Recombination within the Cepaea nemoralis supergene is confounded by incomplete penetrance and epistasis

Ramos Gonzalez, Daniel; Aramendia, Amaia Caro; Davison, Angus

Abstract

Although the land snail Cepaea nemoralis is one of the most thoroughly investigated colour polymorphic species, there have been few recent studies on the inheritance of the shell traits. Previously, it has been shown that the shell polymorphism is controlled by a series of nine or more loci, of which five make a single ‘supergene’ containing tightly linked colour and banding loci and more loosely linked pigmentation, spread band and punctate loci. However, one limitation of earlier work was that putative instances of recombination between loci within the supergene were not easily verified. We therefore generated a new set of C. nemoralis crosses that segregate for colour, banding and pigmentation, and several other unlinked shell phenotype loci. The snails were genotyped using a set of RAD-seq-derived loci that flank the supergene, and instances of recombination tested by comparing inferred supergene genotype against RAD-marker genotype. We found no evidence that suspected ‘recombinant’ individuals are recombinant between loci within the supergene. As point estimates of recombination between both colour/banding, and colour/pigmentation loci are zero, incomplete penetrance and epistasis are a better explanation for the apparent ‘recombinant’ phenotype of some snail shells. Overall, this work, therefore, shows that the architecture of the supergene may not be as previously supposed. It also provides a resource for fine mapping of the supergene and other major shell phenotype loci.

Citation

Ramos Gonzalez, D., Aramendia, A. C., & Davison, A. (2019). Recombination within the Cepaea nemoralis supergene is confounded by incomplete penetrance and epistasis. Heredity, 123(2), 153-161. https://doi.org/10.1038/s41437-019-0190-6

• Journal Article Type: Article
• Acceptance Date: Jan 13, 2019
• Online Publication Date: Feb 14, 2019
• Publication Date: Feb 14, 2019
• Deposit Date: Jan 29, 2019
• Publicly Available Date: Feb 18, 2019
• Journal: Heredity
• Print ISSN: 0018-067X
• Electronic ISSN: 1365-2540
• Publisher: Nature Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 123
• Issue: 2
• Pages: 153-161
• DOI: https://doi.org/10.1038/s41437-019-0190-6
• Keywords: Cepaea; colour; polymorphism; snail; supergene 11
• Public URL: https://nottingham-repository.worktribe.com/output/1503099
• Publisher URL: https://www.nature.com/articles/s41437-019-0190-6
• Additional Information: Received: 19 November 2018; Revised: 9 January 2019; Accepted: 13 January 2019; First Online: 14 February 2019; : ; : The authors declare that they have no conflict of interest.
• Contract Date: Feb 18, 2019