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When homoplasy mimics hybridization: a case study of Cape hakes (Merluccius capensis and M. paradoxus)

In the marine environment, an increasing number of studies have documented introgression and hybridization using genetic markers. Hybridization appears to occur preferentially between sister-species, with the probability of introgression decreasing with an increase in evolutionary divergence. Except...

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Autores principales: Henriques, Romina, von der Heyden, Sophie, Matthee, Conrad A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: PeerJ Inc. 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4824878/
https://www.ncbi.nlm.nih.gov/pubmed/27069785
http://dx.doi.org/10.7717/peerj.1827
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author Henriques, Romina
von der Heyden, Sophie
Matthee, Conrad A.
author_facet Henriques, Romina
von der Heyden, Sophie
Matthee, Conrad A.
author_sort Henriques, Romina
collection PubMed
description In the marine environment, an increasing number of studies have documented introgression and hybridization using genetic markers. Hybridization appears to occur preferentially between sister-species, with the probability of introgression decreasing with an increase in evolutionary divergence. Exceptions to this pattern were reported for the Cape hakes (Merluccius capensis and M. paradoxus), two distantly related Merluciidae species that diverged 3–4.2 million years ago. Yet, it is expected that contemporary hybridization between such divergent species would result in reduced hybrid fitness. We analysed 1,137 hake individuals using nine microsatellite markers and control region mtDNA data to assess the validity of the described hybridization event. To distinguish between interbreeding, ancestral polymorphism and homplasy we sequenced the flanking region of the most divergent microsatellite marker. Simulation and empirical analyses showed that hybrid identification significantly varied with the number of markers, model and approach used. Phylogenetic analyses based on the sequences of the flanking region of Mmerhk-3b, combined with the absence of mito-nuclear discordance, suggest that previously reported hybridization between M. paradoxus and M. capensis cannot be substantiated. Our findings highlight the need to conduct a priori simulation studies to establish the suitability of a particular set of microsatellite loci for detecting multiple hybridization events. In our example, the identification of hybrids was severely influenced by the number of loci and their variability, as well as the different models employed. More importantly, we provide quantifiable evidence showing that homoplasy mimics the effects of heterospecific crossings which can lead to the incorrect identification of hybridization.
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spelling pubmed-48248782016-04-11 When homoplasy mimics hybridization: a case study of Cape hakes (Merluccius capensis and M. paradoxus) Henriques, Romina von der Heyden, Sophie Matthee, Conrad A. PeerJ Aquaculture, Fisheries and Fish Science In the marine environment, an increasing number of studies have documented introgression and hybridization using genetic markers. Hybridization appears to occur preferentially between sister-species, with the probability of introgression decreasing with an increase in evolutionary divergence. Exceptions to this pattern were reported for the Cape hakes (Merluccius capensis and M. paradoxus), two distantly related Merluciidae species that diverged 3–4.2 million years ago. Yet, it is expected that contemporary hybridization between such divergent species would result in reduced hybrid fitness. We analysed 1,137 hake individuals using nine microsatellite markers and control region mtDNA data to assess the validity of the described hybridization event. To distinguish between interbreeding, ancestral polymorphism and homplasy we sequenced the flanking region of the most divergent microsatellite marker. Simulation and empirical analyses showed that hybrid identification significantly varied with the number of markers, model and approach used. Phylogenetic analyses based on the sequences of the flanking region of Mmerhk-3b, combined with the absence of mito-nuclear discordance, suggest that previously reported hybridization between M. paradoxus and M. capensis cannot be substantiated. Our findings highlight the need to conduct a priori simulation studies to establish the suitability of a particular set of microsatellite loci for detecting multiple hybridization events. In our example, the identification of hybrids was severely influenced by the number of loci and their variability, as well as the different models employed. More importantly, we provide quantifiable evidence showing that homoplasy mimics the effects of heterospecific crossings which can lead to the incorrect identification of hybridization. PeerJ Inc. 2016-03-28 /pmc/articles/PMC4824878/ /pubmed/27069785 http://dx.doi.org/10.7717/peerj.1827 Text en ©2016 Henriques et al. http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ) and either DOI or URL of the article must be cited.
spellingShingle Aquaculture, Fisheries and Fish Science
Henriques, Romina
von der Heyden, Sophie
Matthee, Conrad A.
When homoplasy mimics hybridization: a case study of Cape hakes (Merluccius capensis and M. paradoxus)
title When homoplasy mimics hybridization: a case study of Cape hakes (Merluccius capensis and M. paradoxus)
title_full When homoplasy mimics hybridization: a case study of Cape hakes (Merluccius capensis and M. paradoxus)
title_fullStr When homoplasy mimics hybridization: a case study of Cape hakes (Merluccius capensis and M. paradoxus)
title_full_unstemmed When homoplasy mimics hybridization: a case study of Cape hakes (Merluccius capensis and M. paradoxus)
title_short When homoplasy mimics hybridization: a case study of Cape hakes (Merluccius capensis and M. paradoxus)
title_sort when homoplasy mimics hybridization: a case study of cape hakes (merluccius capensis and m. paradoxus)
topic Aquaculture, Fisheries and Fish Science
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4824878/
https://www.ncbi.nlm.nih.gov/pubmed/27069785
http://dx.doi.org/10.7717/peerj.1827
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