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Schwartz LC, González VL, Strong EE, Truebano M, Hilbish TJ. Transgressive gene expression and expression plasticity under thermal stress in a stable hybrid zone. Mol Ecol 2024; 33:e17333. [PMID: 38597343 DOI: 10.1111/mec.17333] [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: 06/21/2022] [Revised: 02/21/2024] [Accepted: 03/18/2024] [Indexed: 04/11/2024]
Abstract
Interspecific hybridization can lead to myriad outcomes, including transgressive phenotypes in which the hybrids are more fit than either parent species. Such hybrids may display important traits in the context of climate change, able to respond to novel environmental conditions not previously experienced by the parent populations. While this has been evaluated in an agricultural context, the role of transgressive hybrids under changing conditions in the wild remains largely unexplored; this is especially true regarding transgressive gene expression. Using the blue mussel species complex (genus Mytilus) as a model system, we investigated the effects of hybridization on temperature induced gene expression plasticity by comparing expression profiles in parental species and their hybrids following a 2-week thermal challenge. Hybrid expression plasticity was most often like one parent or the other (50%). However, a large fraction of genes (26%) showed transgressive expression plasticity (i.e. the change in gene expression was either greater or lesser than that of both parent species), while only 2% were intermediately plastic in hybrids. Despite their close phylogenetic relationship, there was limited overlap in the differentially expressed genes responding to temperature, indicating interspecific differences in the responses to high temperature in which responses from hybrids are distinct from both parent species. We also identified differentially expressed long non-coding RNAs (lncRNAs), which we suggest may contribute to species-specific differences in thermal tolerance. Our findings provide important insight into the impact of hybridization on gene expression under warming. We propose transgressive hybrids may play an important role in population persistence under future warming conditions.
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Affiliation(s)
- Lindsey C Schwartz
- Department of Biological Sciences, The University of South Carolina, Columbia, South Carolina, USA
- Department of Invertebrate Zoology, Smithsonian National Museum of Natural History, Washington, District of Columbia, USA
- Department of Biology, University of Louisiana at Lafayette, Lafayette, Louisiana, USA
| | - Vanessa L González
- Informatics and Data Science Center, Smithsonian National Museum of Natural History, Washington, District of Columbia, USA
| | - Ellen E Strong
- Department of Invertebrate Zoology, Smithsonian National Museum of Natural History, Washington, District of Columbia, USA
| | - Manuela Truebano
- Marine Biology and Ecology Research Centre, School of Biological and Marine Sciences, University of Plymouth, Plymouth, UK
| | - Thomas J Hilbish
- Department of Biological Sciences, The University of South Carolina, Columbia, South Carolina, USA
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2
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Manahan DN, Nachman MW. Alternative splicing and environmental adaptation in wild house mice. Heredity (Edinb) 2024; 132:133-141. [PMID: 38012302 PMCID: PMC10923775 DOI: 10.1038/s41437-023-00663-0] [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: 04/30/2023] [Revised: 11/06/2023] [Accepted: 11/07/2023] [Indexed: 11/29/2023] Open
Abstract
A major goal of evolutionary genetics is to understand the genetic and molecular mechanisms underlying adaptation. Previous work has established that changes in gene regulation may contribute to adaptive evolution, but most studies have focused on mRNA abundance and only a few studies have investigated the role of post-transcriptional processing. Here, we use a combination of exome sequences and short-read RNA-Seq data from wild house mice (Mus musculus domesticus) collected along a latitudinal transect in eastern North America to identify candidate genes for local adaptation through alternative splicing. First, we identified alternatively spliced transcripts that differ in frequency between mice from the northern-most and southern-most populations in this transect. We then identified the subset of these transcripts that exhibit clinal patterns of variation among all populations in the transect. Finally, we conducted association studies to identify cis-acting splicing quantitative trait loci (cis-sQTL), and we identified cis-sQTL that overlapped with previously ascertained targets of selection from genome scans. Together, these analyses identified a small set of alternatively spliced transcripts that may underlie environmental adaptation in house mice. Many of these genes have known phenotypes associated with body size, a trait that varies clinally in these populations. We observed no overlap between these genes and genes previously identified by changes in mRNA abundance, indicating that alternative splicing and changes in mRNA abundance may provide separate molecular mechanisms of adaptation.
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Affiliation(s)
- David N Manahan
- Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, CA, 94720, USA.
| | - Michael W Nachman
- Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, CA, 94720, USA
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Innes PA, Goebl AM, Smith CCR, Rosenberger K, Kane NC. Gene expression and alternative splicing contribute to adaptive divergence of ecotypes. Heredity (Edinb) 2024; 132:120-132. [PMID: 38071268 PMCID: PMC10924094 DOI: 10.1038/s41437-023-00665-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 11/23/2023] [Accepted: 11/24/2023] [Indexed: 03/10/2024] Open
Abstract
Regulation of gene expression is a critical link between genotype and phenotype explaining substantial heritable variation within species. However, we are only beginning to understand the ways that specific gene regulatory mechanisms contribute to adaptive divergence of populations. In plants, the post-transcriptional regulatory mechanism of alternative splicing (AS) plays an important role in both development and abiotic stress response, making it a compelling potential target of natural selection. AS allows organisms to generate multiple different transcripts/proteins from a single gene and thus may provide a source of evolutionary novelty. Here, we examine whether variation in alternative splicing and gene expression levels might contribute to adaptation and incipient speciation of dune-adapted prairie sunflowers in Great Sand Dunes National Park, Colorado, USA. We conducted a common garden experiment to assess transcriptomic variation among ecotypes and analyzed differential expression, differential splicing, and gene coexpression. We show that individual genes are strongly differentiated for both transcript level and alternative isoform proportions, even when grown in a common environment, and that gene coexpression networks are disrupted between ecotypes. Furthermore, we examined how genome-wide patterns of sequence divergence correspond to divergence in transcript levels and isoform proportions and find evidence for both cis and trans-regulation. Together, our results emphasize that alternative splicing has been an underappreciated mechanism providing source material for natural selection at short evolutionary time scales.
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Affiliation(s)
- Peter A Innes
- Ecology and Evolutionary Biology Department, University of Colorado, Boulder, CO, USA.
| | - April M Goebl
- Ecology and Evolutionary Biology Department, University of Colorado, Boulder, CO, USA
- Research and Conservation Department, Denver Botanic Gardens, Denver, CO, USA
| | - Chris C R Smith
- Ecology and Evolutionary Biology Department, University of Colorado, Boulder, CO, USA
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA
| | - Kaylee Rosenberger
- Ecology and Evolutionary Biology Department, University of Colorado, Boulder, CO, USA
| | - Nolan C Kane
- Ecology and Evolutionary Biology Department, University of Colorado, Boulder, CO, USA
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Runemark A, Moore EC, Larson EL. Hybridization and gene expression: Beyond differentially expressed genes. Mol Ecol 2024:e17303. [PMID: 38411307 DOI: 10.1111/mec.17303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 02/06/2024] [Accepted: 02/15/2024] [Indexed: 02/28/2024]
Abstract
Gene expression has a key role in reproductive isolation, and studies of hybrid gene expression have identified mechanisms causing hybrid sterility. Here, we review the evidence for altered gene expression following hybridization and outline the mechanisms shown to contribute to altered gene expression in hybrids. Transgressive gene expression, transcending that of both parental species, is pervasive in early generation sterile hybrids, but also frequently observed in viable, fertile hybrids. We highlight studies showing that hybridization can result in transgressive gene expression, also in established hybrid lineages or species. Such extreme patterns of gene expression in stabilized hybrid taxa suggest that altered hybrid gene expression may result in hybridization-derived evolutionary novelty. We also conclude that while patterns of misexpression in hybrids are well documented, the understanding of the mechanisms causing misexpression is lagging. We argue that jointly assessing differences in cell composition and cell-specific changes in gene expression in hybrids, in addition to assessing changes in chromatin and methylation, will significantly advance our understanding of the basis of altered gene expression. Moreover, uncovering to what extent evolution of gene expression results in altered expression for individual genes, or entire networks of genes, will advance our understanding of how selection moulds gene expression. Finally, we argue that jointly studying the dual roles of altered hybrid gene expression, serving both as a mechanism for reproductive isolation and as a substrate for hybrid ecological adaptation, will lead to significant advances in our understanding of the evolution of gene expression.
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Affiliation(s)
- Anna Runemark
- Department of Biology, Lund University, Lund, Sweden
| | - Emily C Moore
- Department of Biological Sciences, University of Denver, Denver, Colorado, USA
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Erica L Larson
- Department of Biological Sciences, University of Denver, Denver, Colorado, USA
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Edgley DE, Carruthers M, Gabagambi NP, Saxon AD, Smith AM, Joyce DA, Vernaz G, Santos ME, Turner GF, Genner MJ. Lateral line system diversification during the early stages of ecological speciation in cichlid fish. BMC Ecol Evol 2024; 24:24. [PMID: 38378480 PMCID: PMC10877828 DOI: 10.1186/s12862-024-02214-5] [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: 09/15/2023] [Accepted: 02/09/2024] [Indexed: 02/22/2024] Open
Abstract
BACKGROUND The mechanosensory lateral line system is an important sensory modality in fishes, informing multiple behaviours related to survival including finding food and navigating in dark environments. Given its ecological importance, we may expect lateral line morphology to be under disruptive selection early in the ecological speciation process. Here we quantify the lateral line system morphology of two ecomorphs of the cichlid fish Astatotilapia calliptera in crater Lake Masoko that have diverged from common ancestry within the past 1,000 years. RESULTS Based on geometric morphometric analyses of CT scans, we show that the zooplanktivorous benthic ecomorph that dominates the deeper waters of the lake has large cranial lateral line canal pores, relative to those of the nearshore invertebrate-feeding littoral ecomorph found in the shallower waters. In contrast, fluorescence imaging revealed no evidence for divergence between ecomorphs in the number of either superficial or canal neuromasts. We illustrate the magnitude of the variation we observe in Lake Masoko A. calliptera in the context of the neighbouring Lake Malawi mega-radiation that comprises over 700 species. CONCLUSIONS These results provide the first evidence of divergence in this often-overlooked sensory modality in the early stages of ecological speciation, suggesting that it may have a role in the broader adaptive radiation process.
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Affiliation(s)
- Duncan E Edgley
- School of Biological Sciences, University of Bristol, Bristol, UK.
| | - Madeleine Carruthers
- School of Biological Sciences, University of Bristol, Bristol, UK
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Nestory P Gabagambi
- Tanzania Fisheries Research Institute, Kyela Centre, P.O. Box 98, Kyela, Mbeya, Tanzania
| | - Andrew D Saxon
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Alan M Smith
- School of Natural Sciences, University of Hull, Hull, UK
| | - Domino A Joyce
- School of Natural Sciences, University of Hull, Hull, UK
| | - Grégoire Vernaz
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, UK
- Wellcome/Cancer Research UK, Gurdon Institute, University of Cambridge, Cambridge, UK
| | - M Emília Santos
- Department of Zoology, University of Cambridge, Cambridge, UK
| | | | - Martin J Genner
- School of Biological Sciences, University of Bristol, Bristol, UK.
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Liu Z, Kishe MA, Gabagambi NP, Shechonge AH, Ngatunga BP, Smith K, Saxon AD, Hudson AG, Linderoth T, Turner GF, Collins RA, Genner MJ. Nuclear environmental DNA resolves fine-scale population genetic structure in an aquatic habitat. iScience 2024; 27:108669. [PMID: 38226161 PMCID: PMC10788193 DOI: 10.1016/j.isci.2023.108669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/13/2023] [Accepted: 12/05/2023] [Indexed: 01/17/2024] Open
Abstract
There is considerable potential for nuclear genomic material in environmental DNA (eDNA) to inform us of population genetic structure within aquatic species. We tested if nuclear allelic composition data sourced from eDNA can resolve fine scale spatial genetic structure of the cichlid fish Astatotilapia calliptera in Lake Masoko, Tanzania. In this ∼35 m deep crater lake the species is diverging into two genetically distinguishable ecomorphs, separated by a thermo-oxycline at ∼15 m that divides biologically distinct water masses. We quantified population genetic structure along a depth transect using single nucleotide polymorphisms (SNPs) derived from genome sequencing of 530 individuals. This population genetic structure was reflected in a focal set of SNPs that were also reliably amplified from eDNA - with allele frequencies derived from eDNA reflecting those of fish within each depth zone. Thus, by targeting known genetic variation between populations within aquatic eDNA, we measured genetic structure within the focal species.
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Affiliation(s)
- Zifang Liu
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS81TQ, UK
| | - Mary A. Kishe
- Tanzania Fisheries Research Institute (TAFIRI), P.O. Box 9750, Dar es Salaam, Tanzania
| | - Nestory P. Gabagambi
- Tanzania Fisheries Research Institute (TAFIRI), P.O. Box 9750, Dar es Salaam, Tanzania
| | - Asilatu H. Shechonge
- Tanzania Fisheries Research Institute (TAFIRI), P.O. Box 9750, Dar es Salaam, Tanzania
| | - Benjamin P. Ngatunga
- Tanzania Fisheries Research Institute (TAFIRI), P.O. Box 9750, Dar es Salaam, Tanzania
| | - Katie Smith
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS81TQ, UK
| | - Andrew D. Saxon
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS81TQ, UK
| | - Alan G. Hudson
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS81TQ, UK
| | - Tyler Linderoth
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
- W.K. Kellogg Biological Station, Michigan State University, Hickory Corners, MI 49060, USA
| | - George F. Turner
- School of Biological Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Rupert A. Collins
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS81TQ, UK
- Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Martin J. Genner
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS81TQ, UK
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Kundu S, De Alwis PS, Kim AR, Lee SR, Kang HE, Go Y, Gietbong FZ, Wibowo A, Kim HW. Mitogenomic Characterization of Cameroonian Endemic Coptodon camerunensis (Cichliformes: Cichlidae) and Matrilineal Phylogeny of Old-World Cichlids. Genes (Basel) 2023; 14:1591. [PMID: 37628642 PMCID: PMC10454717 DOI: 10.3390/genes14081591] [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: 07/19/2023] [Revised: 08/02/2023] [Accepted: 08/04/2023] [Indexed: 08/27/2023] Open
Abstract
The mitogenomic evolution of old-world cichlids is still largely incomplete in Western Africa. In this present study, the complete mitogenome of the Cameroon endemic cichlid, Coptodon camerunensis, was determined by next-generation sequencing. The mitogenome was 16,557 bp long and encoded with 37 genes (13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and a control region). The C. camerunensis mitogenome is AT-biased (52.63%), as exhibited in its congener, Coptodon zillii (52.76% and 53.04%). The majority of PCGs start with an ATG initiation codon, except COI, which starts with a GTG codon and five PCGs and ends with the TAA termination codon and except seven PCGs with an incomplete termination codon. In C. camerunensis mitogenome, most tRNAs showed classical cloverleaf secondary structures, except tRNA-serine with a lack of DHU stem. Comparative analyses of the conserved blocks of two Coptodonini species control regions revealed that the CSB-II block was longer than other blocks and contained highly variable sites. Using 13 concatenated PCGs, the mitogenome-based Bayesian phylogeny easily distinguished all the examined old-world cichlids. Except for Oreochromini and Coptodinini tribe members, the majority of the taxa exhibited monophyletic clustering within their respective lineages. C. camerunensis clustered closely with Heterotilapia buttikoferi (tribe Heterotilapiini) and had paraphyletic clustering with its congener, C. zillii. The Oreochromini species also displayed paraphyletic grouping, and the genus Oreochromis showed a close relationship with Coptodinini and Heterotilapiini species. In addition, illustrating the known distribution patterns of old-world cichlids, the present study is congruent with the previous hypothesis and proclaims that prehistoric geological evolution plays a key role in the hydroclimate of the African continent during Mesozoic, which simultaneously disperses and/or colonizes cichlids in different ichthyological provinces and Rift Lake systems in Africa. The present study suggests that further mitogenomes of cichlid species are required, especially from western Africa, to understand their unique evolution and adaptation.
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Affiliation(s)
- Shantanu Kundu
- Department of Marine Biology, Pukyong National University, Busan 48513, Republic of Korea; (S.K.); (P.S.D.A.)
| | - Piyumi S. De Alwis
- Department of Marine Biology, Pukyong National University, Busan 48513, Republic of Korea; (S.K.); (P.S.D.A.)
| | - Ah Ran Kim
- Marine Integrated Biomedical Technology Center, National Key Research Institutes in Universities, Pukyong National University, Busan 48513, Republic of Korea; (A.R.K.); (S.R.L.)
| | - Soo Rin Lee
- Marine Integrated Biomedical Technology Center, National Key Research Institutes in Universities, Pukyong National University, Busan 48513, Republic of Korea; (A.R.K.); (S.R.L.)
| | - Hye-Eun Kang
- Institute of Marine Life Science, Pukyong National University, Busan 48513, Republic of Korea;
| | - Yunji Go
- Industry 4.0 Convergence Bionics Engineering, Pukyong National University, Busan 48513, Republic of Korea;
| | | | - Arif Wibowo
- Research Center for Conservation of Marine and Inland Water Resources, National Research and Innovation Agency (BRIN), South Tangerang 15314, Indonesia;
| | - Hyun-Woo Kim
- Department of Marine Biology, Pukyong National University, Busan 48513, Republic of Korea; (S.K.); (P.S.D.A.)
- Marine Integrated Biomedical Technology Center, National Key Research Institutes in Universities, Pukyong National University, Busan 48513, Republic of Korea; (A.R.K.); (S.R.L.)
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