Mid-day siesta in natural populations of D. melanogaster from Africa exhibits an altitudinal cline and is regulated by splicing of a thermosensitive intron in the period clock geneReport as inadecuate




Mid-day siesta in natural populations of D. melanogaster from Africa exhibits an altitudinal cline and is regulated by splicing of a thermosensitive intron in the period clock gene - Download this document for free, or read online. Document in PDF available to download.

BMC Evolutionary Biology

, 17:32

Evolutionary ecology and behaviour

Abstract

BackgroundMany diurnal animals exhibit a mid-day ‘siesta’, generally thought to be an adaptive response aimed at minimizing exposure to heat on warm days, suggesting that in regions with cooler climates mid-day siestas might be a less prominent feature of animal behavior. Drosophila melanogaster exhibits thermal plasticity in its mid-day siesta that is partly governed by the thermosensitive splicing of the 3’-terminal intron termed dmpi8 from the key circadian clock gene period per. For example, decreases in temperature lead to progressively more efficient splicing, which increasingly favors activity over sleep during the mid-day. In this study we sought to determine if the adaptation of D. melanogaster from its ancestral range in the lowlands of tropical Africa to the cooler temperatures found at high altitudes involved changes in mid-day sleep behavior and-or dmpi8 splicing efficiency.

ResultsUsing natural populations of Drosophila melanogaster from different altitudes in tropical Africa we show that flies from high elevations have a reduced mid-day siesta and less consolidated sleep. We identified a single nucleotide polymorphism SNP in the per 3’ untranslated region that has strong effects on dmpi8 splicing and mid-day sleep levels in both low and high altitude flies. Intriguingly, high altitude flies with a particular variant of this SNP exhibit increased dmpi8 splicing efficiency compared to their low altitude counterparts, consistent with reduced mid-day siesta. Thus, a boost in dmpi8 splicing efficiency appears to have played a prominent but not universal role in how African flies adapted to the cooler temperatures at high altitude.

ConclusionsOur findings point towards mid-day sleep behavior as a key evolutionary target in the thermal adaptation of animals, and provide a genetic framework for investigating daytime sleep in diurnal animals which appears to be driven by mechanisms distinct from those underlying nighttime sleep.

KeywordsDrosophila Sleep Circadian Temperature Mid-day siesta Splicing Altitude Thermal adaptation dmpi8 intron Period gene AbbreviationsCTCircadian time hr

DDContinuous dark

dmpi8Drosophila melanogaster period gene intron 8

LD12 h-12 h light–dark cycle

LLContinuous light

MSBLMean sleep bout length

ZTZeitgeber time hr

Electronic supplementary materialThe online version of this article doi:10.1186-s12862-017-0880-8 contains supplementary material, which is available to authorized users.

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Author: Weihuan Cao - Isaac Edery

Source: https://link.springer.com/



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