Biology subjects

DeNieu, M.

Publications and source records attributed to DeNieu, M..

3 recordsLinked to original sources

bioRxiv2021

Genetic coordination of sperm morphology and seminal fluid proteins promotes male reproductive success in Drosophila melanogaster

Spermatozoal morphology is highly variable both among and within species and in ways that can significantly impact fertilization success. In Drosophila melanogaster, paternity success depends on sperm length of both competing males and length of the females primary sperm storage organ. We found that genes upregulated in long sperm testes are enriched for lncRNAs and seminal fluid proteins (Sfps). Transferred in seminal fluid to the female during mating, Sfps are secreted by the male accessory glands (AG) and affect female remating rate, physiology, and behavior with concomitant advantages for male reproductive success. Despite being upregulated in long sperm testes, they have no known function in testis tissue. We found that Sex Peptide and ovulin (Acp26Aa) knockouts resulted in shorter sperm, suggesting that Sfps may regulate sperm length during spermatogenesis. However, knockout of AG function did not affect sperm length, suggesting that AG expression has no influence on spermatogenic processes. We also found that long sperm males are better able to delay female remating, suggesting higher Sfp expression in AG. These results might suggest that long sperm males have a double advantage in sperm competition by both delaying female remating, likely through transfer of more Sfps, and by resisting sperm displacement. However, we also found that this extra advantage does not necessarily translate to more progeny or higher paternity success. Thus, we found that multiple components of the ejaculate coordinate to promote male reproductive success at different stages of reproduction, but the realized fitness advantages in sperm competition are uncertain. Significance StatementThe ejaculate is comprised of sperm produced in the testis and seminal fluid primarily produced in the male accessory glands (AG). These complementary components are both critical for male reproductive success, but they are largely considered to be functionally, genetically, and developmentally independent. In a quest to understand genetic mechanisms of sperm length variation, we found that genes upregulated in long sperm testes are enriched for lncRNAs and seminal fluid proteins (Sfps). Knockout of two Sfps, Sex Peptide and ovulin, results in shorter sperm, though knockout of AG function has no effect. Moreover, long sperm males delay female remating longer. These results suggest sophisticated testis-AG coordination that amplifies male reproductive success, with implications for evolutionary integration of sexually selected traits.

genetics↗

bioRxiv2019

Two gut microbes are necessary and sufficient for normal cognition in Drosophila melanogaster

It is widely accepted that the gut microbiome can affect various aspects of brain function, including anxiety, depression, learning, and memory. However, we know little about how individual microbial species contribute to communication along the gut-brain axis. Vertebrate microbiomes are comprised of hundreds of species, making it difficult to systematically target individual microbes and their interactions. Here, we use Drosophila melanogaster as a simple model organism to tease apart individual and combined effects of gut microbes on cognition. We used an aversive phototactic suppression assay to show that two dominant gut commensals in our lab stock, Lactobacillus and Acetobacter, are necessary and sufficient for normal learning and short-term memory relative to flies with a conventional microbiome. We also demonstrate that microbes did not affect their hosts ability to detect the aversive learning stimulus (quinine), suggesting that our results were due to decreased cognition and not sensory deficits. We thus establish Drosophila as a model for elucidating mechanisms of gut-brain communication at the level of individual bacterial species.

animal behavior and cognition↗

bioRxiv2017

How Well Do You Know Your Mutation? Complex Effects Of Genetic Background On Expressivity, Complementation, And Ordering Of Allelic Effects

For a given gene, different mutations influence organismal phenotypes to varying degrees. However, the expressivity of these variants not only depends on the DNA lesion associated with the mutation, but also on factors including the genetic background and rearing environment. The degree to which these factors influence related alleles, genes, or pathways similarly, and whether similar developmental mechanisms underlie variation in the expressivity of a single allele across conditions and variation across alleles is poorly understood. Besides their fundamental biological significance, these questions have important implications for the interpretation of functional genetic analyses, for example, if these factors alter the ordering of allelic series or patterns of complementation. We examined the impact of genetic background and rearing environment for a series of mutations spanning the range of phenotypic effects for both the scalloped and vestigial genes, which influence wing development in Drosophila melanogaster. Genetic background and rearing environment influenced the phenotypic outcome of mutations, including intra-genic interactions, particularly for mutations of moderate expressivity. We examined whether cellular correlates (such as cell proliferation during development) of these phenotypic effects matched the observed phenotypic outcome. While cell proliferation decreased with mutations of increasingly severe effects, surprisingly it did not co-vary strongly with the degree of background dependence. We discuss these findings and propose a phenomenological model to aid in understanding the biology of genes, and how this influences our interpretation of allelic effects in genetic analysis.

genetics↗