Gene-by-Temperature Interactions and Candidate Plasticity Genes for Morphological Traits in Drosophila melanogaster

Abstract

Understanding the genetic architecture of any quantitative trait requires identifying the genes involved in its expression in different environmental conditions. This goal can be achieved by mutagenesis screens in genetically tractable model organisms such as Drosophila melanogaster. Temperature during ontogenesis is an important environmental factor affecting development and phenotypic variation in holometabolous insects. In spite of the importance of phenotypic plasticity and genotype by environment interaction (GEI) for fitness related traits, its genetic basis has remained elusive. In this context, we analyzed five different adult morphological traits (face width, head width, thorax length, wing size and wing shape) in 42 co-isogenic single P-element insertional lines of Drosophila melanogaster raised at 17°C and 25°C. Our analyses showed that all lines differed from the control for at least one trait in males or females at either temperature. However, no line showed those differences for all traits in both sexes and temperatures simultaneously. In this sense, the most pleiotropic candidate genes were CG34460, Lsd-2 and Spn. Our analyses also revealed extensive genetic variation for all the characters mostly indicated by strong GEIs. Further, our results indicate that GEIs were predominantly explained by changes in ranking order in all cases suggesting that a moderate number of genes are involved in the expression of each character at both temperatures. Most lines displayed a plastic response for at least one trait in either sex. In this regard, P-element insertions affecting plasticity of a large number of traits were associated to the candidate genes Btk29A, CG43340, Drak and jim. Further studies will help to elucidate the relevance of these genes on the morphogenesis of different body structures in natural populations of D. melanogaster.

A new approach for investigating venom function applied to venom calreticulin in a parasitoid wasp

“…Venom calreticulin down-regulates an imaginal disc-derived wing morphogenesis gene, known to be involved in developmental timing in a temperature-independent manner in Drosophila (Carreira et al, 2013; Mensch et al, 2008), and which may play a role in wing sexual dimorphism in Diptera (Carreira et al, 2011). Finally, a non-specific DNA/RNA endonuclease is also down-regulated by calreticulin.…”

Life-History Evolution and the Genetics of Fitness Components inDrosophila melanogaster

“…Thermal plasticity of gene expression ("transcriptional plasticity") has also been studied, for example in the context of population-level plasticity, thermal reaction norms and GxE (Zhou et al 2012;Carreira et al 2013;Chen et al 2015), fluctuating temperatures (Sørensen et al 2016), and latitudinal clines [Levine et al 2011;Chen et al 2012;Zhao et al 2016;Porcelli et al 2016 (D. subobscura); Clemson et al 2016). Such studies can be informative about the mechanisms underlying thermal life-history plasticity.…”

Genotype‐by‐environment interactions underlie the expression of pre‐ and post‐copulatory sexually selected traits in guppies

“…Despite these important evolutionary implications, there are relatively few studies that document GEIs in the context of sexual selection, particularly those revealing ecological crossovers among reaction norms (i.e. changes in the rank performance of genotypes between environments; Lewis et al ., ; Carreira et al ., ; Ingleby et al ., ) and/or changes in patterns of genetic covariance in different environments (Robinson et al ., ).…”