Identification of polymorphic duplications in Drosophila evolving under haploid selection in the spermatogenesis

• Grant number: 22/14620-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: September 01, 2023
• End date: August 31, 2025
• Field of knowledge: Biological Sciences - Genetics - Animal Genetics
• Principal Investigator: Maria Dulcetti Vibranovski
• Grantee: Maryanna Cristiano Simão
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

ew genes are a major source of novelties and show elevated testis expression in different taxa.Studies have shown that new genes evolve by adaptive changes and, therefore, can quickly assumecritical roles in developmental pathways, by producing essential structures. Our group hasdiscovered that new genes are more often expressed in later phases (haploid) of Drosophilaspermatogenesis. We proposed that natural selection in haploid cells elucidates several aspects ofthe origin of new genes by explaining the general prevalence of their testis expression and aparsimonious solution for new alleles to avoid being lost by genetic drift or pseudogenization. Asemerging adaptive mutations would be fixed faster if their phenotypes were expressed by haploidrather than diploid genotypes, new genes bearing advantageous function during this unique stageof development have more chance to become fixed. Using expression data in Drosophilaspermatogenesis, gene age and positive selection signal, we analyzed the genomic pattern of thehaploid selection model, confirming its main predictions. In order to detect haploid selection takingplace in nature, this project aims to use transcriptome data, cell biology, fertility and fitness teststo identify new genes in polymorphic stages associated with expression in later phases ofspermatogenesis. We will take advantage of duplications found to be segregating in Drosophilamelanogaster natural populations expressed in testis and displaying signature of positive selection. (AU)