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© 2024. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.

Abstract

Adaptive divergence in response to environmental clines are expected to be common in species occupying heterogeneous environments. Despite numerous advances in techniques appropriate for non-model species, gene–environment association studies in elasmobranchs are still scarce. The bronze whaler or copper shark (Carcharhinus brachyurus) is a large coastal shark with a wide distribution and one of the most exploited elasmobranchs in southern Africa. Here, we assessed the distribution of neutral and adaptive genomic diversity in C. brachyurus across a highly heterogeneous environment in southern Africa based on genome-wide SNPs obtained through a restriction site-associated DNA method (3RAD). A combination of differentiation-based genome-scan (outflank) and genotype–environment analyses (redundancy analysis, latent factor mixed models) identified a total of 234 differentiation-based outlier and candidate SNPs associated with bioclimatic variables. Analysis of 26,299 putatively neutral SNPs revealed moderate and evenly distributed levels of genomic diversity across sites from the east coast of South Africa to Angola. Multivariate and clustering analyses demonstrated a high degree of gene flow with no significant population structuring among or within ocean basins. In contrast, the putatively adaptive SNPs demonstrated the presence of two clusters and deep divergence between Angola and all other individuals from Namibia and South Africa. These results provide evidence for adaptive divergence in response to a heterogeneous seascape in a large, mobile shark despite high levels of gene flow. These results are expected to inform management strategies and policy at the national and regional level for conservation of C. brachyurus populations.

Details

Title
Local adaptation with gene flow in a highly dispersive shark
Author
Klein, Juliana D 1   VIAFID ORCID Logo  ; Maduna, Simo N 2   VIAFID ORCID Logo  ; Dicken, Matthew L 3 ; da Silva, Charlene 4 ; Soekoe, Michelle 5 ; McCord, Meaghen E 6 ; Potts, Warren M 7 ; Hagen, Snorre B 2 ; Aletta E. Bester-van der Merwe 1 

 Molecular Breeding and Biodiversity Research Group, Department of Genetics, Stellenbosch University, Stellenbosch, South Africa 
 Department of Ecosystems in the Barents Region, Svanhovd Research Station, Norwegian Institute of Bioeconomy Research—NIBIO, Svanvik, Norway 
 KwaZulu-Natal Sharks Board, Umhlanga Rocks, South Africa; Institute for Coastal and Marine Research (CMR), Ocean Sciences Campus, Nelson Mandela University, Gqeberha, South Africa 
 Department of Forestry, Fisheries and Environment, Rogge Bay, South Africa 
 Division of Marine Science, Reel Science Coalition, Cape Town, South Africa 
 South African Shark Conservancy, Hermanus, South Africa; Canadian Parks and Wilderness Society, Vancouver, British Columbia, Canada 
 Department of Ichthyology and Fisheries Science, Rhodes University, Makhanda, South Africa; South African Institute for Aquatic Biodiversity, Makhanda, South Africa 
Section
ORIGINAL ARTICLES
Publication year
2024
Publication date
Jan 2024
Publisher
John Wiley & Sons, Inc.
e-ISSN
17524571
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2919732754
Copyright
© 2024. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.