Complications of complexity: integrating environmental, genetic and hormonal control of insect diapause

Emerson, Kevin J.; Bradshaw, William E.; Holzapfel, Christina

doi:10.1016/j.tig.2009.03.009

Cited by 167 publications

(164 citation statements)

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“…Alternatively, if the circadian clock and the photoperiodic timer were controlled by different and independently acting domains within the same gene (gene pleiotropy as in Emerson et al, 2009a), that relationship would CPPs (h) determined from logits; amplitudes of the rhythm from non-linear regression (% pupation). T¼the total duration of light plus dark for each cycle.…”

Section: Discussionmentioning

confidence: 99%

“…Apart from Emerson et al, 2010, all molecular approaches to identifying photoperiodism genes in insects have used known circadian clock genes as candidate loci (Koštál, 2011;Saunders and Bertossa, 2011), but without definitive results (Emerson et al, 2009a;Holzapfel, 2007b, 2010a, b;Schiesari et al, 2011). Because of the historical inertia created by Bünning's (1936) hypothesis, because both circadian rhythmicity and photoperiodism depend primarily on the input of light, and because of the intrinsic appeal of connecting daily with seasonal timing, we believe this trend will continue.…”

Section: Discussionmentioning

confidence: 99%

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Genetic correlations and the evolution of photoperiodic time measurement within a local population of the pitcher-plant mosquito, Wyeomyia smithii

2011

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The genetic relationship between the daily circadian clock and the seasonal photoperiodic timer remains a subject of intense controversy. In Wyeomyia smithii, the critical photoperiod (an overt expression of the photoperiodic timer) evolves independently of the rhythmic response to the Nanda-Hamner protocol (an overt expression of the daily circadian clock) over a wide geographical range in North America. Herein, we focus on these two processes within a single local population in which there is a negative genetic correlation between them. We show that antagonistic selection against this genetic correlation rapidly breaks it down and, in fact, reverses its sign, showing that the genetic correlation is due primarily to linkage and not to pleiotropy. This rapid reversal of the genetic correlation within a small, single population means that it is difficult to argue that circadian rhythmicity forms the necessary, causal basis for the adaptive divergence of photoperiodic time measurement within populations or for the evolution of photoperiodic time measurement among populations over a broad geographical gradient of seasonal selection. Heredity (2012) 108, 473-479; doi:10.1038/hdy.2011.108; published online 9 November 2011Keywords: linkage; pleiotropy; photoperiodism; circadian rhythmicity; antagonistic selection INTRODUCTION Herein we are concerned with the genetic and evolutionary relationship between the photoperiodic timer that serves to organize seasonal events and the circadian clock that serves to organize daily events in the life histories of animals. 'Only model organisms live in a world of endless summer; most organisms in nature confront a seasonal environment. Fitness in a seasonal environment involves the abilities to exploit the favorable season, to avoid or mitigate the effects of the unfavorable season, and to make a timely transition between the two lifestyles' (Bradshaw et al., 2004). Timing is of the essence. Organisms cannot wait for the onset of winter but must have physiological mechanisms that enable them to prepare for the winter in advance. A wide variety of animals from rotifers to rodents use the length of the day (photoperiod) as an anticipatory cue in preparation for the changing seasons. Examples include the use of day length to cue the seasonal timing of migration in birds, to cue the seasonal timing of reproduction in mammals, and to cue the seasonal timing of diapause (dormancy) in arthropods (Bradshaw and Holzapfel, 2007a). Photoperiodic response is typically determined by exposing animals to a range of day lengths and plotting percent response as a function of hours of light per day to which they were exposed (Figure 1a). Photoperiodic response curves are usually sigmoid in shape and the day length that promotes a response in 50% of a sample population defines the critical photoperiod (hereafter, CPP) that is used as a proxy for the photoperiodic response curve.For more than 75 years, it has been hypothesized that the causal basis of the seasonal photoperiodic timer is controlled by ...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Genetic correlations and the evolution of photoperiodic time measurement within a local population of the pitcher-plant mosquito, Wyeomyia smithii

2011

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“…As a consequence, it helps the species survive extreme forms of stress (e.g., drought) and it also “times” the birth of offspring to a more favorable environment (e.g., rainy season). In nature, diapause phenomena are widespread throughout the animal kingdom, from simple organisms such as brine shrimps and silkworms, to mammals such as the roe deer, bats, and mice (Bleier, 1975; Emerson, Bradshaw & Holzapfel, 2009; Hand, Denlinger, Podrabsky & Roy, 2016; Lambert et al., 2001; Lopes, Desmarais & Murphy, 2004; Meenakumari & Krishna, 2005; Ptak et al., 2012; Sato et al., 2014; Schiesari & O'Connor, 2013; Sim & Denlinger, 2013). Our current knowledge of diapause has benefited greatly from the studies in invertebrates.…”

Section: Using the African Turquoise Killifish As A Research Organismmentioning

confidence: 99%

The African turquoise killifish: A research organism to study vertebrate aging and diapause

Brunet²

2018

Aging Cell

132

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SummaryThe African turquoise killifish has recently gained significant traction as a new research organism in the aging field. Our understanding of aging has strongly benefited from canonical research organisms—yeast, C. elegans, Drosophila, zebrafish, and mice. Many characteristics that are essential to understand aging—for example, the adaptive immune system or the hypothalamo‐pituitary axis—are only present in vertebrates (zebrafish and mice). However, zebrafish and mice live more than 3 years and their relatively long lifespans are not compatible with high‐throughput studies. Therefore, the turquoise killifish, a vertebrate with a naturally compressed lifespan of only 4–6 months, fills an essential gap to understand aging. With a recently developed genomic and genetic toolkit, the turquoise killifish not only provides practical advantages for lifespan and longitudinal experiments, but also allows more systematic characterizations of the interplay between genetics and environment during vertebrate aging. Interestingly, the turquoise killifish can also enter a long‐term dormant state during development called diapause. Killifish embryos in diapause already have some organs and tissues, and they can last in this state for years, exhibiting exceptional resistance to stress and to damages due to the passage of time. Understanding the diapause state could give new insights into strategies to prevent the damage caused by aging and to better preserve organs, tissues, and cells. Thus, the African turquoise killifish brings two interesting aspects to the aging field—a compressed lifespan and a long‐term resistant diapause state, both of which should spark new discoveries in the field.

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“…It is indeed fortunate that such a genetically tractable organism also shows a photoperiodic reproductive diapauses in females, albeit a shallow one, at least in European populations [7,138]. In fact, in D. melanogaster the photoperiod modulates reproductive diapause within a 10-13°C range of permissiveness temperature.…”

Section: Circadian Signalling and Diapause: What Is The Link?mentioning

confidence: 99%

The hormonal and circadian basis for insect photoperiodic timing

2011

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Edited by Martha Merrow and Michael BrunnerKeywords: Insects Photoperiodism Diapause Endocrine axis Circadian clock Clock genes a b s t r a c t Daylength perception in temperate zones is a critical feature of insect life histories, and leads to developmental changes for resisting unfavourable seasons. The role of the neuroendocrine axis in the photoperiodic response of insects is discussed in relation to the key organs and molecules that are involved. We also discuss the controversial issue of the possible involvement of the circadian clock in photoperiodicity. Drosophila melanogaster has a shallow photoperiodic response that leads to reproductive arrest in adults, yet the unrivalled molecular genetic toolkit available for this model insect should allow the systematic molecular and neurobiological dissection of this complex phenotype.

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Complications of complexity: integrating environmental, genetic and hormonal control of insect diapause

Cited by 167 publications

References 68 publications

Genetic correlations and the evolution of photoperiodic time measurement within a local population of the pitcher-plant mosquito, Wyeomyia smithii

Genetic correlations and the evolution of photoperiodic time measurement within a local population of the pitcher-plant mosquito, Wyeomyia smithii

The African turquoise killifish: A research organism to study vertebrate aging and diapause

The hormonal and circadian basis for insect photoperiodic timing

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