The Molecular Basis of Coadaptation and Hybrid Breakdown

University Of California-San Diego Scripps Inst Of Oceanography, La Jolla CA

Investigators

Abstract

When animals or plants from genetically divergent populations interbreed, the resulting hybrids often show reduced performance (hybrid breakdown) relative to their parents. This is especially true in second generation (F2) hybrids, where incompatible genotypes may arise via recombination. The proposed work uses the marine copepod Tigriopus californicus as a model system for analyses of the molecular mechanisms underlying hybrid breakdown. This project has two parts. In the first, experiments focus on interactions between nuclear and mitochondrial genes, testing the hypothesis that hybridization disrupts energy production in mitochondria. The second part of the study tests the hypothesis that hybridization disrupts transcription of rRNA genes and this results in reduced rates of protein synthesis (and reduced performance) in hybrids. Hybrid breakdown is widespread in nature and has important ramifications in medicine, agriculture and conservation biology. Results from this project may aid in understanding: (1) the growing number of human diseases known to be associated with mtDNA and nuclear gene mutations which disrupt mitochondrial function, (2) the role of gene interactions in agriculture, where vigorous F1 hybrid strains often give rise to poor-performing F2 hybrids, and (3) the extent to which wildlife management and conservation practices should restrict movement of organisms among geographic locales. The project will also provide excellent training opportunities for undergraduate, graduate and postdoctoral researchers.