Natural Genetic Variation and Candidate Genes for Morphological Traits in Drosophila melanogaster

CARREIRA, V. P.; MENSCH, J.; HASSON, E.; FANARA, J. J.

PLOS ONE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2016

1932-6203

Body size is a complex character associated to several fitness related traits that vary withinand between species as a consequence of environmental and genetic factors. Latitudinaland altitudinal clines for different morphological traits have been described in several species of Drosophila and previous work identified genomic regions associated with suchvariation in D. melanogaster. However, the genetic factors that orchestrate morphologicalvariation have been barely studied. Here, our main objective was to investigate genetic variation for different morphological traits associated to the second chromosome in natural populations of D. melanogaster along latitudinal and altitudinal gradients in Argentina. Ourresults revealed weak clinal signals and a strong population effect on morphological variation. Moreover, most pairwise comparisons between populations were significant. Ourstudy also showed important within-population genetic variation, which must be associatedto the second chromosome, as the lines are otherwise genetically identical. Next, we examined the contribution of different candidate genes to natural variation for these traits. We performed quantitative complementation tests using a battery of lines bearing mutated alleles at candidate genes located in the second chromosome and six second chromosome substitution lines derived from natural populations which exhibited divergent phenotypes. Results of complementation tests revealed that natural variation at all candidate genes studied, invected, Fasciclin 3, toucan, Reticulon-like1, jing and CG14478, affects the studied characters, suggesting that they are Quantitative Trait Genes for morphological traits. Finally, the phenotypic patterns observed suggest that different alleles of each gene might contribute to natural variation for morphological traits. However, non-additive effects cannot be ruled out, as wild-derived strains differ at myriads of second chromosome loci that may interact epistatically with mutant alleles.