This research concerns the type of gene action responsible for genetic differences among populations of Chamaecrista fasciculata. Genes may act independently of one another so that genetic divergence may simply reflect the accumulated effects of selection acting on single genes. However, important differences among organisms may reflect selection on combinations of genes implying that gene interaction or epistasis is important. The type of gene action can be determined by following the survivorship and reproduction of progeny derived from crosses between populations. If populations are adapted to their environment because selection has acted on combinations of genes, then mixing genes from different populations will result in a disruption of favorable gene interactions and decreased survivorship and reproduction in the hybrid progeny. This study will use traditional biometrical techniques along with molecular analyses to quantify the nature of gene action responsible for adaptation of a population to its environment.
This project has important implications for evolution, crop and animal breeding, and conservation biology. If organisms are adapted to their environment because of interactions among genes, then our models of evolution will need to be more complex. Detection of important gene interaction will provide us with a microevolutionary equivalent of macroevolutionary processes such as speciation. Gene interactions imply that different breeding strategies than those presently employed may have greater efficacy for crop and animal improvement. Strategies for maintaining or preserving genetic diversity in endangered species will be influenced by whether gene interaction determines traits associated with survivorship and reproduction.
