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Genetic variability and the ecology of geographic range: A test of the central‐marginal hypothesis in Australian scincid lizards

For many species, both local abundance and regional occupancy are highest near the centre of their geographic distributions. One hypothesis for this pattern is that niche suitability declines with increasing distance from a species geographic centre, such that populations near range margins are char...

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Autores principales: Singhal, Sonal, Wrath, John, Rabosky, Daniel L.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545263/
https://www.ncbi.nlm.nih.gov/pubmed/35779002
http://dx.doi.org/10.1111/mec.16589
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author Singhal, Sonal
Wrath, John
Rabosky, Daniel L.
author_facet Singhal, Sonal
Wrath, John
Rabosky, Daniel L.
author_sort Singhal, Sonal
collection PubMed
description For many species, both local abundance and regional occupancy are highest near the centre of their geographic distributions. One hypothesis for this pattern is that niche suitability declines with increasing distance from a species geographic centre, such that populations near range margins are characterized by reduced density and increased patchiness. In these smaller edge populations, genetic drift is more powerful, leading to the loss of genetic diversity. This simple verbal model has been formalized as the central‐marginal hypothesis, which predicts that core populations should have greater genetic diversity than edge populations. Here, we tested the central‐marginal hypothesis using a genomic data set of 25 species‐level taxa of Australian scincid lizards in the genera Ctenotus and Lerista. A majority of taxa in our data set showed range‐wide patterns of genetic variation consistent with central‐marginal hypothesis, and eight of 25 taxa showed significantly greater genetic diversity in the centre of their range. We then explored biological, historical, and methodological factors that might predict which taxa support the central‐marginal hypothesis. We found that taxa with the strongest evidence for range expansion were the least likely to follow predictions of the central‐marginal hypothesis. The majority of these taxa had range expansions that originated at the range edge, which led to a gradient of decreasing genetic diversity from the range edge to the core, contrary to the central‐marginal hypothesis.
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spelling pubmed-95452632022-10-14 Genetic variability and the ecology of geographic range: A test of the central‐marginal hypothesis in Australian scincid lizards Singhal, Sonal Wrath, John Rabosky, Daniel L. Mol Ecol ORIGINAL ARTICLES For many species, both local abundance and regional occupancy are highest near the centre of their geographic distributions. One hypothesis for this pattern is that niche suitability declines with increasing distance from a species geographic centre, such that populations near range margins are characterized by reduced density and increased patchiness. In these smaller edge populations, genetic drift is more powerful, leading to the loss of genetic diversity. This simple verbal model has been formalized as the central‐marginal hypothesis, which predicts that core populations should have greater genetic diversity than edge populations. Here, we tested the central‐marginal hypothesis using a genomic data set of 25 species‐level taxa of Australian scincid lizards in the genera Ctenotus and Lerista. A majority of taxa in our data set showed range‐wide patterns of genetic variation consistent with central‐marginal hypothesis, and eight of 25 taxa showed significantly greater genetic diversity in the centre of their range. We then explored biological, historical, and methodological factors that might predict which taxa support the central‐marginal hypothesis. We found that taxa with the strongest evidence for range expansion were the least likely to follow predictions of the central‐marginal hypothesis. The majority of these taxa had range expansions that originated at the range edge, which led to a gradient of decreasing genetic diversity from the range edge to the core, contrary to the central‐marginal hypothesis. John Wiley and Sons Inc. 2022-07-14 2022-08 /pmc/articles/PMC9545263/ /pubmed/35779002 http://dx.doi.org/10.1111/mec.16589 Text en © 2022 The Authors. Molecular Ecology published by John Wiley & Sons Ltd. https://creativecommons.org/licenses/by-nc/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc/4.0/ (https://creativecommons.org/licenses/by-nc/4.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
spellingShingle ORIGINAL ARTICLES
Singhal, Sonal
Wrath, John
Rabosky, Daniel L.
Genetic variability and the ecology of geographic range: A test of the central‐marginal hypothesis in Australian scincid lizards
title Genetic variability and the ecology of geographic range: A test of the central‐marginal hypothesis in Australian scincid lizards
title_full Genetic variability and the ecology of geographic range: A test of the central‐marginal hypothesis in Australian scincid lizards
title_fullStr Genetic variability and the ecology of geographic range: A test of the central‐marginal hypothesis in Australian scincid lizards
title_full_unstemmed Genetic variability and the ecology of geographic range: A test of the central‐marginal hypothesis in Australian scincid lizards
title_short Genetic variability and the ecology of geographic range: A test of the central‐marginal hypothesis in Australian scincid lizards
title_sort genetic variability and the ecology of geographic range: a test of the central‐marginal hypothesis in australian scincid lizards
topic ORIGINAL ARTICLES
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545263/
https://www.ncbi.nlm.nih.gov/pubmed/35779002
http://dx.doi.org/10.1111/mec.16589
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