Biology subjects

Pischedda, A.

Publications and source records attributed to Pischedda, A..

3 recordsLinked to original sources

bioRxiv2024

Genetic variation in male mate choice for large females in Drosophila melanogaster

Males in many species show courtship and mating preferences for certain females over others when given the choice. One of the most common targets of male mate choice in insects is female body size, with males preferring to court and mate with larger, higher-fecundity females and investing more resources in matings with those females. Although this preference is well-documented at the species level, less is known about how this preference varies within species and whether there is standing genetic variation for male mate choice within populations. We used hemiclonal analysis in the fruit fly, Drosophila melanogaster, to test for heritable genetic variation in pre- and post-copulatory components of male mate choice for large females. We found additive genetic variation for both forms of male choice: males from different hemiclone lines varied in the strength of their courtship preferences for large females and the degree to which they extended matings with large females. Although males from hemiclone lines with stronger courtship preferences for large females were more likely to mate with those females, there was no genetic correlation between pre- and post-copulatory components of male mate choice, suggesting that they are under independent genetic control. Genetic variation in male mate choice may be widespread, potentially impacting the fitness of both sexes and the adaptive evolution of populations.

evolutionary biology↗

bioRxiv2019

The genetics of male pheromone preference difference between Drosophila melanogaster and D. simulans

Species of flies in the genus Drosophila differ dramatically in their preferences for mates, but little is known about the genetic or neurological underpinnings of this evolution. Recent advances have been made to our understanding of one case: pheromone preference evolution between the species D. melanogaster and D. simulans. Males of both species are very sensitive to the pheromone 7,11-HD that is present only on the cuticle of female D. melanogaster. In one species this cue activates courtship, and in the other it represses it. This change in valence was recently shown to result from the modification of central processing neurons, rather than changes in peripherally expressed receptors, but nothing is known about the genetic changes that are responsible. In the current study, we show that a 1.35 Mb locus on the X chromosome has a major effect on male 7,11-HD preference. Unfortunately, when this locus is divided, the effect is largely lost. We instead attempt to filter the 159 genes within this region using our newfound understanding of the neuronal underpinnings of this phenotype to identify and test candidate genes. We present the results of these tests, and discuss the difficulty of identifying the genetic architecture of behavioral traits and the potential of connecting these genetic changes to the neuronal modifications that elicit different behaviors.

genetics↗

bioRxiv2018

The loci of behavioral evolution: Fas2 and tilB underlie differences in pupation site choice behavior between Drosophila melanogaster and D. simulans

The recent boom in genotype-phenotype studies has led to a greater understanding of the genetic architecture of a variety of traits. Among these traits, however, behaviors are still lacking, perhaps because they are complex and environmentally sensitive phenotypes, making them difficult to measure reliably for association studies. Here, we aim to fill this gap in knowledge with the results of a genetic screen for a complex behavioral difference, pupation site choice, between Drosophila melanogaster and D. simulans. In this study, we demonstrate a significant contribution of the X chromosome to the difference in pupation site choice behavior between these species. Using a panel of X-chromosome deletions, we screened the majority of the X chromosome for causal loci, and identified two regions that explain a large proportion of the X-effect. We then used gene disruptions and RNAi to demonstrate the substantial effects of a single gene within each region: Fas2 and tilB. Finally, we show that differences in tilB expression underlie species differences in pupation site choice behavior, and that generally, pupation site choice behavior appears to be correlated with relative expression of this gene. Our results suggest that even complex, environmentally sensitive behaviors may evolve through changes to loci with large phenotypic effects.\n\nAuthor summaryBehaviors are complex traits that involve sensory detection, higher level processing, and a coordinated output by the nervous system. This level of processing is highly susceptible to environmentally induced variation. Because of their complexity and sensitivity, behaviors are difficult to study; as a result, we have very little understanding of the genes involved in behavioral variation. In this study, we use common laboratory fruit fly model, Drosophila, to address this gap and dissect the genetic underpinnings of an environmentally sensitive behavior that differs between species. We find that a significant amount of the phenotypic difference between species is explained by a single chromosome. We further show that just two genes on this chromosome account for a large majority of its effect, suggesting that the genetic basis of complex behavioral evolution may be simpler than anticipated. For one of these genes, we show that a species-level difference in gene expression is associated with the difference in behavior. Our results contribute to a growing number of studies identifying the genetic components of behavior. Ultimately, we hope to use these data to better predict the number, types, and effects of genetic mutations necessary for complex behaviors to evolve.

genetics↗