; Sloan Fellowship; Allen Discovery Center for Cell Lineage Tracing
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6
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Beichman AC, Robinson J, Lin M, Moreno-Estrada A, Nigenda-Morales S, Harris K. Evolution of the Mutation Spectrum Across a Mammalian Phylogeny. Mol Biol Evol 2023; 40:msad213. [PMID: 37770035 PMCID: PMC10566577 DOI: 10.1093/molbev/msad213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 08/21/2023] [Accepted: 09/19/2023] [Indexed: 10/03/2023] Open
Abstract
Although evolutionary biologists have long theorized that variation in DNA repair efficacy might explain some of the diversity of lifespan and cancer incidence across species, we have little data on the variability of normal germline mutagenesis outside of humans. Here, we shed light on the spectrum and etiology of mutagenesis across mammals by quantifying mutational sequence context biases using polymorphism data from thirteen species of mice, apes, bears, wolves, and cetaceans. After normalizing the mutation spectrum for reference genome accessibility and k-mer content, we use the Mantel test to deduce that mutation spectrum divergence is highly correlated with genetic divergence between species, whereas life history traits like reproductive age are weaker predictors of mutation spectrum divergence. Potential bioinformatic confounders are only weakly related to a small set of mutation spectrum features. We find that clock-like mutational signatures previously inferred from human cancers cannot explain the phylogenetic signal exhibited by the mammalian mutation spectrum, despite the ability of these signatures to fit each species' 3-mer spectrum with high cosine similarity. In contrast, parental aging signatures inferred from human de novo mutation data appear to explain much of the 1-mer spectrum's phylogenetic signal in combination with a novel mutational signature. We posit that future models purporting to explain the etiology of mammalian mutagenesis need to capture the fact that more closely related species have more similar mutation spectra; a model that fits each marginal spectrum with high cosine similarity is not guaranteed to capture this hierarchy of mutation spectrum variation among species.
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Affiliation(s)
- Annabel C Beichman
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Jacqueline Robinson
- Institute for Human Genetics, University of California, San Francisco, CA, USA
| | - Meixi Lin
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - Andrés Moreno-Estrada
- National Laboratory of Genomics for Biodiversity, Advanced Genomics Unit (UGA-LANGEBIO), CINVESTAV, Irapuato, Mexico
| | - Sergio Nigenda-Morales
- Department of Biological Sciences, California State University, San Marcos, San Marcos, CA, USA
| | - Kelley Harris
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Herbold Computational Biology Program, Fred Hutchinson Cancer Center, Seattle, WA, USA
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7
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Dumont BL, Gatti D, Ballinger MA, Lin D, Phifer-Rixey M, Sheehan MJ, Suzuki TA, Wooldridge LK, Frempong HO, Churchill G, Lutz C, Rosenthal N, White JK, Nachman MW. Into the Wild: A novel wild-derived inbred strain resource expands the genomic and phenotypic diversity of laboratory mouse models. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.21.558738. [PMID: 37790321 PMCID: PMC10542534 DOI: 10.1101/2023.09.21.558738] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
The laboratory mouse has served as the premier animal model system for both basic and preclinical investigations for a century. However, laboratory mice capture a narrow subset of the genetic variation found in wild mouse populations. This consideration inherently restricts the scope of potential discovery in laboratory models and narrows the pool of potentially identified phenotype-associated variants and pathways. Wild mouse populations are reservoirs of predicted functional and disease-associated alleles, but the sparsity of commercially available, well-characterized wild mouse strains limits their broader adoption in biomedical research. To overcome this barrier, we have recently imported, sequenced, and phenotyped a set of 11 wild-derived inbred strains developed from wild-caught Mus musculus domesticus. Each of these "Nachman strains" immortalizes a unique wild haplotype sampled from five environmentally diverse locations across North and South America: Saratoga Springs, New York, USA; Gainesville, Florida, USA; Manaus, Brazil; Tucson, Arizona, USA; and Edmonton, Alberta, Canada. Whole genome sequence analysis reveals that each strain carries between 4.73-6.54 million single nucleotide differences relative to the mouse reference assembly, with 42.5% of variants in the Nachman strain genomes absent from classical inbred mouse strains. We phenotyped the Nachman strains on a customized pipeline to assess the scope of disease-relevant neurobehavioral, biochemical, physiological, metabolic, and morphological trait variation. The Nachman strains exhibit significant inter-strain variation in >90% of 1119 surveyed traits and expand the range of phenotypic diversity captured in classical inbred strain panels alone. Taken together, our work introduces a novel wild-derived inbred mouse strain resource that will enable new discoveries in basic and preclinical research. These strains are currently available through The Jackson Laboratory Repository under laboratory code NachJ.
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Affiliation(s)
- Beth L Dumont
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME, 04609, USA
- Tufts University, Graduate School of Biomedical Sciences, 136 Harrison Ave, Boston, MA, 02111, USA
- The University of Maine, Graduate School of Biomedical Science and Engineering, 5775 Stodder Hall, Room 46, Orono, ME, 04469, USA
| | - Daniel Gatti
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME, 04609, USA
| | - Mallory A Ballinger
- Department of Integrative Biology, Center for Computational Biology, and Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Dana Lin
- Department of Integrative Biology, Center for Computational Biology, and Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA 94720, USA
| | | | - Michael J Sheehan
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - Taichi A Suzuki
- College of Health Solutions and Biodesign Center for Health Through Microbiomes, Arizona State University, Tempe, AZ, USA 85281
| | | | - Hilda Opoku Frempong
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME, 04609, USA
- The University of Maine, Graduate School of Biomedical Science and Engineering, 5775 Stodder Hall, Room 46, Orono, ME, 04469, USA
| | - Gary Churchill
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME, 04609, USA
- Tufts University, Graduate School of Biomedical Sciences, 136 Harrison Ave, Boston, MA, 02111, USA
- The University of Maine, Graduate School of Biomedical Science and Engineering, 5775 Stodder Hall, Room 46, Orono, ME, 04469, USA
| | - Cathleen Lutz
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME, 04609, USA
| | - Nadia Rosenthal
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME, 04609, USA
- Tufts University, Graduate School of Biomedical Sciences, 136 Harrison Ave, Boston, MA, 02111, USA
- The University of Maine, Graduate School of Biomedical Science and Engineering, 5775 Stodder Hall, Room 46, Orono, ME, 04469, USA
| | | | - Michael W Nachman
- Department of Integrative Biology, Center for Computational Biology, and Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA 94720, USA
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8
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Pflughaupt P, Sahakyan AB. Generalised interrelations among mutation rates drive the genomic compliance of Chargaff's second parity rule. Nucleic Acids Res 2023; 51:7409-7423. [PMID: 37293966 PMCID: PMC10415130 DOI: 10.1093/nar/gkad477] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 05/05/2023] [Accepted: 05/17/2023] [Indexed: 06/10/2023] Open
Abstract
Chargaff's second parity rule (PR-2), where the complementary base and k-mer contents are matching within the same strand of a double stranded DNA (dsDNA), is a phenomenon that invited many explanations. The strict compliance of nearly all nuclear dsDNA to PR-2 implies that the explanation should also be similarly adamant. In this work, we revisited the possibility of mutation rates driving PR-2 compliance. Starting from the assumption-free approach, we constructed kinetic equations for unconstrained simulations. The results were analysed for their PR-2 compliance by employing symbolic regression and machine learning techniques. We arrived to a generalised set of mutation rate interrelations in place in most species that allow for their full PR-2 compliance. Importantly, our constraints explain PR-2 in genomes out of the scope of the prior explanations based on the equilibration under mutation rates with simpler no-strand-bias constraints. We thus reinstate the role of mutation rates in PR-2 through its molecular core, now shown, under our formulation, to be tolerant to previously noted strand biases and incomplete compositional equilibration. We further investigate the time for any genome to reach PR-2, showing that it is generally earlier than the compositional equilibrium, and well within the age of life on Earth.
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Affiliation(s)
- Patrick Pflughaupt
- MRC WIMM Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Aleksandr B Sahakyan
- MRC WIMM Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DS, UK
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9
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Jakkamsetti V, Ma Q, Angulo G, Scudder W, Beutler B, Pascual JM. Genetic influences on motor learning and superperformance mutants revealed by random mutational survey of mouse locomotion. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.28.546756. [PMID: 37425744 PMCID: PMC10327015 DOI: 10.1101/2023.06.28.546756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Evolution depends upon genetic variations that influence physiology. As defined in a genetic screen, phenotypic performance may be enhanced or degraded by such mutations. We set out to detect mutations that influence motor function, including motor learning. Thus, we tested the motor effects of 36,444 non-synonymous coding/splicing mutations induced in the germline of C57BL/6J mice with N-ethyl-N-nitrosourea by measuring changes in the performance of repetitive rotarod trials while blinded to genotype. Automated meiotic mapping was used to implicate individual mutations in causation. 32,726 mice bearing all the variant alleles were screened. This was complemented with the simultaneous testing of 1,408 normal mice for reference. 16.3% of autosomal genes were thus rendered detectably hypomorphic or nullified by mutations in homozygosity and motor tested in at least 3 mice. This approach allowed us to identify superperformance mutations in Rif1, Tk1, Fan1 and Mn1. These genes are primarily related, among other less well characterized functions, to nucleic acid biology. We also associated distinct motor learning patterns with groups of functionally related genes. These functional sets included preferentially histone H3 methyltransferase activity for mice that learnt at an accelerated rate relative to the rest of mutant mice. The results allow for an estimation of the fraction of mutations that can modify a behavior influential for evolution such as locomotion. They may also enable, once the loci are further validated and the mechanisms elucidated, the harnessing of the activity of the newly identified genes to enhance motor ability or to counterbalance disability or disease.
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Affiliation(s)
- Vikram Jakkamsetti
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Qian Ma
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Gustavo Angulo
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - William Scudder
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Bruce Beutler
- Center for Genetics of Host Defense, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Immunology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Juan M. Pascual
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Physiology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Pediatrics, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Eugene McDermott Center for Human Growth & Development / Center for Human Genetics, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
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10
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Beichman AC, Robinson J, Lin M, Moreno-Estrada A, Nigenda-Morales S, Harris K. "Evolution of the mutation spectrum across a mammalian phylogeny". BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.31.543114. [PMID: 37398383 PMCID: PMC10312511 DOI: 10.1101/2023.05.31.543114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Little is known about how the spectrum and etiology of germline mutagenesis might vary among mammalian species. To shed light on this mystery, we quantify variation in mutational sequence context biases using polymorphism data from thirteen species of mice, apes, bears, wolves, and cetaceans. After normalizing the mutation spectrum for reference genome accessibility and k -mer content, we use the Mantel test to deduce that mutation spectrum divergence is highly correlated with genetic divergence between species, whereas life history traits like reproductive age are weaker predictors of mutation spectrum divergence. Potential bioinformatic confounders are only weakly related to a small set of mutation spectrum features. We find that clocklike mutational signatures previously inferred from human cancers cannot explain the phylogenetic signal exhibited by the mammalian mutation spectrum, despite the ability of these clocklike signatures to fit each species' 3-mer spectrum with high cosine similarity. In contrast, parental aging signatures inferred from human de novo mutation data appear to explain much of the mutation spectrum's phylogenetic signal when fit to non-context-dependent mutation spectrum data in combination with a novel mutational signature. We posit that future models purporting to explain the etiology of mammalian mutagenesis need to capture the fact that more closely related species have more similar mutation spectra; a model that fits each marginal spectrum with high cosine similarity is not guaranteed to capture this hierarchy of mutation spectrum variation among species.
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Affiliation(s)
| | - Jacqueline Robinson
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA
| | - Meixi Lin
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA
| | - Andrés Moreno-Estrada
- National Laboratory of Genomics for Biodiversity, Advanced Genomics Unit (UGA-LANGEBIO), CINVESTAV, Irapuato, Mexico
| | - Sergio Nigenda-Morales
- Department of Biological Sciences, California State University, San Marcos, San Marcos CA
| | - Kelley Harris
- Department of Genome Sciences, University of Washington, Seattle WA
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11
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Fonager SV, Winther G, Wittenborn TR, Jensen L, Fahlquist-Hagert C, Hansen LA, Füchtbauer EM, Romero-Ramos M, Degn SE. Increased maternofoetal transfer of antibodies in a murine model of systemic lupus erythematosus, but no immune activation and neuroimmune sequelae in offspring. J Neuroimmunol 2022; 370:577927. [PMID: 35858501 DOI: 10.1016/j.jneuroim.2022.577927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 05/27/2022] [Accepted: 07/09/2022] [Indexed: 10/17/2022]
Abstract
Maternally transferred autoantibodies can negatively impact the development and health of offspring, increasing the risk of neurodevelopmental disorders. We used embryo transfers to examine maternofoetal immune imprinting in the autoimmune BXSB/MpJ mouse model. Anti-double-stranded DNA antibodies and total immunoglobulins were measured, using allotypes of the IgG subclass to distinguish maternally transferred antibodies from those produced endogenously. Frequencies of germinal center and plasma cells were analysed by flow cytometry. Microglial morphology in offspring CNS was assessed using immunohistochemistry. In contrast to prior findings, our results indicate that BXSB/MpJ mothers display a mild autoimmune phenotype, which does not significantly impact the offspring.
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Affiliation(s)
- Sofie Vestergaard Fonager
- Department of Biomedicine, Aarhus University, Denmark; Department of Molecular Biology and Genetics, Aarhus University, Denmark
| | | | | | | | | | | | | | - Marina Romero-Ramos
- Department of Biomedicine, Aarhus University, Denmark; DANDRITE, Danish Research Institute of Translational Neuroscience, Aarhus University, 8000, Aarhus C, Denmark
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12
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Sasani TA, Ashbrook DG, Beichman AC, Lu L, Palmer AA, Williams RW, Pritchard JK, Harris K. A natural mutator allele shapes mutation spectrum variation in mice. Nature 2022; 605:497-502. [PMID: 35545679 PMCID: PMC9272728 DOI: 10.1038/s41586-022-04701-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 03/25/2022] [Indexed: 12/12/2022]
Abstract
Although germline mutation rates and spectra can vary within and between species, common genetic modifiers of the mutation rate have not been identified in nature1. Here we searched for loci that influence germline mutagenesis using a uniquely powerful resource: a panel of recombinant inbred mouse lines known as the BXD, descended from the laboratory strains C57BL/6J (B haplotype) and DBA/2J (D haplotype). Each BXD lineage has been maintained by brother-sister mating in the near absence of natural selection, accumulating de novo mutations for up to 50 years on a known genetic background that is a unique linear mosaic of B and D haplotypes2. We show that mice inheriting D haplotypes at a quantitative trait locus on chromosome 4 accumulate C>A germline mutations at a 50% higher rate than those inheriting B haplotypes, primarily owing to the activity of a C>A-dominated mutational signature known as SBS18. The B and D quantitative trait locus haplotypes encode different alleles of Mutyh, a DNA repair gene that underlies the heritable cancer predisposition syndrome that causes colorectal tumors with a high SBS18 mutation load3,4. Both B and D Mutyh alleles are present in wild populations of Mus musculus domesticus, providing evidence that common genetic variation modulates germline mutagenesis in a model mammalian species.
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Affiliation(s)
- Thomas A Sasani
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - David G Ashbrook
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Annabel C Beichman
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Lu Lu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Abraham A Palmer
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - Robert W Williams
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Jonathan K Pritchard
- Department of Genetics, Stanford University, Stanford, CA, USA
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Kelley Harris
- Department of Genome Sciences, University of Washington, Seattle, WA, USA.
- Computational Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
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13
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Jiang P, Ollodart AR, Sudhesh V, Herr AJ, Dunham MJ, Harris K. A modified fluctuation assay reveals a natural mutator phenotype that drives mutation spectrum variation within Saccharomyces cerevisiae. eLife 2021; 10:68285. [PMID: 34523420 PMCID: PMC8497059 DOI: 10.7554/elife.68285] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 09/14/2021] [Indexed: 12/23/2022] Open
Abstract
Although studies of Saccharomyces cerevisiae have provided many insights into mutagenesis and DNA repair, most of this work has focused on a few laboratory strains. Much less is known about the phenotypic effects of natural variation within S. cerevisiae’s DNA repair pathways. Here, we use natural polymorphisms to detect historical mutation spectrum differences among several wild and domesticated S. cerevisiae strains. To determine whether these differences are likely caused by genetic mutation rate modifiers, we use a modified fluctuation assay with a CAN1 reporter to measure de novo mutation rates and spectra in 16 of the analyzed strains. We measure a 10-fold range of mutation rates and identify two strains with distinctive mutation spectra. These strains, known as AEQ and AAR, come from the panel’s ‘Mosaic beer’ clade and share an enrichment for C > A mutations that is also observed in rare variation segregating throughout the genomes of several Mosaic beer and Mixed origin strains. Both AEQ and AAR are haploid derivatives of the diploid natural isolate CBS 1782, whose rare polymorphisms are enriched for C > A as well, suggesting that the underlying mutator allele is likely active in nature. We use a plasmid complementation test to show that AAR and AEQ share a mutator allele in the DNA repair gene OGG1, which excises 8-oxoguanine lesions that can cause C > A mutations if left unrepaired.
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Affiliation(s)
- Pengyao Jiang
- Department of Genome Sciences, University of Washington, Seattle, United States
| | - Anja R Ollodart
- Department of Genome Sciences, University of Washington, Seattle, United States.,Molecular and Cellular Biology Program, University of Washington, Seattle, United States
| | - Vidha Sudhesh
- Department of Genome Sciences, University of Washington, Seattle, United States
| | - Alan J Herr
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, United States
| | - Maitreya J Dunham
- Department of Genome Sciences, University of Washington, Seattle, United States
| | - Kelley Harris
- Department of Genome Sciences, University of Washington, Seattle, United States.,Department of Computational Biology, Fred Hutchinson Cancer Research Center, Seattle, United States
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14
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López-Cortegano E, Craig RJ, Chebib J, Samuels T, Morgan AD, Kraemer SA, Böndel KB, Ness RW, Colegrave N, Keightley PD. De Novo Mutation Rate Variation and Its Determinants in Chlamydomonas. Mol Biol Evol 2021; 38:3709-3723. [PMID: 33950243 PMCID: PMC8383909 DOI: 10.1093/molbev/msab140] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
De novo mutations are central for evolution, since they provide the raw material for natural selection by regenerating genetic variation. However, studying de novo mutations is challenging and is generally restricted to model species, so we have a limited understanding of the evolution of the mutation rate and spectrum between closely related species. Here, we present a mutation accumulation (MA) experiment to study de novo mutation in the unicellular green alga Chlamydomonas incerta and perform comparative analyses with its closest known relative, Chlamydomonas reinhardtii. Using whole-genome sequencing data, we estimate that the median single nucleotide mutation (SNM) rate in C. incerta is μ = 7.6 × 10-10, and is highly variable between MA lines, ranging from μ = 0.35 × 10-10 to μ = 131.7 × 10-10. The SNM rate is strongly positively correlated with the mutation rate for insertions and deletions between lines (r > 0.97). We infer that the genomic factors associated with variation in the mutation rate are similar to those in C. reinhardtii, allowing for cross-prediction between species. Among these genomic factors, sequence context and complexity are more important than GC content. With the exception of a remarkably high C→T bias, the SNM spectrum differs markedly between the two Chlamydomonas species. Our results suggest that similar genomic and biological characteristics may result in a similar mutation rate in the two species, whereas the SNM spectrum has more freedom to diverge.
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Affiliation(s)
- Eugenio López-Cortegano
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Rory J Craig
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Jobran Chebib
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Toby Samuels
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Andrew D Morgan
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Katharina B Böndel
- Institute of Plant Breeding, Seed Science and Population Genetics, University of Hohenheim, Stuttgart, Germany
| | - Rob W Ness
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada
| | - Nick Colegrave
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Peter D Keightley
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
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15
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DeWitt WS, Harris KD, Ragsdale AP, Harris K. Nonparametric coalescent inference of mutation spectrum history and demography. Proc Natl Acad Sci U S A 2021; 118:e2013798118. [PMID: 34016747 PMCID: PMC8166128 DOI: 10.1073/pnas.2013798118] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
As populations boom and bust, the accumulation of genetic diversity is modulated, encoding histories of living populations in present-day variation. Many methods exist to decode these histories, and all must make strong model assumptions. It is typical to assume that mutations accumulate uniformly across the genome at a constant rate that does not vary between closely related populations. However, recent work shows that mutational processes in human and great ape populations vary across genomic regions and evolve over time. This perturbs the mutation spectrum (relative mutation rates in different local nucleotide contexts). Here, we develop theoretical tools in the framework of Kingman's coalescent to accommodate mutation spectrum dynamics. We present mutation spectrum history inference (mushi), a method to perform nonparametric inference of demographic and mutation spectrum histories from allele frequency data. We use mushi to reconstruct trajectories of effective population size and mutation spectrum divergence between human populations, identify mutation signatures and their dynamics in different human populations, and calibrate the timing of a previously reported mutational pulse in the ancestors of Europeans. We show that mutation spectrum histories can be placed in a well-studied theoretical setting and rigorously inferred from genomic variation data, like other features of evolutionary history.
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Affiliation(s)
- William S DeWitt
- Department of Genome Sciences, University of Washington, Seattle, WA 98195;
- Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109
| | - Kameron Decker Harris
- Paul G. Allen School of Computer Science & Engineering, University of Washington, Seattle, WA 98195
- Department of Biology, University of Washington, Seattle, WA 98195
| | - Aaron P Ragsdale
- National Laboratory of Genomics for Biodiversity, Unit of Advanced Genomics, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Irapuato, Mexico 36821
| | - Kelley Harris
- Department of Genome Sciences, University of Washington, Seattle, WA 98195;
- Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109
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16
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Hochberg GKA, Liu Y, Marklund EG, Metzger BPH, Laganowsky A, Thornton JW. A hydrophobic ratchet entrenches molecular complexes. Nature 2020; 588:503-508. [PMID: 33299178 PMCID: PMC8168016 DOI: 10.1038/s41586-020-3021-2] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 10/20/2020] [Indexed: 02/07/2023]
Abstract
Most proteins assemble into multisubunit complexes1. The persistence of these complexes across evolutionary time is usually explained as the result of natural selection for functional properties that depend on multimerization, such as intersubunit allostery or the capacity to do mechanical work2. In many complexes, however, multimerization does not enable any known function3. An alternative explanation is that multimers could become entrenched if substitutions accumulate that are neutral in multimers but deleterious in monomers; purifying selection would then prevent reversion to the unassembled form, even if assembly per se does not enhance biological function3-7. Here we show that a hydrophobic mutational ratchet systematically entrenches molecular complexes. By applying ancestral protein reconstruction and biochemical assays to the evolution of steroid hormone receptors, we show that an ancient hydrophobic interface, conserved for hundreds of millions of years, is entrenched because exposure of this interface to solvent reduces protein stability and causes aggregation, even though the interface makes no detectable contribution to function. Using structural bioinformatics, we show that a universal mutational propensity drives sites that are buried in multimeric interfaces to accumulate hydrophobic substitutions to levels that are not tolerated in monomers. In a database of hundreds of families of multimers, most show signatures of long-term hydrophobic entrenchment. It is therefore likely that many protein complexes persist because a simple ratchet-like mechanism entrenches them across evolutionary time, even when they are functionally gratuitous.
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Affiliation(s)
- Georg K A Hochberg
- Department of Ecology and Evolution, University of Chicago, Chicago, IL, USA
| | - Yang Liu
- Department of Chemistry, Texas A&M University, College Station, TX, USA
| | - Erik G Marklund
- Department of Chemistry - BMC, Uppsala University, Uppsala, Sweden
| | - Brian P H Metzger
- Department of Ecology and Evolution, University of Chicago, Chicago, IL, USA
| | - Arthur Laganowsky
- Department of Chemistry, Texas A&M University, College Station, TX, USA
| | - Joseph W Thornton
- Department of Ecology and Evolution, University of Chicago, Chicago, IL, USA.
- Department of Human Genetics, University of Chicago, Chicago, IL, USA.
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17
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Inbred lab mice are not isogenic: genetic variation within inbred strains used to infer the mutation rate per nucleotide site. Heredity (Edinb) 2020; 126:107-116. [PMID: 32868871 PMCID: PMC7852876 DOI: 10.1038/s41437-020-00361-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 08/20/2020] [Accepted: 08/21/2020] [Indexed: 12/14/2022] Open
Abstract
For over a century, inbred mice have been used in many areas of genetics research to gain insight into the genetic variation underlying traits of interest. The generalizability of any genetic research study in inbred mice is dependent upon all individual mice being genetically identical, which in turn is dependent on the breeding designs of companies that supply inbred mice to researchers. Here, we compare whole-genome sequences from individuals of four commonly used inbred strains that were procured from either the colony nucleus or from a production colony (which can be as many as ten generations removed from the nucleus) of a large commercial breeder, in order to investigate the extent and nature of genetic variation within and between individuals. We found that individuals within strains are not isogenic, and there are differences in the levels of genetic variation that are explained by differences in the genetic distance from the colony nucleus. In addition, we employ a novel approach to mutation rate estimation based on the observed genetic variation and the expected site frequency spectrum at equilibrium, given a fully inbred breeding design. We find that it provides a reasonable per nucleotide mutation rate estimate when mice come from the colony nucleus (~7.9 × 10−9 in C3H/HeN), but substantially inflated estimates when mice come from production colonies.
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18
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Carlson J, DeWitt WS, Harris K. Inferring evolutionary dynamics of mutation rates through the lens of mutation spectrum variation. Curr Opin Genet Dev 2020; 62:50-57. [PMID: 32619789 DOI: 10.1016/j.gde.2020.05.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 05/13/2020] [Accepted: 05/22/2020] [Indexed: 01/04/2023]
Abstract
There are many possible failure points in the transmission of genetic information that can produce heritable germline mutations. Once a mutation has been passed from parents to offspring for several generations, it can be difficult or impossible to identify its root cause; however, sometimes the nature of the ancestral and derived DNA sequences can provide mechanistic clues about a genetic change that happened hundreds or thousands of generations ago. Here, we review evidence that the sequence context 'spectrum' of germline mutagenesis has been evolving surprisingly rapidly over the history of humans and other species. We go on to discuss possible causal factors that might underlie rapid mutation spectrum evolution.
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Affiliation(s)
- Jedidiah Carlson
- Department of Genome Sciences, Foege Hall, University of Washington, Seattle, WA 98105, United States
| | - William S DeWitt
- Department of Genome Sciences, Foege Hall, University of Washington, Seattle, WA 98105, United States; Computational Biology Program, Fred Hutchinson Cancer Research Center, 1100 Eastlake Ave E, Seattle, WA 98109, United States
| | - Kelley Harris
- Department of Genome Sciences, Foege Hall, University of Washington, Seattle, WA 98105, United States; Computational Biology Program, Fred Hutchinson Cancer Research Center, 1100 Eastlake Ave E, Seattle, WA 98109, United States.
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