Speaker: Heather Jamniczky
Abstract. Natural selection acts on phenotypic variation, but evolutionary change occurs at the level of the genotype. Genotype and phenotype are linked by organismal development in a complex and highly structured fashion, such that developmental processes have a substantial effect on the evolvability of complex phenotypes. Understanding this developmental basis for evolvability is the central question of evolutionary developmental biology. Our research makes extensive use of the techniques of landmark-based three-dimensional geometric morphometrics as we seek to quantify phenotypic variation in response to genetic and developmental perturbation. These techniques are limited by the ability to place homologous landmarks repeatably and reliably across a large sample of specimens. As we delve deeper into the relationship between genotype and phenotype, we find these methods to be insufficient for the quantification and comparison of a number of structures of interest. Three current avenues of active research interest for our group include the study of branching structures, the study of gene and protein expression patterns in developing organisms, and the study of interactions among tissues in developing organisms. In the first case, the challenge is to find a means by which shape variation in a branching structure, such as a circulatory tree, may be quantitatively compared to variation in both other branching structures as well as in non-branching structures, such as skulls. In the second case, the challenge is to find a means by which shape variation in an irregular, amorphous patch of gene or protein expression within a tissue can be compared to other such patches, and to the shape of the structure in which it resides. In the third case, the challenge is similar to the previous one, where wish to compare irregular shapes to each other as both change over developmental time. We seek to develop methodologies by which we can begin to explore the developmental basis for evolvability as it pertains to instances such as these.