Localization of quantitative trait loci for diapause and other photoperiodically regulated life history traits important in adaptation to seasonally varying environments

Abstract

Seasonally changing environments at high latitudes present great challenges for the reproduction and survival of insects, and photoperiodic cues play an important role in helping them to synchronize their life cycle with prevalent and forthcoming conditions. We have mapped quantitative trait loci (QTL) responsible for the photoperiodic regulation of four life history traits, female reproductive diapause, cold tolerance, egg-to-eclosion development time and juvenile body weight in Drosophila montana strains from different latitudes in Canada and Finland. The F2 progeny of the cross was reared under a single photoperiod (LD cycle 16:8), which the flies from the Canadian population interpret as early summer and the flies from the Finnish population as late summer. The analysis revealed a unique QTL for diapause induction on the X chromosome and several QTL for this and the other measured traits on the 4th chromosome. Flies' cold tolerance, egg-to-eclosion development time and juvenile body weight had several QTL also on the 2nd, 3rd and 5th chromosome, some of the peaks overlapping with each other. These results suggest that while the downstream output of females' photoperiodic diapause response is partly under a different genetic control from that of the other traits in the given day length, all traits also share some QTL, possibly involving genes with pleiotropic effects and/or multiple tightly linked genes. Nonoverlapping QTL detected for some of the traits also suggest that the traits are potentially capable of independent evolution, even though this may be restricted by epistatic interactions and/or correlations and trade-offs between the traits.

Inter and Intraspecific Genomic Divergence in Drosophila montana Shows Evidence for Cold Adaptation

“…Interestingly, conspecific D. montana populations have been shown to diverge in traits that play a role in ecological adaptation (e.g., Lankinen et al. 2013 ; Tyukmaeva et al. 2015 ), male sexual cues and female preferences (e.g., Klappert et al.…”

“…Information on potential candidate genomic regions and genes for traits involved in cold adaptation and sexual selection has been accumulated through QTL ( Schäfer et al. 2010 ; Tyukmaeva et al. 2015 ), microarray ( Vesala et al.…”

Correlations of Genotype with Climate Parameters Suggest Caenorhabditis elegans Niche Adaptations

“…Machado et al (2016) performed a longitudinal study of Drosophila collected at differing latitudes during a two year time span and compared physiological traits of two different species: D. melanogaster and D. simulans . Other studies have gone further by identifying quantitative trait loci (QTL) for body size and cold tolerance traits involved in adaptation to seasonally varying environments (Tyukmaeva et al 2015; Hangartner et al 2015). Gerken et al (2015) found substantial heritable variation in both short-term and long-term acclimation.…”

Diapause research in insects: historical review and recent work perspectives

“…Genetic basis of diapause expression in insects is emerging as an important facet of recent studies on seasonal polyphenism. Key molecular processes governing diapause have been identified in numerous species from various clades (e.g., Mori et al, 2007;Tyukmaeva et al, 2015;Zhao et al, 2016). The regulation of seasonal photoperiodism is strongly related to the system governing circadian rhythms in insects (B€ unning, 1960;Goto, 2013;Dolezel, 2015).…”