1
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Schield DR, Perry BW, Adams RH, Holding ML, Nikolakis ZL, Gopalan SS, Smith CF, Parker JM, Meik JM, DeGiorgio M, Mackessy SP, Castoe TA. The roles of balancing selection and recombination in the evolution of rattlesnake venom. Nat Ecol Evol 2022; 6:1367-1380. [PMID: 35851850 PMCID: PMC9888523 DOI: 10.1038/s41559-022-01829-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 06/15/2022] [Indexed: 02/02/2023]
Abstract
The origin of snake venom involved duplication and recruitment of non-venom genes into venom systems. Several studies have predicted that directional positive selection has governed this process. Venom composition varies substantially across snake species and venom phenotypes are locally adapted to prey, leading to coevolutionary interactions between predator and prey. Venom origins and contemporary snake venom evolution may therefore be driven by fundamentally different selection regimes, yet investigations of population-level patterns of selection have been limited. Here, we use whole-genome data from 68 rattlesnakes to test hypotheses about the factors that drive genomic diversity and differentiation in major venom gene regions. We show that selection has resulted in long-term maintenance of genetic diversity within and between species in multiple venom gene families. Our findings are inconsistent with a dominant role of directional positive selection and instead support a role of long-term balancing selection in shaping venom evolution. We also detect rapid decay of linkage disequilibrium due to high recombination rates in venom regions, suggesting that venom genes have reduced selective interference with nearby loci, including other venom paralogues. Our results provide an example of long-term balancing selection that drives trans-species polymorphism and help to explain how snake venom keeps pace with prey resistance.
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Affiliation(s)
- Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA.
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA.
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
- School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Richard H Adams
- Department of Biological and Environmental Sciences, Georgia College and State University, Milledgeville, GA, USA
| | | | | | | | - Cara F Smith
- School of Biological Sciences, University of Northern Colorado, Greeley, CO, USA
| | - Joshua M Parker
- Life Science Department, Fresno City College, Fresno, CA, USA
| | - Jesse M Meik
- Department of Biological Sciences, Tarleton State University, Stephenville, TX, USA
| | - Michael DeGiorgio
- Department of Electrical Engineering and Computer Science, Florida Atlantic University, Boca Raton, FL, USA
| | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, Greeley, CO, USA
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA.
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2
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Solving the microheterogeneity of Bothrops asper myotoxin-II by high-resolution mass spectrometry: Insights into C-terminal region variability in Lys49-phospholipase A2 homologs. Toxicon 2022; 210:123-131. [DOI: 10.1016/j.toxicon.2022.02.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 02/27/2022] [Accepted: 02/28/2022] [Indexed: 11/21/2022]
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3
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Galbraith JD, Ludington AJ, Sanders KL, Amos TG, Thomson VA, Enosi Tuipulotu D, Dunstan N, Edwards RJ, Suh A, Adelson DL. Horizontal Transposon Transfer and Its Implications for the Ancestral Ecology of Hydrophiine Snakes. Genes (Basel) 2022; 13:genes13020217. [PMID: 35205262 PMCID: PMC8872380 DOI: 10.3390/genes13020217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 01/23/2022] [Accepted: 01/23/2022] [Indexed: 02/04/2023] Open
Abstract
Transposable elements (TEs), also known as jumping genes, are sequences able to move or copy themselves within a genome. As TEs move throughout genomes they often act as a source of genetic novelty, hence understanding TE evolution within lineages may help in understanding environmental adaptation. Studies into the TE content of lineages of mammals such as bats have uncovered horizontal transposon transfer (HTT) into these lineages, with squamates often also containing the same TEs. Despite the repeated finding of HTT into squamates, little comparative research has examined the evolution of TEs within squamates. Here we examine a diverse family of Australo-Melanesian snakes (Hydrophiinae) to examine if the previously identified, order-wide pattern of variable TE content and activity holds true on a smaller scale. Hydrophiinae diverged from Asian elapids ~30 Mya and have since rapidly diversified into six amphibious, ~60 marine and ~100 terrestrial species that fill a broad range of ecological niches. We find TE diversity and expansion differs between hydrophiines and their Asian relatives and identify multiple HTTs into Hydrophiinae, including three likely transferred into the ancestral hydrophiine from fish. These HTT events provide the first tangible evidence that Hydrophiinae reached Australia from Asia via a marine route.
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Affiliation(s)
- James D. Galbraith
- School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia; (J.D.G.); (A.J.L.); (K.L.S.); (V.A.T.)
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK
| | - Alastair J. Ludington
- School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia; (J.D.G.); (A.J.L.); (K.L.S.); (V.A.T.)
| | - Kate L. Sanders
- School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia; (J.D.G.); (A.J.L.); (K.L.S.); (V.A.T.)
| | - Timothy G. Amos
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia; (T.G.A.); (D.E.T.)
- Garvan Institute of Medical Research, Sydney, NSW 2010, Australia
| | - Vicki A. Thomson
- School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia; (J.D.G.); (A.J.L.); (K.L.S.); (V.A.T.)
| | - Daniel Enosi Tuipulotu
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia; (T.G.A.); (D.E.T.)
- Division of Immunity, Inflammation and Infection, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2601, Australia
| | | | - Richard J. Edwards
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia; (T.G.A.); (D.E.T.)
- Correspondence: (R.J.E.); (A.S.); (D.L.A.)
| | - Alexander Suh
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TU, UK
- Department of Organismal Biology-Systematic Biology, Evolutionary Biology Centre, Uppsala University, SE-752 36 Uppsala, Sweden
- Correspondence: (R.J.E.); (A.S.); (D.L.A.)
| | - David L. Adelson
- School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia; (J.D.G.); (A.J.L.); (K.L.S.); (V.A.T.)
- South Australian Museum, Adelaide, SA 5000, Australia
- Correspondence: (R.J.E.); (A.S.); (D.L.A.)
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4
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Luo J, Ding Y, Peng Z, Chen K, Zhang X, Xiao T, Chen J. Molecular diversity and evolutionary trends of cysteine-rich peptides from the venom glands of Chinese spider Heteropoda venatoria. Sci Rep 2021; 11:3211. [PMID: 33547373 PMCID: PMC7865051 DOI: 10.1038/s41598-021-82668-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 01/20/2021] [Indexed: 11/14/2022] Open
Abstract
Heteropoda venatoria in the family Sparassidae is highly valued in pantropical countries because the species feed on domestic insect pests. Unlike most other species of Araneomorphae, H. venatoria uses the great speed and strong chelicerae (mouthparts) with toxin glands to capture the insects instead of its web. Therefore, H. venatoria provides unique opportunities for venom evolution research. The venom of H. venatoria was explored by matrix-assisted laser desorption/ionization tandem time-of-flight and analyzing expressed sequence tags. The 154 sequences coding cysteine-rich peptides (CRPs) revealed 24 families based on the phylogenetic analyses of precursors and cysteine frameworks in the putative mature regions. Intriguingly, four kinds of motifs are first described in spider venom. Furthermore, combining the diverse CRPs of H. venatoria with previous spider venom peptidomics data, the structures of precursors and the patterns of cysteine frameworks were analyzed. This work revealed the dynamic evolutionary trends of venom CRPs in H. venatoria: the precursor has evolved an extended mature peptide with more cysteines, and a diminished or even vanished propeptides between the signal and mature peptides; and the CRPs evolved by multiple duplications of an ancestral ICK gene as well as recruitments of non-toxin genes.
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Affiliation(s)
- Jie Luo
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, People's Republic of China
| | - Yiying Ding
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, People's Republic of China
| | - Zhihao Peng
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, People's Republic of China
| | - Kezhi Chen
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, People's Republic of China
| | - Xuewen Zhang
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, People's Republic of China
| | - Tiaoyi Xiao
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, 410128, People's Republic of China
| | - Jinjun Chen
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, People's Republic of China. .,Hunan Provincial Engineering Technology Research Center for Cell Mechanics and Function Analysis, Changsha, 410128, People's Republic of China.
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5
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Alternative mRNA Splicing in Three Venom Families Underlying a Possible Production of Divergent Venom Proteins of the Habu Snake, Protobothrops flavoviridis. Toxins (Basel) 2019; 11:toxins11100581. [PMID: 31600994 PMCID: PMC6832531 DOI: 10.3390/toxins11100581] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/02/2019] [Accepted: 10/05/2019] [Indexed: 11/16/2022] Open
Abstract
Snake venoms are complex mixtures of toxic proteins encoded by various gene families that function synergistically to incapacitate prey. A huge repertoire of snake venom genes and proteins have been reported, and alternative splicing is suggested to be involved in the production of divergent gene transcripts. However, a genome-wide survey of the transcript repertoire and the extent of alternative splicing still remains to be determined. In this study, the comprehensive analysis of transcriptomes in the venom gland was achieved by using PacBio sequencing. Extensive alternative splicing was observed in three venom protein gene families, metalloproteinase (MP), serine protease (SP), and vascular endothelial growth factors (VEGF). Eleven MP and SP genes and a VEGF gene are expressed as a total of 81, 61, and 8 transcript variants, respectively. In the MP gene family, individual genes are transcribed into different classes of MPs by alternative splicing. We also observed trans-splicing among the clustered SP genes. No other venom genes as well as non-venom counterpart genes exhibited alternative splicing. Our results thus indicate a potential contribution of mRNA alternative and trans-splicing in the production of highly variable transcripts of venom genes in the habu snake.
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6
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Unique structure (construction and configuration) and evolution of the array of small serum protein genes of Protobothrops flavoviridis snake. Biosci Rep 2019; 39:BSR20190560. [PMID: 31213576 PMCID: PMC6609765 DOI: 10.1042/bsr20190560] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 06/06/2019] [Accepted: 06/17/2019] [Indexed: 11/27/2022] Open
Abstract
The nucleotide sequence of Protobothrops flavoviridis (Pf) 30534 bp genome segment which contains genes encoding small serum proteins (SSPs) was deciphered. The genome segment contained five SSP genes (PfSSPs), PfSSP-4, PfSSP-5, PfSSP-1, PfSSP-2, and PfSSP-3 in this order and had characteristic configuration and constructions of the particular nucleotide sequences inserted. Comparison between the configurations of the inserted chicken repeat-1 (CR1) fragments of P. flavoviridis and Ophiophagus hannah (Oh) showed that the nucleotide segment encompassing from PfSSP-1 to PfSSP-2 was inverted. The inactive form of PfSSP-1, named PfSSP-1δ(Ψ), found in the intergenic region (I-Reg) between PfSSP-5 and PfSSP-1 had also been destroyed by insertions of the plural long interspersed nuclear elements (LINEs) and DNA transposons. The L2 LINE inserted into the third intron or the particular repetitive sequences inserted into the second intron structurally divided five PfSSPs into two subgroups, the Long SSP subgroup of PfSSP-1, PfSSP-2 and PfSSP-5 or the Short SSP subgroup of PfSSP-3 and PfSSP-4. The mathematical analysis also showed that PfSSPs of the Long SSP subgroup evolved alternately in an accelerated and neutral manner, whereas those of the Short SSP subgroup evolved in an accelerated manner. Moreover, the ortholog analysis of SSPs of various snakes showed that the evolutionary emerging order of SSPs was as follows: SSP-5, SSP-4, SSP-2, SSP-1, and SSP-3. The unique interpretation about accelerated evolution and the novel idea that the transposable elements such as LINEs and DNA transposons are involved in maintaining the host genome besides its own transposition natures were proposed.
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7
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Schield DR, Card DC, Hales NR, Perry BW, Pasquesi GM, Blackmon H, Adams RH, Corbin AB, Smith CF, Ramesh B, Demuth JP, Betrán E, Tollis M, Meik JM, Mackessy SP, Castoe TA. The origins and evolution of chromosomes, dosage compensation, and mechanisms underlying venom regulation in snakes. Genome Res 2019; 29:590-601. [PMID: 30898880 PMCID: PMC6442385 DOI: 10.1101/gr.240952.118] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 02/15/2019] [Indexed: 01/28/2023]
Abstract
Here we use a chromosome-level genome assembly of a prairie rattlesnake (Crotalus viridis), together with Hi-C, RNA-seq, and whole-genome resequencing data, to study key features of genome biology and evolution in reptiles. We identify the rattlesnake Z Chromosome, including the recombining pseudoautosomal region, and find evidence for partial dosage compensation driven by an evolutionary accumulation of a female-biased up-regulation mechanism. Comparative analyses with other amniotes provide new insight into the origins, structure, and function of reptile microchromosomes, which we demonstrate have markedly different structure and function compared to macrochromosomes. Snake microchromosomes are also enriched for venom genes, which we show have evolved through multiple tandem duplication events in multiple gene families. By overlaying chromatin structure information and gene expression data, we find evidence for venom gene-specific chromatin contact domains and identify how chromatin structure guides precise expression of multiple venom gene families. Further, we find evidence for venom gland-specific transcription factor activity and characterize a complement of mechanisms underlying venom production and regulation. Our findings reveal novel and fundamental features of reptile genome biology, provide insight into the regulation of snake venom, and broadly highlight the biological insight enabled by chromosome-level genome assemblies.
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Affiliation(s)
- Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Daren C Card
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Nicole R Hales
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Giulia M Pasquesi
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Heath Blackmon
- Department of Biology, Texas A&M University, College Station, Texas 77843, USA
| | - Richard H Adams
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Andrew B Corbin
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Cara F Smith
- School of Biological Sciences, University of Northern Colorado, Greeley, Colorado 80639, USA
| | - Balan Ramesh
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Jeffery P Demuth
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Esther Betrán
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Marc Tollis
- School of Life Sciences, Arizona State University, Tempe, Arizona 85287, USA
| | - Jesse M Meik
- Department of Biological Sciences, Tarleton State University, Stephenville, Texas 76402, USA
| | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, Greeley, Colorado 80639, USA
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
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8
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The habu genome reveals accelerated evolution of venom protein genes. Sci Rep 2018; 8:11300. [PMID: 30050104 PMCID: PMC6062510 DOI: 10.1038/s41598-018-28749-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 06/29/2018] [Indexed: 01/11/2023] Open
Abstract
Evolution of novel traits is a challenging subject in biological research. Several snake lineages developed elaborate venom systems to deliver complex protein mixtures for prey capture. To understand mechanisms involved in snake venom evolution, we decoded here the ~1.4-Gb genome of a habu, Protobothrops flavoviridis. We identified 60 snake venom protein genes (SV) and 224 non-venom paralogs (NV), belonging to 18 gene families. Molecular phylogeny reveals early divergence of SV and NV genes, suggesting that one of the four copies generated through two rounds of whole-genome duplication was modified for use as a toxin. Among them, both SV and NV genes in four major components were extensively duplicated after their diversification, but accelerated evolution is evident exclusively in the SV genes. Both venom-related SV and NV genes are significantly enriched in microchromosomes. The present study thus provides a genetic background for evolution of snake venom composition.
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9
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Pasquesi GIM, Adams RH, Card DC, Schield DR, Corbin AB, Perry BW, Reyes-Velasco J, Ruggiero RP, Vandewege MW, Shortt JA, Castoe TA. Squamate reptiles challenge paradigms of genomic repeat element evolution set by birds and mammals. Nat Commun 2018; 9:2774. [PMID: 30018307 PMCID: PMC6050309 DOI: 10.1038/s41467-018-05279-1] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 06/25/2018] [Indexed: 12/14/2022] Open
Abstract
Broad paradigms of vertebrate genomic repeat element evolution have been largely shaped by analyses of mammalian and avian genomes. Here, based on analyses of genomes sequenced from over 60 squamate reptiles (lizards and snakes), we show that patterns of genomic repeat landscape evolution in squamates challenge such paradigms. Despite low variance in genome size, squamate genomes exhibit surprisingly high variation among species in abundance (ca. 25–73% of the genome) and composition of identifiable repeat elements. We also demonstrate that snake genomes have experienced microsatellite seeding by transposable elements at a scale unparalleled among eukaryotes, leading to some snake genomes containing the highest microsatellite content of any known eukaryote. Our analyses of transposable element evolution across squamates also suggest that lineage-specific variation in mechanisms of transposable element activity and silencing, rather than variation in species-specific demography, may play a dominant role in driving variation in repeat element landscapes across squamate phylogeny. Large-scale patterns of genomic repeat element evolution have been studied mainly in birds and mammals. Here, the authors analyze the genomes of over 60 squamate reptiles and show high variation in repeat elements compared to mammals and birds, and particularly high microsatellite seeding in snakes.
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Affiliation(s)
- Giulia I M Pasquesi
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Richard H Adams
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Daren C Card
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Drew R Schield
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Andrew B Corbin
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Jacobo Reyes-Velasco
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA.,Department of Biology, New York University Abu Dhabi, Saadiyat Island, United Arab Emirates
| | - Robert P Ruggiero
- Department of Biology, New York University Abu Dhabi, Saadiyat Island, United Arab Emirates
| | - Michael W Vandewege
- Department of Biology, Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA, 19122, USA
| | - Jonathan A Shortt
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA.
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10
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Aird SD, Arora J, Barua A, Qiu L, Terada K, Mikheyev AS. Population Genomic Analysis of a Pitviper Reveals Microevolutionary Forces Underlying Venom Chemistry. Genome Biol Evol 2018; 9:2640-2649. [PMID: 29048530 PMCID: PMC5737360 DOI: 10.1093/gbe/evx199] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2017] [Indexed: 12/24/2022] Open
Abstract
Venoms are among the most biologically active secretions known, and are commonly believed to evolve under extreme positive selection. Many venom gene families, however, have undergone duplication, and are often deployed in doses vastly exceeding the LD50 for most prey species, which should reduce the strength of positive selection. Here, we contrast these selective regimes using snake venoms, which consist of rapidly evolving protein formulations. Though decades of extensive studies have found that snake venom proteins are subject to strong positive selection, the greater action of drift has been hypothesized, but never tested. Using a combination of de novo genome sequencing, population genomics, transcriptomics, and proteomics, we compare the two modes of evolution in the pitviper, Protobothrops mucrosquamatus. By partitioning selective constraints and adaptive evolution in a McDonald–Kreitman-type framework, we find support for both hypotheses: venom proteins indeed experience both stronger positive selection, and lower selective constraint than other genes in the genome. Furthermore, the strength of selection may be modulated by expression level, with more abundant proteins experiencing weaker selective constraint, leading to the accumulation of more deleterious mutations. These findings show that snake venoms evolve by a combination of adaptive and neutral mechanisms, both of which explain their extraordinarily high rates of molecular evolution. In addition to positive selection, which optimizes efficacy of the venom in the short term, relaxed selective constraints for deleterious mutations can lead to more rapid turnover of individual proteins, and potentially to exploration of a larger venom phenotypic space.
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Affiliation(s)
- Steven D Aird
- Ecology and Evolution Unit, Okinawa Institute of Science and Technology Graduate University, Kunigami-gun, Okinawa-ken, Japan
| | - Jigyasa Arora
- Ecology and Evolution Unit, Okinawa Institute of Science and Technology Graduate University, Kunigami-gun, Okinawa-ken, Japan
| | - Agneesh Barua
- Ecology and Evolution Unit, Okinawa Institute of Science and Technology Graduate University, Kunigami-gun, Okinawa-ken, Japan
| | - Lijun Qiu
- Ecology and Evolution Unit, Okinawa Institute of Science and Technology Graduate University, Kunigami-gun, Okinawa-ken, Japan
| | - Kouki Terada
- Okinawa Prefectural Institute of Health and the Environment, Biology and Ecology Group, Nanjo-shi, Okinawa, Japan
| | - Alexander S Mikheyev
- Ecology and Evolution Unit, Okinawa Institute of Science and Technology Graduate University, Kunigami-gun, Okinawa-ken, Japan
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11
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Mutation, Duplication, and More in the Evolution of Venomous Animals and Their Toxins. EVOLUTION OF VENOMOUS ANIMALS AND THEIR TOXINS 2017. [DOI: 10.1007/978-94-007-6458-3_5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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12
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Ortiz JF, Rokas A. CTDGFinder: A Novel Homology-Based Algorithm for Identifying Closely Spaced Clusters of Tandemly Duplicated Genes. Mol Biol Evol 2016; 34:215-229. [DOI: 10.1093/molbev/msw227] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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13
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Dowell NL, Giorgianni MW, Kassner VA, Selegue JE, Sanchez EE, Carroll SB. The Deep Origin and Recent Loss of Venom Toxin Genes in Rattlesnakes. Curr Biol 2016; 26:2434-2445. [PMID: 27641771 DOI: 10.1016/j.cub.2016.07.038] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 07/01/2016] [Accepted: 07/15/2016] [Indexed: 11/26/2022]
Abstract
The genetic origin of novel traits is a central but challenging puzzle in evolutionary biology. Among snakes, phospholipase A2 (PLA2)-related toxins have evolved in different lineages to function as potent neurotoxins, myotoxins, or hemotoxins. Here, we traced the genomic origin and evolution of PLA2 toxins by examining PLA2 gene number, organization, and expression in both neurotoxic and non-neurotoxic rattlesnakes. We found that even though most North American rattlesnakes do not produce neurotoxins, the genes of a specialized heterodimeric neurotoxin predate the origin of rattlesnakes and were present in their last common ancestor (∼22 mya). The neurotoxin genes were then deleted independently in the lineages leading to the Western Diamondback (Crotalus atrox) and Eastern Diamondback (C. adamanteus) rattlesnakes (∼6 mya), while a PLA2 myotoxin gene retained in C. atrox was deleted from the neurotoxic Mojave rattlesnake (C. scutulatus; ∼4 mya). The rapid evolution of PLA2 gene number appears to be due to transposon invasion that provided a template for non-allelic homologous recombination.
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Affiliation(s)
- Noah L Dowell
- Howard Hughes Medical Institute and Laboratory of Molecular Biology, University of Wisconsin-Madison, 1525 Linden Drive, Madison, WI 53706, USA.
| | - Matt W Giorgianni
- Howard Hughes Medical Institute and Laboratory of Molecular Biology, University of Wisconsin-Madison, 1525 Linden Drive, Madison, WI 53706, USA
| | - Victoria A Kassner
- Howard Hughes Medical Institute and Laboratory of Molecular Biology, University of Wisconsin-Madison, 1525 Linden Drive, Madison, WI 53706, USA
| | - Jane E Selegue
- Howard Hughes Medical Institute and Laboratory of Molecular Biology, University of Wisconsin-Madison, 1525 Linden Drive, Madison, WI 53706, USA
| | - Elda E Sanchez
- National Natural Toxins Research Center and Department of Chemistry, Texas A&M University-Kingsville, MSC 224, Kingsville, TX 78363, USA
| | - Sean B Carroll
- Howard Hughes Medical Institute and Laboratory of Molecular Biology, University of Wisconsin-Madison, 1525 Linden Drive, Madison, WI 53706, USA.
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14
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Insights into the Evolution of a Snake Venom Multi-Gene Family from the Genomic Organization of Echis ocellatus SVMP Genes. Toxins (Basel) 2016; 8:toxins8070216. [PMID: 27420095 PMCID: PMC4963849 DOI: 10.3390/toxins8070216] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Revised: 06/29/2016] [Accepted: 07/06/2016] [Indexed: 02/04/2023] Open
Abstract
The molecular events underlying the evolution of the Snake Venom Metalloproteinase (SVMP) family from an A Disintegrin And Metalloproteinase (ADAM) ancestor remain poorly understood. Comparative genomics may provide decisive information to reconstruct the evolutionary history of this multi-locus toxin family. Here, we report the genomic organization of Echis ocellatus genes encoding SVMPs from the PII and PI classes. Comparisons between them and between these genes and the genomic structures of Anolis carolinensis ADAM28 and E. ocellatus PIII-SVMP EOC00089 suggest that insertions and deletions of intronic regions played key roles along the evolutionary pathway that shaped the current diversity within the multi-locus SVMP gene family. In particular, our data suggest that emergence of EOC00028-like PI-SVMP from an ancestral PII(e/d)-type SVMP involved splicing site mutations that abolished both the 3′ splice AG acceptor site of intron 12* and the 5′ splice GT donor site of intron 13*, and resulted in the intronization of exon 13* and the consequent destruction of the structural integrity of the PII-SVMP characteristic disintegrin domain.
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Mezzasalma M, Visone V, Petraccioli A, Odierna G, Capriglione T, Guarino FM. Non-random accumulation of LINE1-like sequences on differentiated snake W chromosomes. J Zool (1987) 2016. [DOI: 10.1111/jzo.12355] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- M. Mezzasalma
- Department of Biology; University of Naples Federico II; Naples Italy
| | - V. Visone
- Department of Biology; University of Naples Federico II; Naples Italy
| | - A. Petraccioli
- Department of Biology; University of Naples Federico II; Naples Italy
| | - G. Odierna
- Department of Biology; University of Naples Federico II; Naples Italy
| | - T. Capriglione
- Department of Biology; University of Naples Federico II; Naples Italy
| | - F. M. Guarino
- Department of Biology; University of Naples Federico II; Naples Italy
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Malhotra A, Creer S, Harris JB, Thorpe RS. The importance of being genomic: Non-coding and coding sequences suggest different models of toxin multi-gene family evolution. Toxicon 2015; 107:344-58. [DOI: 10.1016/j.toxicon.2015.08.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 07/31/2015] [Accepted: 08/06/2015] [Indexed: 10/23/2022]
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Yamaguchi K, Chijiwa T, Yamamura T, Ikeda N, Yatsui T, Hayama S, Hattori S, Oda-Ueda N, Ohno M. Interisland variegation of venom [Lys(49)]phospholipase A2 isozyme genes in Protobothrops genus snakes in the southwestern islands of Japan. Toxicon 2015; 107:210-6. [PMID: 26335362 DOI: 10.1016/j.toxicon.2015.08.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 08/10/2015] [Accepted: 08/27/2015] [Indexed: 11/29/2022]
Abstract
Protobothrops tokarensis (Pt), a Crotalinae snake, inhabits only Takarajima and Kodakarajima islands of the Tokara Islands located in the immediate north of Amami-Oshima island of Japan. Kodakarajima P. tokarensis venom gland cDNA library gave four types of phospholipase A2 (PLA2) cDNAs encoding neutral [Asp(49)]PLA2, basic [Asp(49)]PLA2, highly basic [Asp(49)]PLA2, and [Lys(49)]PLA2. As the amino acid sequences encoded by their open reading frames (ORFs) were identical to those of PLA2, PLA-B, PLA-N, and BPI (a [Lys(49)]PLA2), respectively, from Amami-Oshima P. flavoviridis (Pf) venom, they were named PtPLA2, PtPLA-B, PtPLA-N, and PtBPI. Chromatography of P. tokarensis venom gave three PLA2 isozymes, PtPLA2, PtPLA-B, and PtBPI. However, BPII and BPIII ([Lys(49)]PLA2s) expressed in Amami-Oshima P. flavoviridis venom were not found in P. tokarensis venom. Genomic polymerase chain reaction (PCR) for P. tokarensis liver DNAs with the unique primers gave PtBPI gene. Notably it was found that LINE (long interspersed nuclear element)-1 fragment is inserted into second intron of PtBPI gene. The LINE-1 fragment may prevent duplication of PtBPI gene and thus formation of plural [Lys(49)]PLA2 genes in P. tokarensis genome. The interisland variegation of venom [Lys(49)]PLA2 isozyme genes in Protobothrops genus snakes in the southwestern islands of Japan is discussed.
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Affiliation(s)
- Kazuaki Yamaguchi
- Department of Applied Life Science, Faculty of Bioscience, Sojo University, 4-22-1 Ikeda, Kumamoto 860-0082, Japan
| | - Takahito Chijiwa
- Department of Applied Life Science, Faculty of Bioscience, Sojo University, 4-22-1 Ikeda, Kumamoto 860-0082, Japan.
| | - Takeshi Yamamura
- Department of Applied Life Science, Faculty of Bioscience, Sojo University, 4-22-1 Ikeda, Kumamoto 860-0082, Japan
| | - Naoki Ikeda
- Department of Applied Life Science, Faculty of Bioscience, Sojo University, 4-22-1 Ikeda, Kumamoto 860-0082, Japan
| | - Takayo Yatsui
- Department of Applied Life Science, Faculty of Bioscience, Sojo University, 4-22-1 Ikeda, Kumamoto 860-0082, Japan
| | - Setsuko Hayama
- Department of Applied Life Science, Faculty of Bioscience, Sojo University, 4-22-1 Ikeda, Kumamoto 860-0082, Japan
| | - Shosaku Hattori
- Institute of Medical Science, University of Tokyo, Oshima-gun, Kagoshima 894-1531, Japan
| | - Naoko Oda-Ueda
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Sojo University, 4-22-1 Ikeda, Kumamoto 860-0082, Japan
| | - Motonori Ohno
- Department of Applied Life Science, Faculty of Bioscience, Sojo University, 4-22-1 Ikeda, Kumamoto 860-0082, Japan
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Affiliation(s)
- Juan J Calvete
- Instituto de Biomedicina de Valencia, CSIC, Valencia, Spain.
| | - Bruno Lomonte
- Instituto Clodomiro Picado, Universidad de Costa Rica, Costa Rica.
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Aird SD, Aggarwal S, Villar-Briones A, Tin MMY, Terada K, Mikheyev AS. Snake venoms are integrated systems, but abundant venom proteins evolve more rapidly. BMC Genomics 2015; 16:647. [PMID: 26315097 PMCID: PMC4552096 DOI: 10.1186/s12864-015-1832-6] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 08/07/2015] [Indexed: 12/19/2022] Open
Abstract
Background While many studies have shown that extracellular proteins evolve rapidly, how selection acts on them remains poorly understood. We used snake venoms to understand the interaction between ecology, expression level, and evolutionary rate in secreted protein systems. Venomous snakes employ well-integrated systems of proteins and organic constituents to immobilize prey. Venoms are generally optimized to subdue preferred prey more effectively than non-prey, and many venom protein families manifest positive selection and rapid gene family diversification. Although previous studies have illuminated how individual venom protein families evolve, how selection acts on venoms as integrated systems, is unknown. Results Using next-generation transcriptome sequencing and mass spectrometry, we examined microevolution in two pitvipers, allopatrically separated for at least 1.6 million years, and their hybrids. Transcriptomes of parental species had generally similar compositions in regard to protein families, but for a given protein family, the homologs present and concentrations thereof sometimes differed dramatically. For instance, a phospholipase A2 transcript comprising 73.4 % of the Protobothrops elegans transcriptome, was barely present in the P. flavoviridis transcriptome (<0.05 %). Hybrids produced most proteins found in both parental venoms. Protein evolutionary rates were positively correlated with transcriptomic and proteomic abundances, and the most abundant proteins showed positive selection. This pattern holds with the addition of four other published crotaline transcriptomes, from two more genera, and also for the recently published king cobra genome, suggesting that rapid evolution of abundant proteins may be generally true for snake venoms. Looking more broadly at Protobothrops, we show that rapid evolution of the most abundant components is due to positive selection, suggesting an interplay between abundance and adaptation. Conclusions Given log-scale differences in toxin abundance, which are likely correlated with biosynthetic costs, we hypothesize that as a result of natural selection, snakes optimize return on energetic investment by producing more of venom proteins that increase their fitness. Natural selection then acts on the additive genetic variance of these components, in proportion to their contributions to overall fitness. Adaptive evolution of venoms may occur most rapidly through changes in expression levels that alter fitness contributions, and thus the strength of selection acting on specific secretome components. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1832-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Steven D Aird
- Okinawa Institute of Science and Technology Graduate University, Tancha 1919-1, Onna-son, Kunigami-gun, Okinawa-ken, 904-0412, Japan.
| | - Shikha Aggarwal
- Okinawa Institute of Science and Technology Graduate University, Tancha 1919-1, Onna-son, Kunigami-gun, Okinawa-ken, 904-0412, Japan. .,University School of Environment Management, Guru Gobind Singh Indraprastha University, Sector 16C, Dwarka, New Delhi, 110078, India.
| | - Alejandro Villar-Briones
- Okinawa Institute of Science and Technology Graduate University, Tancha 1919-1, Onna-son, Kunigami-gun, Okinawa-ken, 904-0412, Japan.
| | - Mandy Man-Ying Tin
- Okinawa Institute of Science and Technology Graduate University, Tancha 1919-1, Onna-son, Kunigami-gun, Okinawa-ken, 904-0412, Japan.
| | - Kouki Terada
- Okinawa Prefectural Institute of Health and the Environment, Biology and Ecology Group, 2003 Ozato, Ozato, Nanjo-shi, Okinawa, 901-1202, Japan.
| | - Alexander S Mikheyev
- Okinawa Institute of Science and Technology Graduate University, Tancha 1919-1, Onna-son, Kunigami-gun, Okinawa-ken, 904-0412, Japan. .,Research School of Biology, Australian National University, Canberra, ACT 0200, Australia.
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The finding of a group IIE phospholipase A2 gene in a specified segment of Protobothrops flavoviridis genome and its possible evolutionary relationship to group IIA phospholipase A2 genes. Toxins (Basel) 2014; 6:3471-87. [PMID: 25529307 PMCID: PMC4280545 DOI: 10.3390/toxins6123471] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 12/05/2014] [Accepted: 12/15/2014] [Indexed: 01/22/2023] Open
Abstract
The genes encoding group IIE phospholipase A2, abbreviated as IIE PLA2, and its 5' and 3' flanking regions of Crotalinae snakes such as Protobothrops flavoviridis, P. tokarensis, P. elegans, and Ovophis okinavensis, were found and sequenced. The genes consisted of four exons and three introns and coded for 22 or 24 amino acid residues of the signal peptides and 134 amino acid residues of the mature proteins. These IIE PLA2s show high similarity to those from mammals and Colubridae snakes. The high expression level of IIE PLA2s in Crotalinae venom glands suggests that they should work as venomous proteins. The blast analysis indicated that the gene encoding OTUD3, which is ovarian tumor domain-containing protein 3, is located in the 3' downstream of IIE PLA2 gene. Moreover, a group IIA PLA2 gene was found in the 5' upstream of IIE PLA2 gene linked to the OTUD3 gene (OTUD3) in the P. flavoviridis genome. It became evident that the specified arrangement of IIA PLA2 gene, IIE PLA2 gene, and OTUD3 in this order is common in the genomes of humans to snakes. The present finding that the genes encoding various secretory PLA2s form a cluster in the genomes of humans to birds is closely related to the previous finding that six venom PLA2 isozyme genes are densely clustered in the so-called NIS-1 fragment of the P. flavoviridis genome. It is also suggested that venom IIA PLA2 genes may be evolutionarily derived from the IIE PLA2 gene.
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Yamashiro ET, Oliveira AK, Kitano ES, Menezes MC, Junqueira-de-Azevedo IL, Paes Leme AF, Serrano SM. Proteoforms of the platelet-aggregating enzyme PA-BJ, a serine proteinase from Bothrops jararaca venom. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:2068-76. [DOI: 10.1016/j.bbapap.2014.09.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 09/08/2014] [Accepted: 09/09/2014] [Indexed: 10/24/2022]
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Hargreaves AD, Swain MT, Hegarty MJ, Logan DW, Mulley JF. Restriction and recruitment-gene duplication and the origin and evolution of snake venom toxins. Genome Biol Evol 2014; 6:2088-95. [PMID: 25079342 PMCID: PMC4231632 DOI: 10.1093/gbe/evu166] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2014] [Indexed: 11/23/2022] Open
Abstract
Snake venom has been hypothesized to have originated and diversified through a process that involves duplication of genes encoding body proteins with subsequent recruitment of the copy to the venom gland, where natural selection acts to develop or increase toxicity. However, gene duplication is known to be a rare event in vertebrate genomes, and the recruitment of duplicated genes to a novel expression domain (neofunctionalization) is an even rarer process that requires the evolution of novel combinations of transcription factor binding sites in upstream regulatory regions. Therefore, although this hypothesis concerning the evolution of snake venom is very unlikely and should be regarded with caution, it is nonetheless often assumed to be established fact, hindering research into the true origins of snake venom toxins. To critically evaluate this hypothesis, we have generated transcriptomic data for body tissues and salivary and venom glands from five species of venomous and nonvenomous reptiles. Our comparative transcriptomic analysis of these data reveals that snake venom does not evolve through the hypothesized process of duplication and recruitment of genes encoding body proteins. Indeed, our results show that many proposed venom toxins are in fact expressed in a wide variety of body tissues, including the salivary gland of nonvenomous reptiles and that these genes have therefore been restricted to the venom gland following duplication, not recruited. Thus, snake venom evolves through the duplication and subfunctionalization of genes encoding existing salivary proteins. These results highlight the danger of the elegant and intuitive "just-so story" in evolutionary biology.
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Affiliation(s)
| | - Martin T Swain
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, United Kingdom
| | - Matthew J Hegarty
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, United Kingdom
| | - Darren W Logan
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - John F Mulley
- School of Biological Sciences, Bangor University, United Kingdom
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Boycheva S, Daviet L, Wolfender JL, Fitzpatrick TB. The rise of operon-like gene clusters in plants. TRENDS IN PLANT SCIENCE 2014; 19:447-59. [PMID: 24582794 DOI: 10.1016/j.tplants.2014.01.013] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 01/19/2014] [Accepted: 01/30/2014] [Indexed: 05/18/2023]
Abstract
Gene clusters are common features of prokaryotic genomes also present in eukaryotes. Most clustered genes known are involved in the biosynthesis of secondary metabolites. Although horizontal gene transfer is a primary source of prokaryotic gene cluster (operon) formation and has been reported to occur in eukaryotes, the predominant source of cluster formation in eukaryotes appears to arise de novo or through gene duplication followed by neo- and sub-functionalization or translocation. Here we aim to provide an overview of the current knowledge and open questions related to plant gene cluster functioning, assembly, and regulation. We also present potential research approaches and point out the benefits of a better understanding of gene clusters in plants for both fundamental and applied plant science.
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Affiliation(s)
- Svetlana Boycheva
- Department of Botany and Plant Biology, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva 4, Switzerland
| | - Laurent Daviet
- Biotechnology Department, Corporate R&D Division, FIRMENICH SA, 1211 Geneva 4, Switzerland
| | - Jean-Luc Wolfender
- School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Quai Ernest-Ansermet 30, CH-1211 Geneva 4, Switzerland
| | - Teresa B Fitzpatrick
- Department of Botany and Plant Biology, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva 4, Switzerland.
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Accelerated Evolution of Fetuin Family Proteins inProtobothrops flavoviridis(Habu Snake) Serum and the Discovery of an L1-Like Genomic Element in the Intronic Sequence of a Fetuin-Encoding Gene. Biosci Biotechnol Biochem 2014; 77:582-90. [DOI: 10.1271/bbb.120829] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Whittington CM, Belov K. Tracing monotreme venom evolution in the genomics era. Toxins (Basel) 2014; 6:1260-73. [PMID: 24699339 PMCID: PMC4014732 DOI: 10.3390/toxins6041260] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 03/17/2014] [Accepted: 03/27/2014] [Indexed: 01/07/2023] Open
Abstract
The monotremes (platypuses and echidnas) represent one of only four extant venomous mammalian lineages. Until recently, monotreme venom was poorly understood. However, the availability of the platypus genome and increasingly sophisticated genomic tools has allowed us to characterize platypus toxins, and provides a means of reconstructing the evolutionary history of monotreme venom. Here we review the physiology of platypus and echidna crural (venom) systems as well as pharmacological and genomic studies of monotreme toxins. Further, we synthesize current ideas about the evolution of the venom system, which in the platypus is likely to have been retained from a venomous ancestor, whilst being lost in the echidnas. We also outline several research directions and outstanding questions that would be productive to address in future research. An improved characterization of mammalian venoms will not only yield new toxins with potential therapeutic uses, but will also aid in our understanding of the way that this unusual trait evolves.
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Affiliation(s)
- Camilla M Whittington
- School of Biological Sciences, The University of Sydney, Camperdown, NSW 2006, Australia.
| | - Katherine Belov
- Faculty of Veterinary Science, The University of Sydney, Camperdown, NSW 2006, Australia.
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Durban J, Pérez A, Sanz L, Gómez A, Bonilla F, Rodríguez S, Chacón D, Sasa M, Angulo Y, Gutiérrez JM, Calvete JJ. Integrated "omics" profiling indicates that miRNAs are modulators of the ontogenetic venom composition shift in the Central American rattlesnake, Crotalus simus simus. BMC Genomics 2013; 14:234. [PMID: 23575160 PMCID: PMC3660174 DOI: 10.1186/1471-2164-14-234] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 03/14/2013] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Understanding the processes that drive the evolution of snake venom is a topic of great research interest in molecular and evolutionary toxinology. Recent studies suggest that ontogenetic changes in venom composition are genetically controlled rather than environmentally induced. However, the molecular mechanisms underlying these changes remain elusive. Here we have explored the basis and level of regulation of the ontogenetic shift in the venom composition of the Central American rattlesnake, Crotalus s. simus using a combined proteomics and transcriptomics approach. RESULTS Proteomic analysis showed that the ontogenetic shift in the venom composition of C. s. simus is essentially characterized by a gradual reduction in the expression of serine proteinases and PLA2 molecules, particularly crotoxin, a β-neurotoxic heterodimeric PLA2, concominantly with an increment of PI and PIII metalloproteinases at age 9-18 months. Comparison of the transcriptional activity of the venom glands of neonate and adult C. s. simus specimens indicated that their transcriptomes exhibit indistinguisable toxin family profiles, suggesting that the elusive mechanism by which shared transcriptomes generate divergent venom phenotypes may operate post-transcriptionally. Specifically, miRNAs with frequency count of 1000 or greater exhibited an uneven distribution between the newborn and adult datasets. Of note, 590 copies of a miRNA targeting crotoxin B-subunit was exclusively found in the transcriptome of the adult snake, whereas 1185 copies of a miRNA complementary to a PIII-SVMP mRNA was uniquely present in the newborn dataset. These results support the view that age-dependent changes in the concentration of miRNA modulating the transition from a crotoxin-rich to a SVMP-rich venom from birth through adulthood can potentially explain what is observed in the proteomic analysis of the ontogenetic changes in the venom composition of C. s. simus. CONCLUSIONS Existing snake venom toxins are the result of early recruitment events in the Toxicofera clade of reptiles by which ordinary genes were duplicated, and the new genes selectively expressed in the venom gland and amplified to multigene families with extensive neofunctionalization throughout the approximately 112-125 million years of ophidian evolution. Our findings support the view that understanding the phenotypic diversity of snake venoms requires a deep knowledge of the mechanisms regulating the transcriptional and translational activity of the venom gland. Our results suggest a functional role for miRNAs. The impact of specific miRNAs in the modulation of venom composition, and the integration of the mechanisms responsible for the generation of these miRNAs in the evolutionary landscape of the snake's venom gland, are further challenges for future research.
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Affiliation(s)
- Jordi Durban
- Instituto de Biomedicina de Valencia, Consejo Superior de Investigaciones Científicas, Jaime Roig 11, Valencia 46010, Spain
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Structural characteristics and evolution of the Protobothrops elegans pancreatic phospholipase A2 gene in contrast with those of Protobothrops genus venom phospholipase A2 genes. Biosci Biotechnol Biochem 2013; 77:97-102. [PMID: 23291767 DOI: 10.1271/bbb.120595] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The nucleotide sequence of the gene encoding Protobothrops elegans (Crotalinae) pancreatic phospholipase A(2) (PLA(2)), abbreviated PePancPLA(2), was determined by means of inverted PCR techniques. Since its deduced amino acid sequence contains a pancreatic loop and shows high similarity to that of Laticauda semifasciata (Elapinae) group IB pancreatic PLA(2), PePancPLA(2) is classified into group IB PLA(2). The nucleotide sequences of the PePancPLA(2) gene, the L. semifasciata group IB pancreatic PLA(2) gene, and the L. semifasciata group IA venom PLA(2) gene are similar to one another but greatly dissimilar to those of Protobothrops genus (Crotalinae) group II venom PLA(2) genes, suggesting that the Elapinae group IB PLA(2) gene and the group IA PLA(2) gene appeared after Elapinae was established, and that the Crotalinae group II venom PLA(2) genes came into existence before Elapinae and Crotalinae diverged. A phylogenetic analysis of their amino acid sequences confirms this.
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Lomonte B, Rangel J. Snake venom Lys49 myotoxins: From phospholipases A2 to non-enzymatic membrane disruptors. Toxicon 2012; 60:520-30. [DOI: 10.1016/j.toxicon.2012.02.007] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Accepted: 02/23/2012] [Indexed: 10/28/2022]
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Sanz L, Harrison RA, Calvete JJ. First draft of the genomic organization of a PIII-SVMP gene. Toxicon 2012; 60:455-69. [PMID: 22543188 DOI: 10.1016/j.toxicon.2012.04.331] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 03/27/2012] [Accepted: 04/04/2012] [Indexed: 11/20/2022]
Abstract
The evolutionary pathway of highly toxic proteins expressed in snake venom glands from proteins without toxic function and expressed in non-parotid tissues remains poorly understood. Here we examine gene structure of a representative of a venom protein with an ADAMs metalloproteinase evolutionary origin. The structure of the 15,652 bp Echis ocellatus pre-pro EOC00089-like PIII-SVMP gene was assembled from PCR-amplified sequences of overlapping genomic fragments. The gene comprises 12 exons interrupted by 11 introns. In a homology model of the EOC00089-like protein, the insertion of introns interrupting coding regions lie just after or between secondary structure elements. Long interspersed nuclear retroelements (LINE) L2/CR1 and RTE/Bov-B, short interspersed nuclear retroelements SINE/Sauria, and a hobo-activator DNA (Charlie, hAT) transposon were identified within introns 1, 3, 7 and 8. Pairwise amino acid sequence comparisons between EOC00089-like PIII-SVMP and its closest orthologs, ADAM28, from a mammal, Homo sapiens, and the lizard, Anolis carolinensis, showed that the ORFs of these three proteins share 42%/59%, 49%/69%, and 48%/65% (identity/similarity), respectively. The protein-coding positions interrupted by each of the 11 introns of the Echis PIII-SVMP gene are entirely conserved in the A. carolinensis and human ADAM28 genes. However, the lizard and the human ADAM28 genes contain 5 introns not present in the E. ocellatus gene. Furthermore, Echis and Anolis introns exhibit quantitatively and qualitatively distinctions in their inserted retroelements. These findings identify introns as possible key elements in the recruitment and amplification process of SVMPs into the venom gland of extant snakes. Ongoing reptile genome sequencing projects may shed light on this intriguing aspect of the emergence and evolution of venom toxin genes. Furthermore, the organization of the PIII-SVMP reported here provides a genomic explanation for the emergence of dimeric disintegrin subunits encoded by short messengers.
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Affiliation(s)
- Libia Sanz
- Consejo Superior de Investigaciones Científicas, Valencia, Spain
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Castoe TA, de Koning JAP, Hall KT, Yokoyama KD, Gu W, Smith EN, Feschotte C, Uetz P, Ray DA, Dobry J, Bogden R, Mackessy SP, Bronikowski AM, Warren WC, Secor SM, Pollock DD. Sequencing the genome of the Burmese python (Python molurus bivittatus) as a model for studying extreme adaptations in snakes. Genome Biol 2011; 12:406. [PMID: 21801464 PMCID: PMC3218823 DOI: 10.1186/gb-2011-12-7-406] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The Consortium for Snake Genomics is in the process of sequencing the genome and creating transcriptomic resources for the Burmese python. Here, we describe how this will be done, what analyses this work will include, and provide a timeline.
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Castoe TA, Bronikowski AM, Brodie ED, Edwards SV, Pfrender ME, Shapiro MD, Pollock DD, Warren WC. A proposal to sequence the genome of a garter snake (Thamnophis sirtalis). Stand Genomic Sci 2011; 4:257-70. [PMID: 21677863 PMCID: PMC3111982 DOI: 10.4056/sigs.1664145] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Here we develop an argument in support of sequencing a garter snake (Thamnophis sirtalis) genome, and outline a plan to accomplish this. This snake is a common, widespread, nonvenomous North American species that has served as a model for diverse studies in evolutionary biology, physiology, genomics, behavior and coevolution. The anole lizard is currently the only genome sequence available for a non-avian reptile. Thus, the garter snake at this time would be the first available snake genome sequence and as such would provide much needed comparative representation of non-avian reptilian genomes, and would also allow critical new insights for vertebrate comparative genomic studies. We outline the major areas of discovery that the availability of the garter snake genome would enable, and describe a plan for whole-genome sequencing.
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Affiliation(s)
- Todd A. Castoe
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO
- Corresponding Author: Todd A. Castoe,
| | - Anne M. Bronikowski
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA
| | - Edmund D. Brodie
- Department of Biology, University of Virginia, Charlottesville, VA
| | - Scott V. Edwards
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA
| | | | | | - David D. Pollock
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO
| | - Wesley C. Warren
- Genome Sequencing Center, Washington University School of Medicine, St. Louis, MO
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Profiling the venom gland transcriptomes of Costa Rican snakes by 454 pyrosequencing. BMC Genomics 2011; 12:259. [PMID: 21605378 PMCID: PMC3128066 DOI: 10.1186/1471-2164-12-259] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2011] [Accepted: 05/23/2011] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND A long term research goal of venomics, of applied importance for improving current antivenom therapy, but also for drug discovery, is to understand the pharmacological potential of venoms. Individually or combined, proteomic and transcriptomic studies have demonstrated their feasibility to explore in depth the molecular diversity of venoms. In the absence of genome sequence, transcriptomes represent also valuable searchable databases for proteomic projects. RESULTS The venom gland transcriptomes of 8 Costa Rican taxa from 5 genera (Crotalus, Bothrops, Atropoides, Cerrophidion, and Bothriechis) of pitvipers were investigated using high-throughput 454 pyrosequencing. 100,394 out of 330,010 masked reads produced significant hits in the available databases. 5.165,220 nucleotides (8.27%) were masked by RepeatMasker, the vast majority of which corresponding to class I (retroelements) and class II (DNA transposons) mobile elements. BLAST hits included 79,991 matches to entries of the taxonomic suborder Serpentes, of which 62,433 displayed similarity to documented venom proteins. Strong discrepancies between the transcriptome-computed and the proteome-gathered toxin compositions were obvious at first sight. Although the reasons underlaying this discrepancy are elusive, since no clear trend within or between species is apparent, the data indicate that individual mRNA species may be translationally controlled in a species-dependent manner. The minimum number of genes from each toxin family transcribed into the venom gland transcriptome of each species was calculated from multiple alignments of reads matched to a full-length reference sequence of each toxin family. Reads encoding ORF regions of Kazal-type inhibitor-like proteins were uniquely found in Bothriechis schlegelii and B. lateralis transcriptomes, suggesting a genus-specific recruitment event during the early-Middle Miocene. A transcriptome-based cladogram supports the large divergence between A. mexicanus and A. picadoi, and a closer kinship between A. mexicanus and C. godmani. CONCLUSIONS Our comparative next-generation sequencing (NGS) analysis reveals taxon-specific trends governing the formulation of the venom arsenal. Knowledge of the venom proteome provides hints on the translation efficiency of toxin-coding transcripts, contributing thereby to a more accurate interpretation of the transcriptome. The application of NGS to the analysis of snake venom transcriptomes, may represent the tool for opening the door to systems venomics.
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Castoe TA, Hall KT, Guibotsy Mboulas ML, Gu W, de Koning APJ, Fox SE, Poole AW, Vemulapalli V, Daza JM, Mockler T, Smith EN, Feschotte C, Pollock DD. Discovery of highly divergent repeat landscapes in snake genomes using high-throughput sequencing. Genome Biol Evol 2011; 3:641-53. [PMID: 21572095 PMCID: PMC3157835 DOI: 10.1093/gbe/evr043] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We conducted a comprehensive assessment of genomic repeat content in two snake genomes, the venomous copperhead (Agkistrodon contortrix) and the Burmese python (Python molurus bivittatus). These two genomes are both relatively small (∼1.4 Gb) but have surprisingly extensive differences in the abundance and expansion histories of their repeat elements. In the python, the readily identifiable repeat element content is low (21%), similar to bird genomes, whereas that of the copperhead is higher (45%), similar to mammalian genomes. The copperhead's greater repeat content arises from the recent expansion of many different microsatellites and transposable element (TE) families, and the copperhead had 23-fold greater levels of TE-related transcripts than the python. This suggests the possibility that greater TE activity in the copperhead is ongoing. Expansion of CR1 LINEs in the copperhead genome has resulted in TE-mediated microsatellite expansion ("microsatellite seeding") at a scale several orders of magnitude greater than previously observed in vertebrates. Snakes also appear to be prone to horizontal transfer of TEs, particularly in the copperhead lineage. The reason that the copperhead has such a small genome in the face of so much recent expansion of repeat elements remains an open question, although selective pressure related to extreme metabolic performance is an obvious candidate. TE activity can affect gene regulation as well as rates of recombination and gene duplication, and it is therefore possible that TE activity played a role in the evolution of major adaptations in snakes; some evidence suggests this may include the evolution of venom repertoires.
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Affiliation(s)
- Todd A Castoe
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, USA
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Dawson K, Thorpe RS, Malhotra A. Estimating genetic variability in non-model taxa: a general procedure for discriminating sequence errors from actual variation. PLoS One 2010; 5:e15204. [PMID: 21151906 PMCID: PMC2997787 DOI: 10.1371/journal.pone.0015204] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 11/01/2010] [Indexed: 11/18/2022] Open
Abstract
Genetic variation is the driving force of evolution and as such is of central interest for biologists. However, inadequate discrimination of errors from true genetic variation could lead to incorrect estimates of gene copy number, population genetic parameters, phylogenetic relationships and the deposition of gene and protein sequences in databases that are not actually present in any organism. Misincorporation errors in multi-template PCR cloning methods, still commonly used for obtaining novel gene sequences in non-model species, are difficult to detect, as no previous information may be available about the number of expected copies of genes belonging to multi-gene families. However, studies employing these techniques rarely describe in any great detail how errors arising in the amplification process were detected and accounted for. Here, we estimated the rate of base misincorporation of a widely-used PCR-cloning method, using a single copy mitochondrial gene from a single individual to minimise variation in the template DNA, as 1.62×10(-3) errors per site, or 9.26×10(-5) per site per duplication. The distribution of errors among sequences closely matched that predicted by a binomial distribution function. The empirically estimated error rate was applied to data, obtained using the same methods, from the Phospholipase A(2) toxin family from the pitviper Ovophis monticola. The distribution of differences detected closely matched the expected distribution of errors and we conclude that, when undertaking gene discovery or assessment of genetic diversity using this error-prone method, it will be informative to empirically determine the rate of base misincorporation.
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Affiliation(s)
- Karen Dawson
- School of Biological Sciences, College of Natural Sciences, Bangor University, Bangor, Gwynedd, United Kingdom
| | - Roger S. Thorpe
- School of Biological Sciences, College of Natural Sciences, Bangor University, Bangor, Gwynedd, United Kingdom
| | - Anita Malhotra
- School of Biological Sciences, College of Natural Sciences, Bangor University, Bangor, Gwynedd, United Kingdom
- * E-mail:
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