NSF PRFB FY23: Polyploidy as a driver of developmental and morphological evolution

Itgen, Michael, Indianapolis IN

Investigators

Abstract

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2023, Integrative Research Investigating the Rules of Life Governing Interactions Between Genomes, Environment, and Phenotypes. The fellowship supports research and training of the fellow that will contribute to the area of Rules of Life in innovative ways. Organismal development results from the actions of expressed genes and cellular processes. Changes in these traits can alter development, and therefore, the size and shape of an organism. Because of this, polyploidization can be a key factor in the evolution of development. An organism becomes a polyploid by having more than two sets of chromosomes. These additional chromosomes have direct effects on cell biology. First, polyploidy can alter gene expression by increasing the number of gene copies. Additionally, cells become larger as a result of the extra DNA content. Yet, how these polyploidy-related changes affect development remains largely mysterious. However, these effects do appear to be responsible for the rarity of polyploid animals. Most animals fail to develop early on as polyploids, suggesting development is sensitive to this condition. By studying polyploid animals, the Fellow aims to uncover the circumstances that make polyploidy possible in some lineages of animals but not others. To achieve this, the Fellow will characterize development in polyploid salamanders. This fellowship will also support undergraduate research and educational outreach. The research aims to investigate the consequences of polyploidy on the evolution of development and morphology in a hybrid lineage of polyploid salamanders (genus Ambystoma). The Fellow will assess how increased cell size due to polyploidy acts as a determinant of morphology across organ systems using CT scan data and histology. Second, the Fellow will investigate how ploidy-related changes in cell size and gene expression alter morphogenesis to characterize developing tissue morphology, pattern formation, and developmental cellular processes using immunohistochemistry and in situ hybridization. Finally, the Fellow will characterize how the additional copies of a genome gained through polyploidization affect developmental gene expression using ATAC-Seq and RNA-Seq to test for differential regulation and expression of developmental genes throughout development. By studying these unique polyploid salamanders, the Fellow aims to understand how polyploidy shapes development and morphology. Addressing these knowledge gaps will broaden the fields’ understanding of the role polyploidization has had in the evolution of phenotypic traits across the tree of life. In addition, the Fellow will facilitate and mentor research opportunities and develop workshops for undergraduates with limited research opportunities. The Fellow will also receive training in skills related to developmental and genomic research. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.