The Evolution and Development of Wing Patterns

Heliconius erato and H. melpomene have evolved over 20 distinct geographic races that are convergent between the species due to mimicry, offering an excellent opportunity to study the genetic basis of phenotypic adaptation.

Richard Wallbank at a microscope

Different races can be crossed together and show that colour pattern divergence has a relatively simple genetic basis – few genes control most of the dramatic colour pattern differences between races. Furthermore, the same genes are repeatedly involved in convergent evolution. Between H. melpomene and H. erato, this is a result of independent evolution of convergent patterns, but in more closely related species this is through exchange of patterns by hybridization.

Pigments developing in a pupal wing of Heliconius

This raise the question of why particular genes are targeted by evolution – we hope that by understanding the gene networks that control patterning, we will be able to address this question of why evolution is constrained to particular genetic solutions, but at the same time these few loci can control such a vast array of diversity in patterns.

We have been using CRISPR to study the function of wing patterning genes and their cis-regulatory elements.

The loci that switch between major phenotypic pattern elements are controlled by cis-regulatory elements that have a very modular structure (Wallbank et al., 2016). Particular elements turn genes on in specific regions of the developing wing.

Publications

Livraghi, L. et al. A long noncoding RNA at the cortex locus controls adaptive coloration in butterflies. Proceedings of the National Academy of Sciences 121, e2403326121 (2024).

Concha, C. et al. Interplay between Developmental Flexibility and Determinism in the Evolution of Mimetic Heliconius Wing Patterns. Current Biology29, 3996-4009.e4 (2019). 

Mazo-Vargas, A. et al. Macroevolutionary shifts of WntA function potentiate butterfly wing-pattern diversity. PNAS114, 10701–10706 (2017). 

Nadeau, N. J. et al. The gene cortex controls mimicry and crypsis in butterflies and moths. Nature534, 106–110 (2016).

Ferguson, L. C., Maroja, L. & Jiggins, C. D. Convergent, modular expression of ebony and tan in the mimetic wing patterns of Heliconius butterflies. Development Genes and Evolution221, 297–308 (2011). 

Hines, H. M. et al. A wing patterning gene redefines the mimetic history of Heliconius butterflies. Proc Natl Acad Sci U S A108, 19666–19671 (2011). 

Reed, R. D. et al. optix Drives the Repeated Convergent Evolution of Butterfly Wing Pattern Mimicry. Science333, 1137–1141 (2011).