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Gretgrix LJ, Decker O, Green PT, Köhler F, Moussalli A, Murphy NP. Genetic diversity of a short-ranged endemic terrestrial snail. Ecol Evol 2023; 13:e10785. [PMID: 38034337 PMCID: PMC10684984 DOI: 10.1002/ece3.10785] [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: 04/17/2023] [Revised: 11/02/2023] [Accepted: 11/17/2023] [Indexed: 12/02/2023] Open
Abstract
The factors that influence population structure and connectivity are unknown for most terrestrial invertebrates but are of particular interest both for understanding the impacts of disturbance and for determining accurate levels of biodiversity and local endemism. The main objective of this study was to determine the historical patterns of genetic differentiation and contemporary gene flow in the terrestrial snail, Austrochloritis kosciuszkoensis (Shea & O. L. Griffiths, 2010). Snails were collected in the Mt Buffalo and Alpine National Parks in Victoria, in a bid to understand how populations of this species are connected both within continuous habitat and between adjacent, yet separate environments. Utilising both mitochondrial DNA (mtDNA) and single nucleotide polymorphism (SNP) data, the degree of population structure was determined within and between sites. Very high levels of genetic divergence were found between the Mt Buffalo and Alpine snails, with no evidence for genetic exchange detected between the two regions, indicating speciation has possibly occurred between the two regions. Our analyses of the combined mtDNA and nDNA (generated from SNPs) data have revealed patterns of genetic diversity that are consistent with a history of long-term isolation and limited connectivity. This history may be related to past cycles of changes to the climate over hundreds of thousands of years, which have, in part, caused the fragmentation of Australian forests. Within both regions, extremely limited gene flow between separate populations suggests that these land snails have very limited dispersal capabilities across existing landscape barriers, especially at Mt Buffalo: here, populations only 5 km apart from each other are genetically differentiated. The distinct genetic divergences and clearly reduced dispersal ability detected in this data explain the likely existence of at least two previously unnamed cryptic Austrochloritis species within a 30-50 km radius, and highlight the need for more concentrated efforts to understand population structure and gene flow in terrestrial invertebrates.
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Affiliation(s)
- Lachlan J. Gretgrix
- Department of Environment and Genetics, School of Agriculture, Biomedicine and EnvironmentLa Trobe UniversityMelbourneVictoriaAustralia
| | - Orsi Decker
- Department of Environment and Genetics, School of Agriculture, Biomedicine and EnvironmentLa Trobe UniversityMelbourneVictoriaAustralia
- Bavarian National ParkNationalparkverwaltung Bayerischer WaldGrafenauGermany
| | - Peter T. Green
- Department of Environment and Genetics, School of Agriculture, Biomedicine and EnvironmentLa Trobe UniversityMelbourneVictoriaAustralia
| | | | | | - Nicholas P. Murphy
- Department of Environment and Genetics, School of Agriculture, Biomedicine and EnvironmentLa Trobe UniversityMelbourneVictoriaAustralia
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Wang X, He Z, Guo Z, Yang M, Xu S, Chen Q, Shao S, Li S, Zhong C, Duke NC, Shi S. Extensive gene flow in secondary sympatry after allopatric speciation. Natl Sci Rev 2022; 9:nwac280. [PMID: 36694801 PMCID: PMC9869077 DOI: 10.1093/nsr/nwac280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 12/04/2022] [Accepted: 12/10/2022] [Indexed: 12/15/2022] Open
Abstract
In the conventional view, species are separate gene pools delineated by reproductive isolation (RI). In an alternative view, species may also be delineated by a small set of 'speciation genes' without full RI, a view that has gained broad acceptance. A recent survey, however, suggested that the extensive literature on 'speciation with gene flow' is mostly (if not all) about exchanges in the early stages of speciation. There is no definitive evidence that the observed gene flow actually happened after speciation is completed. Here, we wish to know whether 'good species' (defined by the 'secondary sympatry' test) do continue to exchange genes and, importantly, under what conditions such exchanges can be observed. De novo whole-genome assembly and re-sequencing of individuals across the range of two closely related mangrove species (Rhizophora mucronata and R. stylosa) reveal the genomes to be well delineated in allopatry. They became sympatric in northeastern Australia but remain distinct species. Nevertheless, their genomes harbor ∼4000-10 000 introgression blocks averaging only about 3-4 Kb. These fine-grained introgressions indicate continual gene flow long after speciation as non-introgressable 'genomic islets,' ∼1.4 Kb in size, often harbor diverging genes of flower or gamete development. The fine-grained introgression in secondary sympatry may help settle the debate about sympatric vs. micro-allopatric speciation. In conclusion, true 'good species' may often continue to exchange genes but the opportunity for detection is highly constrained.
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Affiliation(s)
| | | | | | - Ming Yang
- Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA98195, USA
| | - Shaohua Xu
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou510275, China
| | - Qipian Chen
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou510275, China
| | - Shao Shao
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou510275, China
| | - Sen Li
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou510275, China
| | - Cairong Zhong
- Hainan Academy of Forestry (Hainan Academy of Mangrove), Haikou571100, China
| | - Norman C Duke
- Centre for Tropical Water and Aquatic Ecosystem Research, James Cook University, Townsville, QLD 4811, Australia
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Barnes ME, Misheva T, Supriya K, Rutledge M, Brownell SE. A Revised Measure of Acceptance of the Theory of Evolution: Introducing the MATE 2.0. CBE LIFE SCIENCES EDUCATION 2022; 21:ar10. [PMID: 35044845 PMCID: PMC9250377 DOI: 10.1187/cbe.21-05-0127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 11/15/2021] [Accepted: 11/17/2021] [Indexed: 06/14/2023]
Abstract
Hundreds of articles have explored the extent to which individuals accept evolution, and the Measure of Acceptance of the Theory of Evolution (MATE) is the most often used survey. However, research indicates the MATE has limitations, and it has not been updated since its creation more than 20 years ago. In this study, we revised the MATE using information from cognitive interviews with 62 students that revealed response process errors with the original instrument. We found that students answered items on the MATE based on constructs other than their acceptance of evolution, which led to answer choices that did not fully align with their actual acceptance. Students answered items based on their understanding of evolution and the nature of science and different definitions of evolution. We revised items on the MATE, conducted 29 cognitive interviews on the revised version, and administered it to 2881 students in 22 classes. We provide response process validity evidence for the new measure through cognitive interviews with students, structural validity through a Rasch dimensionality analysis, and concurrent validity evidence through correlations with other measures of evolution acceptance. Researchers can now measure student evolution acceptance using this new version of the survey, which we have called the MATE 2.0.
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Affiliation(s)
- M. Elizabeth Barnes
- Social Perceptions of Science Lab, Department of Biology, Middle Tennessee State University, Murfreesboro, TN 37132
| | - Taya Misheva
- Biology Education Research Lab, Research for Inclusive STEM Education Center, School of Life Sciences, Arizona State University, Tempe, AZ 85282
| | - K. Supriya
- Biology Education Research Lab, Research for Inclusive STEM Education Center, School of Life Sciences, Arizona State University, Tempe, AZ 85282
- Center for Education Innovation and Learning in the Sciences, University of California, Los Angeles, Los Angeles, CA 90095
| | - Michael Rutledge
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN 37132
| | - Sara E. Brownell
- Biology Education Research Lab, Research for Inclusive STEM Education Center, School of Life Sciences, Arizona State University, Tempe, AZ 85282
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