Meeting Abstract

68.2  Wednesday, Jan. 6  Waking the beast: identifying candidate genes and pathways for dormancy termination via transcriptome profiling RAGLAND, GJ*; FEDER, JL; BERLOCHER, SH; HAHN, DA; University of Florida; University of Notre Dame; University of Illinois; University of Florida gragland@ufl.edu

Diapause, or dormancy, is a developmentally arrested, stress resistant stage that constitutes a major climatic adaptation common to nearly all insect taxa. The timing of diapause initiation and termination are critically important life history traits that synchronize life cycles with seasonal fluctuations. Further, variation in diapause timing can serve as a potent isolating mechanism, as is the case in speciating host races of the apple maggot fly, Rhagoletis pomonella, that exploit different host fruits at different times of the year. We investigated the mechanistic basis of diapause termination in the apple maggot fly to identify candidate genes and physiological pathways that may influence adaptive differences in timing among native hawthorn and derived apple host races. R. pomonella diapause as pupae, and we used a respirometric assay to sample at developmental landmarks prior to, during, and after diapause termination and resumption of active development. To assess patterns of differential gene expression, we performed competitive hybridizations comparing the developmental landmarks on cDNA microarrays constructed from an extensive EST library. We present results from this experiment, highlighting tests of differential expression in a priori pathways including ecdysone metabolism, stress response, and insulin signaling. We also present a comparative analysis of a similar experiment conducted on diapausing pupae of the flesh fly, focusing on evolutionarily conserved pathways.