Foraging environment determines the genetic architecture and evolutionary potential of trophic morphology in cichlid fishes

Parsons, K. J. , Concannon, M., Navon, D., Wang, J., Ea, I., Groveas, K., Campbell, C. and Albertson, R. C. (2016) Foraging environment determines the genetic architecture and evolutionary potential of trophic morphology in cichlid fishes. Molecular Ecology, 25(24), pp. 6012-6023. (doi: 10.1111/mec.13801) (PMID:27516345)

Abstract

Phenotypic plasticity allows organisms to change their phenotype in response to shifts in the environment. While a central topic in current discussions of evolutionary potential, a comprehensive understanding of the genetic underpinnings of plasticity is lacking in systems undergoing adaptive diversification. Here, we investigate the genetic basis of phenotypic plasticity in a textbook adaptive radiation, Lake Malawi cichlid fishes. Specifically, we crossed two divergent species to generate an F3 hybrid mapping population. At early juvenile stages, hybrid families were split and reared in alternate foraging environments that mimicked benthic/scraping or limnetic/sucking modes of feeding. These alternate treatments produced a variation in morphology that was broadly similar to the major axis of divergence among Malawi cichlids, providing support for the flexible stem theory of adaptive radiation. Next, we found that the genetic architecture of several morphological traits was highly sensitive to the environment. In particular, of 22 significant quantitative trait loci (QTL), only one was shared between the environments. In addition, we identified QTL acting across environments with alternate alleles being differentially sensitive to the environment. Thus, our data suggest that while plasticity is largely determined by loci specific to a given environment, it may also be influenced by loci operating across environments. Finally, our mapping data provide evidence for the evolution of plasticity via genetic assimilation at an important regulatory locus, ptch1. In all, our data address long-standing discussions about the genetic basis and evolution of plasticity. They also underscore the importance of the environment in affecting developmental outcomes, genetic architectures, morphological diversity and evolutionary potential.

• Item Type: Articles
• Additional Information: This work was supported by start up funds from the University of Glasgow to K. J. P. and a grant to R.C. A. from the NSF (IOS-1054909).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Parsons, Dr Kevin
• Authors: Parsons, K. J., Concannon, M., Navon, D., Wang, J., Ea, I., Groveas, K., Campbell, C., and Albertson, R. C.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Molecular Ecology
• Publisher: Wiley
• ISSN: 0962-1083
• ISSN (Online): 1365-294X
• Published Online: 12 August 2016
• Copyright Holders: Copyright © 2016 John Wiley and Sons Ltd
• First Published: First published in Molecular Ecology 25(24):6012-6023
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher