Identifying the mechanisms of phenotypic robustness using fluctuating asymmetry

Phenotypic robustness, the capacity for organisms to buffer their development against internal and external perturbations, controls the strength of the links between phenotypes, genotypes, and environments.

Despite its importance linking scales of biological organization, we have a poor understanding of how phenotypic robustness worksfor example, the degree to which it is heritable, if the same mechanisms control both intrinsic and extrinsic robustness, or if it is correlated across organ systems. Working with Dr.

Claudius Kratochwil in the Integrated Evolutionary Biology group at the University of Helsinki (UH), Finland, I will investigate the mechanisms of robustness using fluctuating asymmetry as an indicator of robustness.

I will take advantage an ongoing hybrid cross of cichlid fishes in the lab, the offspring of which exhibit increasing rates of left-right color pattern asymmetry compared to their symmetrical parents.

In research objective O1, I will identify the genomic basis of phenotypic robustness by selecting for increased and decreased color pattern asymmetry in this hybrid cross, and use whole genome sequencing to identify loci associated with decreased symmetry.

In O2, I will test for gene-environment interactions in robustness by raising fish from asymmetrical and symmetrical populations at high and low temperatures and testing whether these populations exhibit different reaction norms.

In O3, I will test whether robustness is correlated across organ systems by measuring asymmetry in other traits (paired fins, gills, jaws, eyes, and lateral line neuromasts) in the most and least asymmetrical fish from the cross. I will ask whether selecting for asymmetry in color patterns has also increased asymmetry in these traits.