Sunday, May 18, 2025
5/18/2025
Phenotypic and adaptive consequences of chromosomal rearrangements - Summary: Recent advances in genomic methods have made it possible to characterize the genes and even mutations contributing to adaptation in a variety of organisms. However, most of our knowledge of genetics falls short of pinpointing causal variants in sets of point mutations, and we have mounting evidence that chromosomal rearrangements, that is structural variants (SVs), such as deletions, duplications, inversions and translocations, play a major role in trait variation and adaptive evolution. The research projects outlined in this proposal will investigate the contribution of SVs to trait variation and adaptation in three insect systems: Timema stick insects, Callosobruchus maculatus seed beetles, and Lycaeides butterflies. The overarching questions to be addressed are: How common are different types of SVs? How do they affect trait variation? And what processes maintain SVs in natural populations? Answering these questions will immediately advance our understanding of the material basis of adaptive evolution and has longer-term implications for understanding trait variation in diverse organisms, including humans. Previous work in my lab implicated SVs in (i) the evolution of cryptic coloration and host use in Timema stick insects, (ii) rapid adaptation to a low-quality host plant, lentil, in C. maculatus seed beetles, and (iii) hybrid fitness in Lycaeides butterflies. Proposed work in each system will combine multiple chromosome-level phased genome assemblies, population genomic data, and computational modeling to build on past results and elucidate the general importance and evolutionary history of SVs in these systems. In Timema, work will focus on the evolutionary history of the diverse SVs associated with color and color pattern in different populations and species, and on the phenotypic and adaptive relevance of genome-wide SVs. Proposed work in C. maculatus will shed additional light on the reuse of SVs by determining whether the same SVs confer adaptation to the same and different hosts in geographically distinct populations, and whether these same SVs affect fitness in hybrid beetle populations. In Lycaeides, planned projects will elucidate processes driving contemporary evolution of SVs and connect these SVs to trait variation and fitness in current and ancient hybrids. Overall, this research program will provide a comprehensive assessment of the importance of SVs for trait variation and adaptation across diverse systems that span different time scales (several generations to millions of years) and contexts (cryptic coloration, host use, contemporary evolution and hybrid fitness). By identifying the mechanisms responsible for the maintenance of SV polymorphisms within populations and species, this work has broader implications for understanding the genetic basis of adaptive evolu- tion. Additionally, insights gained from this research could inform our understanding of the genetics and evolution of human health, given the relevance of SVs in human genomics and disease-related traits.
HHS’ Tracking Accountability in Government Grants System (TAGGS) website provides access to detailed descriptions of grants, loans, aggregated direct payments and other types of financial assistance awarded by the HHS Operating Divisions (OPDIVs) and the Office of the Secretary Staff Divisions (STAFFDIVs).