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Zhang X, Chen H, Ni Y, Wu B, Li J, Burzyński A, Liu C. Plant mitochondrial genome map (PMGmap): A software tool for the comprehensive visualization of coding, noncoding and genome features of plant mitochondrial genomes. Mol Ecol Resour 2024; 24:e13952. [PMID: 38523350 DOI: 10.1111/1755-0998.13952] [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: 10/18/2023] [Revised: 12/18/2023] [Accepted: 03/08/2024] [Indexed: 03/26/2024]
Abstract
Tools for visualizing genomes are essential for investigating genomic features and their interactions. Currently, tools designed originally for animal mitogenomes and plant plastomes are used to visualize the mitogens of plants but cannot accurately display features specific to plant mitogenomes, such as nonlinear exon arrangement for genes, the prevalence of functional noncoding features and complex chromosomal architecture. To address these problems, a software package, plant mitochondrial genome map (PMGmap), was developed using the Python programming language. PMGmap can draw genes at exon levels; draw cis- and trans-splicing gene maps, noncoding features and repetitive sequences; and scale genic regions by using the scaling of the genic regions on the mitogenome (SAGM) algorithm. It can also draw multiple chromosomes simultaneously. Compared with other state-of-the-art tools, PMGmap showed better performance in visualizing 405 plant mitogenomes, showing potential as an invaluable tool for plant mitogenome research. The web and container versions and the source code of PMGmap can be accessed through the following link: http://www.1kmpg.cn/pmgmap.
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Affiliation(s)
- Xinyi Zhang
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Haimei Chen
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Yang Ni
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Bin Wu
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Jingling Li
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Artur Burzyński
- Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland
| | - Chang Liu
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
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Zhao B, Gao S, Zhao M, Lv H, Song J, Wang H, Zeng Q, Liu J. Mitochondrial genomic analyses provide new insights into the "missing" atp8 and adaptive evolution of Mytilidae. BMC Genomics 2022; 23:738. [PMID: 36324074 PMCID: PMC9628169 DOI: 10.1186/s12864-022-08940-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 10/11/2022] [Indexed: 11/07/2022] Open
Abstract
Background Mytilidae, also known as marine mussels, are widely distributed in the oceans worldwide. Members of Mytilidae show a tremendous range of ecological adaptions, from the species distributed in freshwater to those that inhabit in deep-sea. Mitochondria play an important role in energy metabolism, which might contribute to the adaptation of Mytilidae to different environments. In addition, some bivalve species are thought to lack the mitochondrial protein-coding gene ATP synthase F0 subunit 8. Increasing studies indicated that the absence of atp8 may be caused by annotation difficulties for atp8 gene is characterized by highly divergent, variable length. Results In this study, the complete mitochondrial genomes of three marine mussels (Xenostrobus securis, Bathymodiolus puteoserpentis, Gigantidas vrijenhoeki) were newly assembled, with the lengths of 14,972 bp, 20,482, and 17,786 bp, respectively. We annotated atp8 in the sequences that we assembled and the sequences lacking atp8. The newly annotated atp8 sequences all have one predicted transmembrane domain, a similar hydropathy profile, as well as the C-terminal region with positively charged amino acids. Furthermore, we reconstructed the phylogenetic trees and performed positive selection analysis. The results showed that the deep-sea bathymodiolines experienced more relaxed evolutionary constraints. And signatures of positive selection were detected in nad4 of Limnoperna fortunei, which may contribute to the survival and/or thriving of this species in freshwater. Conclusions Our analysis supported that atp8 may not be missing in the Mytilidae. And our results provided evidence that the mitochondrial genes may contribute to the adaptation of Mytilidae to different environments. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08940-8.
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Affiliation(s)
- Baojun Zhao
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Shengtao Gao
- Key Laboratory of Tropical Aquatic Germplasm of Hainan Province, Sanya Oceanog Inst, Ocean University of China, Sanya, 572000, China
| | - Mingyang Zhao
- Key Laboratory of Tropical Aquatic Germplasm of Hainan Province, Sanya Oceanog Inst, Ocean University of China, Sanya, 572000, China
| | - Hongyu Lv
- Key Laboratory of Tropical Aquatic Germplasm of Hainan Province, Sanya Oceanog Inst, Ocean University of China, Sanya, 572000, China
| | - Jingyu Song
- Key Laboratory of Tropical Aquatic Germplasm of Hainan Province, Sanya Oceanog Inst, Ocean University of China, Sanya, 572000, China
| | - Hao Wang
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Qifan Zeng
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China. .,Key Laboratory of Tropical Aquatic Germplasm of Hainan Province, Sanya Oceanog Inst, Ocean University of China, Sanya, 572000, China. .,Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China.
| | - Jing Liu
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China.
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Lubośny M, Śmietanka B, Lasota R, Burzyński A. Confirmation of the first intronic sequence in the bivalvian mitochondrial genome of Macoma balthica (Linnaeus, 1758). Biol Lett 2022; 18:20220275. [PMID: 36196553 PMCID: PMC9532982 DOI: 10.1098/rsbl.2022.0275] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In 2020, the first male-type mitochondrial genome from the clam Macoma balthica was published. Apart from the unusual doubly uniparental inheritance of mtDNA, scientists observed a unique (over 4k bp long) extension in the middle of the cox2 gene. We have attempted to replicate these data by NGS DNA sequencing and explore further the expression of the long cox2 gene. In our study, we report an even longer cox2 gene (over 5.5 kbp) with no stop codon separating conserved cox2 domains, as well as, based on the rtPCR, a lower relative gene expression pattern of the middle part of the gene (5' = 1; mid = 0.46; 3' = 0.89). Lastly, we sequenced the cox2 gene transcript proving the excision of the intronic sequence.
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Affiliation(s)
- Marek Lubośny
- Department of Genetics and Marine Biotechnology, Institute of Oceanology Polish Academy of Sciences, Sopot 81-712, Poland
| | - Beata Śmietanka
- Department of Genetics and Marine Biotechnology, Institute of Oceanology Polish Academy of Sciences, Sopot 81-712, Poland
| | - Rafał Lasota
- Faculty of Oceanography and Geography, Division of Marine Ecosystems Functioning, University of Gdańsk, Gdynia 81-378, Poland
| | - Artur Burzyński
- Department of Genetics and Marine Biotechnology, Institute of Oceanology Polish Academy of Sciences, Sopot 81-712, Poland
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Cunha RL, Nicastro KR, Zardi GI, Madeira C, McQuaid CD, Cox CJ, Castilho R. Comparative mitogenomic analyses and gene rearrangements reject the alleged polyphyly of a bivalve genus. PeerJ 2022; 10:e13953. [PMID: 36187748 PMCID: PMC9521344 DOI: 10.7717/peerj.13953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 08/05/2022] [Indexed: 01/19/2023] Open
Abstract
Background The order and orientation of genes encoded by animal mitogenomes are typically conserved, although there is increasing evidence of multiple rearrangements among mollusks. The mitogenome from a Brazilian brown mussel (hereafter named B1) classified as Perna perna Linnaeus, 1758 and assembled from Illumina short-length reads revealed an unusual gene order very different from other congeneric species. Previous mitogenomic analyses based on the Brazilian specimen and other Mytilidae suggested the polyphyly of the genus Perna. Methods To confirm the proposed gene rearrangements, we sequenced a second Brazilian P. perna specimen using the "primer-walking" method and performed the assembly using as reference Perna canaliculus. This time-consuming sequencing method is highly effective when assessing gene order because it relies on sequentially-determined, overlapping fragments. We also sequenced the mitogenomes of eastern and southwestern South African P. perna lineages to analyze the existence of putative intraspecific gene order changes as the two lineages show overlapping distributions but do not exhibit a sister relationship. Results The three P. perna mitogenomes sequenced in this study exhibit the same gene order as the reference. CREx, a software that heuristically determines rearrangement scenarios, identified numerous gene order changes between B1 and our P. perna mitogenomes, rejecting the previously proposed gene order for the species. Our results validate the monophyly of the genus Perna and indicate a misidentification of B1.
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Affiliation(s)
- Regina L. Cunha
- Centre of Marine Sciences, CCMAR, University of Algarve, Campus de Gambelas, Faro, Algarve, Portugal
| | - Katy R. Nicastro
- Centre of Marine Sciences, CCMAR, University of Algarve, Campus de Gambelas, Faro, Algarve, Portugal,CNRS, Univ. Littoral Côte d’Opale, UMR 8187 – LOG – Laboratoire d’Océanologie et de Géosciences, Université de Lille, Lille, France,Department of Zoology and Entomology, Rhodes University, Grahamstown, South Africa
| | - Gerardo I. Zardi
- Department of Zoology and Entomology, Rhodes University, Grahamstown, South Africa
| | - Celine Madeira
- Centre of Marine Sciences, CCMAR, University of Algarve, Campus de Gambelas, Faro, Algarve, Portugal
| | | | - Cymon J. Cox
- Centre of Marine Sciences, CCMAR, University of Algarve, Campus de Gambelas, Faro, Algarve, Portugal
| | - Rita Castilho
- Centre of Marine Sciences, CCMAR, University of Algarve, Campus de Gambelas, Faro, Algarve, Portugal
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Lubośny M, Śmietanka B, Arculeo M, Burzyński A. No evidence of DUI in the Mediterranean alien species Brachidontes pharaonis (P. Fisher, 1870) despite mitochondrial heteroplasmy. Sci Rep 2022; 12:8569. [PMID: 35595866 PMCID: PMC9122905 DOI: 10.1038/s41598-022-12606-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 05/13/2022] [Indexed: 01/05/2023] Open
Abstract
Two genetically different mitochondrial haplogroups of Brachidontes pharaonis (p-distance 6.8%) have been identified in the Mediterranean Sea. This hinted at a possible presence of doubly uniparental inheritance in this species. To ascertain this possibility, we sequenced two complete mitogenomes of Brachidontes pharaonis mussels and performed a qPCR analysis to measure the relative mitogenome copy numbers of both mtDNAs. Despite the presence of two very similar regions composed entirely of repetitive sequences in the two haplogroups, no recombination between mitogenomes was detected. In heteroplasmic individuals, both mitogenomes were present in the generative tissues of both sexes, which argues against the presence of doubly uniparental inheritance in this species.
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Affiliation(s)
- Marek Lubośny
- Department of Genetics and Marine Biotechnology, Institute of Oceanology Polish Academy of Sciences, Sopot, Poland.
| | - Beata Śmietanka
- Department of Genetics and Marine Biotechnology, Institute of Oceanology Polish Academy of Sciences, Sopot, Poland
| | - Marco Arculeo
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, Palermo, Italy
| | - Artur Burzyński
- Department of Genetics and Marine Biotechnology, Institute of Oceanology Polish Academy of Sciences, Sopot, Poland
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Mitochondrial Genomes, Phylogenetic Associations, and SNP Recovery for the Key Invasive Ponto-Caspian Amphipods in Europe. Int J Mol Sci 2021; 22:ijms221910300. [PMID: 34638649 PMCID: PMC8509019 DOI: 10.3390/ijms221910300] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 09/18/2021] [Accepted: 09/21/2021] [Indexed: 11/17/2022] Open
Abstract
The Ponto-Caspian region is the main donor of invasive amphipods to freshwater ecosystems, with at least 13 species successfully established in European inland waters. Dikerogammarus spp. and Pontogammarus robustoides are among the most successful, due to their strong invasive impact on local biota. However, genomic knowledge about these invaders is scarce, while phylogeography and population genetics have been based on short fragments of mitochondrial markers or nuclear microsatellites. In this study, we provide: (i) a reconstruction of six mitogenomes for four invasive gammarids (D. villosus, D. haemobaphes, D. bispinosus, and P. robustoides); (ii) a comparison between the structure of the newly obtained mitogenomes and those from the literature; (iii) SNP calling rates for individual D. villosus and D. haemobaphes from different invasion sites across Europe; and (iv) the first time-calibrated full mitogenome phylogeny reconstruction of several Ponto-Caspian taxa. We found that, in comparison to other gammarids, the mitogenomes of Ponto-Caspian species show a translocation between the tRNA-E and tRNA-R positions. Phylogenetic reconstruction using the mitogenomes identified that Ponto-Caspian gammarids form a well-supported group that originated in the Miocene. Our study supports paraphyly in the family Gammaridae. These provided mitogenomes will serve as vital genetic resources for the development of new markers for PCR-based identification methods and demographic studies.
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Dégletagne C, Abele D, Glöckner G, Alric B, Gruber H, Held C. Presence of male mitochondria in somatic tissues and their functional importance at the whole animal level in the marine bivalve Arctica islandica. Commun Biol 2021; 4:1104. [PMID: 34545198 PMCID: PMC8452683 DOI: 10.1038/s42003-021-02593-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 08/16/2021] [Indexed: 02/08/2023] Open
Abstract
Metazoans normally possess a single lineage of mitochondria inherited from the mother (♀-type mitochondria) while paternal mitochondria are absent or eliminated in fertilized eggs. In doubly uniparental inheritance (DUI), which is specific to the bivalve clade including the ocean quahog, Arctica islandica, ♂-type mitochondria are retained in male gonads and, in a few species, small proportions of ♂-type mitochondria co-exist with ♀-type in somatic tissues. To the best of our knowledge, we report, for the first time in metazoan, the natural occurrence of male and female individuals with exclusively ♂-type mitochondria in somatic tissues of the bivalve A. islandica. Mitochondrial genomes differ by ~5.5% at DNA sequence level. Exclusive presence of ♂-type mitochondria affects mitochondrial complexes partially encoded by mitochondrial genes and leads to a sharp drop in respiratory capacity. Through a combination of whole mitochondrial genome sequencing and molecular assays (gene presence and expression), we demonstrate that 1) 11% of individuals of an Icelandic population appear homoplasmic for ♂-type mitochondria in somatic tissues, 2) ♂-type mitochondrial genes are transcribed and 3) individuals with ♂-type mitochondria in somatic cells lose 30% of their wild-type respiratory capacity. This mitochondrial pattern in A. islandica is a special case of DUI, highlighted in individuals from both sexes with functional consequences at cellular and conceivably whole animal level.
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Affiliation(s)
- Cyril Dégletagne
- grid.10894.340000 0001 1033 7684Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany ,grid.7849.20000 0001 2150 7757Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR5023 LEHNA, Villeurbanne, France
| | - Doris Abele
- grid.10894.340000 0001 1033 7684Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany
| | - Gernot Glöckner
- grid.6190.e0000 0000 8580 3777Institute for Biochemistry I, Medical Faculty, University of Cologne, Cologne, Germany
| | - Benjamin Alric
- grid.7849.20000 0001 2150 7757Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR5023 LEHNA, Villeurbanne, France
| | - Heike Gruber
- grid.419520.b0000 0001 2222 4708Max Planck Institute for Evolutionary Biology, Department of Evolutionary Theory, Plön, Germany
| | - Christoph Held
- grid.10894.340000 0001 1033 7684Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany
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Pons J, Ensenyat JJ, Bover P, Serra M, Nardi F. Aln2tbl: building a mitochondrial features table from a assembly alignment in fasta format. MITOCHONDRIAL DNA PART B-RESOURCES 2021; 6:2732-2735. [PMID: 34447886 PMCID: PMC8386716 DOI: 10.1080/23802359.2021.1966334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The sequencing, annotation and analysis of complete mitochondrial genomes is an important research tool in phylogeny and evolution. Starting with the primary sequence, genes/features are generally annotated automatically to obtain preliminary annotations in the form of a feature table. Further manual curation in a graphic alignment editor is nevertheless necessary to revise annotations. As such, the automatically generated feature table is invalidated and has to be modified manually before submission to data banks. We developed aln2tbl.py, a python script that recreates a feature table from a manually refined alignment of genes mapped on the mitochondrial genome in fasta format. The feature table is populated with notes and annotations specific to mitochondrial genomes. The table can be used to create a sqn file to be submitted directly to data banks. In summary, our scripts fills one gap in the available toolbox and, combined with other software, allows the automation of the entire process, from primary sequence to annotated genome submission, even if a manual curation step is conducted in a visual sequence editor.
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Affiliation(s)
- Joan Pons
- Departament de Biodiversitat Animal i Microbiana, Institut Mediterrani d'Estudis Avançats (IMEDEA, CSIC-UIB), Esporles, Spain
| | - Juan José Ensenyat
- Tecnologies de la informació i la comunicació, Institut Mediterrani d'Estudis Avançats (IMEDEA, CSIC-UIB), Esporles, Spain
| | - Pere Bover
- Instituto Universitario de Investigación en Ciencias Ambientales (IUCA), Grupo Aragosaurus - Departamento de Ciencias de la Tierra, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain
| | - Miquel Serra
- Tecnologies de la informació i la comunicació, Institut Mediterrani d'Estudis Avançats (IMEDEA, CSIC-UIB), Esporles, Spain
| | - Francesco Nardi
- Department of Life Sciences, University of Siena, Siena, Italy
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Stewart DT, Robicheau BM, Youssef N, Garrido-Ramos MA, Chase EE, Breton S. Expanding the Search for Sperm Transmission Elements in the Mitochondrial Genomes of Bivalve Mollusks. Genes (Basel) 2021; 12:1211. [PMID: 34440385 PMCID: PMC8394068 DOI: 10.3390/genes12081211] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/30/2021] [Accepted: 08/03/2021] [Indexed: 11/16/2022] Open
Abstract
Doubly uniparental inheritance (DUI) of mitochondrial DNA (mtDNA) in bivalve mollusks is one of the most notable departures from the paradigm of strict maternal inheritance of mtDNA among metazoans. Recently, work on the Mediterranean mussel Mytilus galloprovincialis suggested that a nucleotide motif in the control region of this species, known as the sperm transmission element (STE), helps protect male-transmitted mitochondria from destruction during spermatogenesis. Subsequent studies found similar, yet divergent, STE motifs in other marine mussels. Here, we extend the in silico search for mtDNA signatures resembling known STEs. This search is carried out for the large unassigned regions of 157 complete mitochondrial genomes from within the Mytiloida, Veneroida, Unionoida, and Ostreoida bivalve orders. Based on a sliding window approach, we present evidence that there are additional putative STE signatures in the large unassigned regions of several marine clams and freshwater mussels with DUI. We discuss the implications of this finding for interpreting the origin of doubly uniparental inheritance in ancestral bivalve mollusks, as well as potential future in vitro and in silico studies that could further refine our understanding of the early evolution of this unusual system of mtDNA inheritance.
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Affiliation(s)
- Donald T. Stewart
- Department of Biology, Acadia University, Wolfville, NS B4P 2R6, Canada
| | - Brent M. Robicheau
- Department of Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada; (B.M.R.); (N.Y.)
| | - Noor Youssef
- Department of Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada; (B.M.R.); (N.Y.)
| | - Manuel A. Garrido-Ramos
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain;
| | - Emily E. Chase
- Institut Méditerranéen d’Océanologie, Aix-Marseille University, 13288 Marseille, France;
- Institut Hospitalo-Universitaire (IHU) Méditerranée Infection, 19-21 Boulevard Jean Moulin, 13005 Marseille, France
| | - Sophie Breton
- Département de Sciences Biologiques, Université de Montréal, Montréal, QC H3C 3J7, Canada;
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Stewart DT, Stephenson CM, Stanton LM, Chase EE, Robicheau BM, Hoeh WR, Breton S. A proposed method for analyzing molecular signatures to detect hermaphroditism in freshwater mussels: a case study using the eastern floater (Pyganodon cataracta). CAN J ZOOL 2021. [DOI: 10.1139/cjz-2020-0166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Many freshwater mussels (order Unionida) have an unusual system of doubly uniparental inheritance (DUI) of mitochondrial (mt) DNA. In species with DUI, males possess a female-transmitted (F-type) mt genome and a male-transmitted (M-type) mt genome. These genomes contain non-canonical open reading frame (orf) genes, referred to as f-orf and m-orf, present in F and M mt genomes, respectively. These genes have been implicated in sexual development in Unionida. When gonochoric species become hermaphroditic, which has happened several times in Unionida, they lose their M-type mt genome and f-orf genes evolve dramatically. Resulting F-ORF proteins are highly divergent in terms of primary nucleotide sequence, inferred amino acids, and hydrophobic properties; these genes (and proteins) are referred to as hermaphroditic orfs or h-orfs (and H-ORFs). We investigated patterns of hydrophobicity divergence for H-ORF proteins in hermaphrodites versus F-ORF proteins in closely related gonochoric species against cytochrome c oxidase subunit 1 (cox1) divergences. This approach was used to assess whether cryptic hermaphrodites can be detected. Although we did not detect evidence for the recent transition of any populations of eastern floaters (Pyganodon cataracta (Say, 1817)) to hermaphroditism, our analyses demonstrate that molecular signatures in mtDNA can be used to detect hermaphroditism in freshwater mussels.
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Affiliation(s)
- Donald T. Stewart
- Department of Biology, Acadia University, Wolfville, NS B4P 2R6, Canada
| | | | | | - Emily E. Chase
- Department of Biology, Acadia University, Wolfville, NS B4P 2R6, Canada
| | | | - W. Randolph Hoeh
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Sophie Breton
- Département de sciences biologiques, Université de Montréal, QC H2V 0B3, Canada
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