Period and Clock as Candidate Genes for Pdd, a Major Factor of Voltinism Differences in the European corn borer, Ostrinia nubilalis
Oh, Jessica S.
- Closely related races, strains, or species form the foundation of speciation research. In the European corn borer moth (Ostrinia nubilalis), closely related strains are characterized by differences in sex pheromone communication and voltinism (generations per year), both of which contribute to reproductive isolation and the speciation process. Previous studies found that a molecular marker on the ... read moresex (Z) chromosome, Tpi, exhibits significant allelic differentiation between strains. Evolutionary theory predicts such patterns at genome regions harboring loci for reproductive isolation. Indeed, Tpi is closely linked to Pdd, a gene or set of genes that affect postdiapause development time (PDD), a major factor of voltinism. Based on the genome of Bombyx mori (silkmoth), two genes, Period and Clock, were identified as potential candidates for the Pdd gene. To determine the molecular basis for postdiapause development time, the inheritance patterns of PDD and the genotypes of Period and Clock were determined. Genotyping results showed that both Period and Clock genes are candidates for differences in the PDD phenotype, as very few recombinants were discovered. However, a genealogical analysis of Clock revealed no allelic differentiation between different voltine populations, suggesting that the causal locus for PDD is found elsewhere on the Z chromosome. Nevertheless, genetic variation at both Clock and Period may have important consequences for the extent of gene flow between populations.read less