Secondary contact seeds phenotypic novelty in cichlid fishes

Nichols, Paul; Genner, Martin J.; van Oosterhout, Cock; Smith, Alan; Parsons, Paul; Sungani, Harold; Swanstrom, Jennifer; Joyce, Domino A.

Abstract

Theory proposes that genomic admixture between formerly reproductively isolated populations can generate phenotypic novelty for selection to act upon. Secondary contact may therefore be a significant promoter of phenotypic novelty that allows species to overcome environmental challenges and adapt to novel environments, including during adaptive radiation. To date, this has largely been considered from the perspective of interspecific hybridization at contact zones. However, it is also possible that this process occurs more commonly between natural populations of a single species, and thus its importance in adaptive evolution may have been underestimated. In this study, we tested the consequences of genomic introgression during apparent secondary contact between phenotypically similar lineages of the riverine cichlid fish Astatotilapia calliptera. We provide population genetic evidence of a secondary contact zone in the wild, and then demonstrate using mate-choice experiments that both lineages can reproduce together successfully in laboratory conditions. Finally, we show that genomically admixed individuals display extreme phenotypes not observed in the parental lineages. Collectively, the evidence shows that secondary contact can drive the evolution of phenotypic novelty, suggesting that pulses of secondary contact may repeatedly seed genetic novelty, which when coupled with ecological opportunity could promote rapid adaptive evolution in natural circumstances.

Citation

Nichols, P., Genner, M. J., van Oosterhout, C., Smith, A., Parsons, P., Sungani, H., …Joyce, D. A. (2015). Secondary contact seeds phenotypic novelty in cichlid fishes. Proceedings of the Royal Society B: Biological Sciences, 282(1798), Article ARTN 20142272. https://doi.org/10.1098/rspb.2014.2272

• Journal Article Type: Article
• Acceptance Date: Oct 14, 2014
• Online Publication Date: Jan 7, 2015
• Publication Date: Jan 7, 2015
• Deposit Date: Dec 17, 2015
• Publicly Available Date: Nov 23, 2017
• Journal: Proceedings of the Royal Society. B, Biological sciences
• Print ISSN: 0962-8452
• Electronic ISSN: 1471-2954
• Publisher: The Royal Society
• Peer Reviewed: Peer Reviewed
• Volume: 282
• Issue: 1798
• Article Number: ARTN 20142272
• DOI: https://doi.org/10.1098/rspb.2014.2272
• Keywords: Introgression, Admixture, Secondary contact, Phenotypic novelty, Haplochromine fishes, River capture
• Public URL: https://hull-repository.worktribe.com/output/383046