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Davison A, Chowdhury M, Johansen M, Uliano-Silva M, Blaxter M. High heteroplasmy is associated with low mitochondrial copy number and selection against non-synonymous mutations in the snail Cepaea nemoralis. BMC Genomics 2024; 25:596. [PMID: 38872121 DOI: 10.1186/s12864-024-10505-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 06/06/2024] [Indexed: 06/15/2024] Open
Abstract
Molluscan mitochondrial genomes are unusual because they show wide variation in size, radical genome rearrangements and frequently show high variation (> 10%) within species. As progress in understanding this variation has been limited, we used whole genome sequencing of a six-generation matriline of the terrestrial snail Cepaea nemoralis, as well as whole genome sequences from wild-collected C. nemoralis, the sister species C. hortensis, and multiple other snail species to explore the origins of mitochondrial DNA (mtDNA) variation. The main finding is that a high rate of SNP heteroplasmy in somatic tissue was negatively correlated with mtDNA copy number in both Cepaea species. In individuals with under ten mtDNA copies per nuclear genome, more than 10% of all positions were heteroplasmic, with evidence for transmission of this heteroplasmy through the germline. Further analyses showed evidence for purifying selection acting on non-synonymous mutations, even at low frequency of the rare allele, especially in cytochrome oxidase subunit 1 and cytochrome b. The mtDNA of some individuals of Cepaea nemoralis contained a length heteroplasmy, including up to 12 direct repeat copies of tRNA-Val, with 24 copies in another snail, Candidula rugosiuscula, and repeats of tRNA-Thr in C. hortensis. These repeats likely arise due to error prone replication but are not correlated with mitochondrial copy number in C. nemoralis. Overall, the findings provide key insights into mechanisms of replication, mutation and evolution in molluscan mtDNA, and so will inform wider studies on the biology and evolution of mtDNA across animal phyla.
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Affiliation(s)
- Angus Davison
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
| | - Mehrab Chowdhury
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Margrethe Johansen
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Marcela Uliano-Silva
- Tree of Life, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, Cambridgeshire, CB10 1SA, UK
| | - Mark Blaxter
- Tree of Life, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, Cambridgeshire, CB10 1SA, UK
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Patterson EC, Lall GM, Neumann R, Ottolini B, Batini C, Sacchini F, Foster AP, Wetton JH, Jobling MA. Mitogenome sequences of domestic cats demonstrate lineage expansions and dynamic mutation processes in a mitochondrial minisatellite. BMC Genomics 2023; 24:690. [PMID: 37978434 PMCID: PMC10655372 DOI: 10.1186/s12864-023-09789-1] [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: 06/23/2023] [Accepted: 11/06/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND As a population genetic tool, mitochondrial DNA is commonly divided into the ~ 1-kb control region (CR), in which single nucleotide variant (SNV) diversity is relatively high, and the coding region, in which selective constraint is greater and diversity lower, but which provides an informative phylogeny. In some species, the CR contains variable tandemly repeated sequences that are understudied due to heteroplasmy. Domestic cats (Felis catus) have a recent origin and therefore traditional CR-based analysis of populations yields only a small number of haplotypes. RESULTS To increase resolution we used Nanopore sequencing to analyse 119 cat mitogenomes via a long-amplicon approach. This greatly improves discrimination (from 15 to 87 distinct haplotypes in our dataset) and defines a phylogeny showing similar starlike topologies within all major clades (haplogroups), likely reflecting post-domestication expansion. We sequenced RS2, a CR tandem array of 80-bp repeat units, placing RS2 array structures within the phylogeny and increasing overall haplotype diversity. Repeat number varies between 3 and 12 (median: 4) with over 30 different repeat unit types differing largely by SNVs. Five SNVs show evidence of independent recurrence within the phylogeny, and seven are involved in at least 11 instances of rapid spread along repeat arrays within haplogroups. CONCLUSIONS In defining mitogenome variation our study provides key information for the forensic genetic analysis of cat hair evidence, and for the first time a phylogenetically informed picture of tandem repeat variation that reveals remarkably dynamic mutation processes at work in the mitochondrion.
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Affiliation(s)
- Emily C Patterson
- Department of Genetics & Genome Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - Gurdeep Matharu Lall
- Department of Genetics & Genome Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - Rita Neumann
- Department of Genetics & Genome Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - Barbara Ottolini
- Department of Genetics & Genome Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK
- Present Address: Oxford Nanopore Technologies Plc., Oxford Science Park, Edmund Halley Rd, Oxford, OX4 4DQ, UK
| | - Chiara Batini
- Department of Genetics & Genome Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK
- Present Address: Department of Population Health Sciences, University of Leicester, Leicester, UK
- Biomedical Research Centre, Leicester National Institute for Health and Care Research, Glenfield Hospital, Leicester, UK
| | - Federico Sacchini
- IDEXX Laboratories Italia S.R.L., Via Guglielmo Silva, 36-20149, Milano, MI, Italy
| | - Aiden P Foster
- Bristol Veterinary School, University of Bristol, Langford House, Langford, BS40 5DU, North Somerset, UK
| | - Jon H Wetton
- Department of Genetics & Genome Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK.
| | - Mark A Jobling
- Department of Genetics & Genome Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK.
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Gorobeyko UV, Sheremetyeva IN, Kazakov DV, Guskov VY. A new type of tandem repeats in Myotis petax (Chiroptera, Vespertilionidae) mitochondrial control region. Mol Biol Rep 2023; 50:5137-5146. [PMID: 37115485 DOI: 10.1007/s11033-023-08468-4] [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: 12/31/2022] [Accepted: 04/18/2023] [Indexed: 04/29/2023]
Abstract
BACKGROUND Tandem repeats in mitochondrial DNA control region are known to different animal taxa, including bat species of the family Vespertilionidae. The long R1-repeats in the bat ETAS-domain are often presented in a variable copy number and may exhibit both inter-individual and intra-individual sequence diversity. The function of repeats in the control region is still unclear, but it has been shown that repetitive sequences in some animal groups (shrews, cats and sheep) may include parts of ETAS1 and ETAS2 conservative blocks of mitochondrial DNA. METHODS AND RESULTS Analysis of the control region sequences for 31 Myotis petax specimens allowed the identification of the inter-individual variability and clarification of the composition of the R1-repeats. The copy number of the R1-repeats varies from 4 to 7 in individuals. The specimens examined do not exhibit a size heteroplasmy previously described for Myotis species. The unusual short 30 bp R1-repeats have been detected in M. petax for the first time. The ten specimens from Amur Region and Primorsky Territory have one or two copies of these additional repeats. CONCLUSIONS It was determined that the R1-repeats in M. petax control region consist of parts of the ETAS1 and ETAS2 blocks. The origin of the additional repeats seems to be related to the 51 bp deletion in the central part of the R1-repeat unit and subsequent duplication. Comparison of repetitive sequences in the control region of closely-related Myotis species identified the occurrence of incomplete repeats also resulting from the short deletions, but distinct from additional repeats of M. petax.
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Affiliation(s)
- Uliana Vasilievna Gorobeyko
- Federal Scientific Center of the East Asia Terrestrial Biodiversity Far Eastern Branch of Russian Academy of Sciences, 159 Prospect Stoletiya St., Vladivostok, 690022, Russia.
| | - Irina Nikolaevna Sheremetyeva
- Federal Scientific Center of the East Asia Terrestrial Biodiversity Far Eastern Branch of Russian Academy of Sciences, 159 Prospect Stoletiya St., Vladivostok, 690022, Russia
| | - Denis Vasilievich Kazakov
- Institute of Environmental and Agricultural Biology (X-BIO), Tyumen State University, 6 Volodarskogo St., Tyumen, 625003, Russia
| | - Valentin Yurievich Guskov
- Federal Scientific Center of the East Asia Terrestrial Biodiversity Far Eastern Branch of Russian Academy of Sciences, 159 Prospect Stoletiya St., Vladivostok, 690022, Russia
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Love Stowell SM, Gagne RB, McWhirter D, Edwards W, Ernest HB. Bighorn Sheep Genetic Structure in Wyoming Reflects Geography and Management. J Wildl Manage 2020. [DOI: 10.1002/jwmg.21882] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Sierra M. Love Stowell
- Wildlife Genomics & Disease Ecology Lab, Department of Veterinary SciencesUniversity of Wyoming 1174 Snowy Range Rd Laramie WY 82070 USA
| | - Roderick B. Gagne
- Wildlife Genomics & Disease Ecology Lab, Department of Veterinary SciencesUniversity of Wyoming 1174 Snowy Range Rd Laramie WY 82070 USA
| | - Doug McWhirter
- Wyoming Game and Fish DepartmentJackson Regional Office 420 N Cache St Jackson WY 830001 USA
| | - William Edwards
- Wyoming Game and Fish DepartmentWildlife Health Laboratory 1174 Snowy Range Rd Laramie WY 82070 USA
| | - Holly B. Ernest
- Wildlife Genomics & Disease Ecology Lab, Department of Veterinary SciencesUniversity of Wyoming 1174 Snowy Range Rd Laramie WY 82070 USA
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Genome-Wide SNP Discovery and Analysis of Genetic Diversity in Farmed Sika Deer ( Cervus nippon) in Northeast China Using Double-Digest Restriction Site-Associated DNA Sequencing. G3-GENES GENOMES GENETICS 2017; 7:3169-3176. [PMID: 28751500 PMCID: PMC5592941 DOI: 10.1534/g3.117.300082] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Sika deer are an economically valuable species owing to their use in traditional Chinese medicine, particularly their velvet antlers. Sika deer in northeast China are mostly farmed in enclosure. Therefore, genetic management of farmed sika deer would benefit from detailed knowledge of their genetic diversity. In this study, we generated over 1.45 billion high-quality paired-end reads (288 Gbp) across 42 unrelated individuals using double-digest restriction site-associated DNA sequencing (ddRAD-seq). A total of 96,188 (29.63%) putative biallelic SNP loci were identified with an average sequencing depth of 23×. Based on the analysis, we found that the majority of the loci had a deficit of heterozygotes (FIS >0) and low values of Hobs, which could be due to inbreeding and Wahlund effects. We also developed a collection of high-quality SNP probes that will likely be useful in a variety of applications in genotyping for cervid species in the future.
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