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Project: The Intersection Between Cell Fate Decisions and Phenotypic Diversification in a Rapidly Radiating Butterfly Lineage

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Project title

The Intersection Between Cell Fate Decisions and Phenotypic Diversification in a Rapidly Radiating Butterfly Lineage

Mentor name

W. Owen McMillan,


Gamboa, Panama

Project summary and objectives

Animal structures are made of combinations and arrangements of distinct cell types, the product of complex cell decision-making during development. But how do cells, which contain identical genetic information, decide what to be? This research addresses this fundamental biological question in a simple, yet spectacularly diverse animal structure–the color patterns on the wings of Heliconius butterflies. Although Heliconius wing patterns are highly diverse, they are created by altering the distribution of just three cell types (red, black and yellow wing scales) across the wing surface. Unlike in a complex organ, the cell decisions that create these patterns unfold on a flat canvas of non-migrating cells. This attribute greatly simplifies the process of understanding the interactions among genes and how these interactions change throughout development to create a specific pattern. This research capitalizes on this fact and emerging genomic tools to characterize the molecular decisions that determine how a developing wing cell becomes specified into one of the three different scale cell types.

In addition to the research objectives, there are opportunities to develop skills in science communication. Through partnerships with STRI’s Public Programs and science museums in the US, this project will create bilingual (English and Spanish) experiential learning resources that harness the potential of butterflies to educate a variety of audiences (school children, teachers, and life-long learners) about genes, development, natural selection, and the role that interactions among them play in generating Earth’s biodiversity.

Mentorship goals

Mentor Goals and Intern benefits:

  • This project uses a combination of tactics, including genome wide association, epigenetic profiling of chromatin accessibility, and targeted regulatory “knockouts” and “knockins” using CRISPR-Cas9, to understand how novelty evolves. The intern will benefit from integrating into an active research team, which includes several postdocs, working at the cutting edge of research connecting genotype to phenotype.
  • The training provided in this internship is meant to develop general research skills related to how to frame hypotheses and to broadly communicate science. The intern will gain experience in identifying butterflies, understanding their evolutionary history and basic ecology, and scientific communication.

List of suggested readings

McMillan, W. O., L. Livraghi, C. Concha, and J. J. Hanly.  (2020)  From patterning genes to process: unraveling the gene regulatory networks that pattern Heliconius wings. Frontiers in Ecology and Evolution 8:221

Livraghi, L., J. J. Hanly, S. M. Van Bellghem, G. Montejo-Kovacevich, E. van Der Heijden, L. S. Loh, A. Ren, I. A. Warren, J. J. Lewis, C. Concha, L. Hebberecht, C. J. Wright, J. M. Walker, J. Foley, Z. H. Goldberg, H. Arenas-Castro, C. Salazar, M. Perry, R.  Papa, A.  Martin, W. O. McMillan, W. Owen and C. D. Jiggins. (2021) Cortex cis-regulatory switches establish scale colour identity and pattern diversity in Heliconius. Elife, 10:

Concha, C., R. W. R. Wallbank, J. J. Hanly, J. Fenner, L. Livraghi, E. Santiago Rivera, D. F. Paulo, C. Arias, M. Vargas, M. Sanjeev, C. Morrison, D. Tian, P. Aguirre, S. Ferrara, J. Foley, C. Pardo-Diaz, C. Salazar, M. Linares, D. Massardo, B. A. Counterman, M, Scott, C. D. Jiggins, R. Papa, A. Martin and W. O. McMillan.  (2019) Interplay between developmental flexibility and determinism in the evolution of mimetic Heliconius wing patterns. Current Biology 29 (23):3996-4009. e4.

Doudna, J. A., and Charpentier, E. (2014). Genome editing. The new frontier of genome engineering with CRISPR-Cas9. Science, 346(6213), 1077-1086.

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