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Secondary contact seeds phenotypic novelty in cichlid fishes.

Nichols P, Genner MJ, van Oosterhout C, Smith A, Parsons P, Sungani H, Swanstrom J, Joyce DA - Proc. Biol. Sci. (2015)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: School of Biological, Biomedical and Environmental Sciences, University of Hull, Hull HU6 7RX, UK.

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.

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Mate choice of A. calliptera. In each of the four experimental replicates where females were given a free choice of males, they showed an overall but not complete preference for males from their own population. (Online version in colour.)
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RSPB20142272F2: Mate choice of A. calliptera. In each of the four experimental replicates where females were given a free choice of males, they showed an overall but not complete preference for males from their own population. (Online version in colour.)

Mentions: Reproductively receptive females significantly preferred to mate with males from their own population in each of four replicate trials (binomial tests: replicate 1, p = 0.0059; replicate 2, p = 0.0195; replicate 3, p = 0.0351; replicate 4, p < 0.0001; figure 2). On average, 19.5% (range 12.5–25%) of matings were with males from the other population.Figure 2.


Secondary contact seeds phenotypic novelty in cichlid fishes.

Nichols P, Genner MJ, van Oosterhout C, Smith A, Parsons P, Sungani H, Swanstrom J, Joyce DA - Proc. Biol. Sci. (2015)

Mate choice of A. calliptera. In each of the four experimental replicates where females were given a free choice of males, they showed an overall but not complete preference for males from their own population. (Online version in colour.)
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4262179&req=5

RSPB20142272F2: Mate choice of A. calliptera. In each of the four experimental replicates where females were given a free choice of males, they showed an overall but not complete preference for males from their own population. (Online version in colour.)
Mentions: Reproductively receptive females significantly preferred to mate with males from their own population in each of four replicate trials (binomial tests: replicate 1, p = 0.0059; replicate 2, p = 0.0195; replicate 3, p = 0.0351; replicate 4, p < 0.0001; figure 2). On average, 19.5% (range 12.5–25%) of matings were with males from the other population.Figure 2.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: School of Biological, Biomedical and Environmental Sciences, University of Hull, Hull HU6 7RX, UK.

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.

Show MeSH