9629081 Via A basic process generating biological diversity is speciation, when populations of one species diverge and eventually become separate species. The genetic changes that produce population divergence and speciation are poorly known. The goal of this project is to determine the number and effects of genes that influence divergence between populations of a single insect species, pea aphid, that infests two host plants. Pea aphid populations on alfalfa and clover are highly genetically divergent and significantly isolated due to habitat choice, and so appear to be incipient species. Quantitative trait loci (QTLs) influencing host plant choice and survival and fertility on each host plant will be mapped on chromosomes using molecular linkage map analysis, as well as biometrical analyses. Studying the genetic basis for speciation is fundamental for understanding the generation of species biodiversity. It is also useful for understanding how pests adapt to new hosts, and how much gene flow there can be between related pest species.
