My research focuses on the study of genome evolution in the grasshopper Vandiemenella viatica species complex, particularly sex chromosomes and repetitive DNA using comparative genomics, molecular biology and cytogenetics. While most of the viatica species have X0 system, where females have two X chromosomes and males only one, there has been repeated and independent chromosomal fusions between the ancestral X0 races and autosomes resulting in the formation of new Y chromosomes (males neo-XY and females neo-XX). This allows independent comparisons between pairs of races with different combinations of autosome-X chromosome fusions to investigate the timing and patterns of recombination suppression, gene loss, gene expression differentiation, and genome divergence.
Sex is a fundamental and ancient feature of eukaryotic reproduction often associated with the presence of specialized sex chromosomes involved in female or male development. Despite the importance and conservation of sexual reproduction, there is a notable diversity of sex chromosomes within and between sexes: XY system with female XX and male XY, and ZW system with female ZW and male ZZ. This diversity is likely to have key consequences for multiple facets of evolution, as sex chromosomes play central roles in adaptation, speciation and sexual dimorphism but remains unclear how sex chromosomes are built and what kind of sex-specific changes occur. Understanding the causes and consequences of sex chromosome evolution requires study systems where sex chromosomes have evolved recently and independently several times. My current research involve the understanding of the early signatures of sex chromosome evolution using the grasshopper Vandiemenella viatica species complex. While most species have and X0 system, where females have two X chromosomes and males only one, there has been repeated and independent chromosomal fusions between the ancestral X and autosomes resulting in the formation of new Y chromosomes. By combining state-of-the art genomics, transcriptomics, single cell resolution, and cytogenetics, we seek to provide an integrated understanding of the early signatures of sex chromosome evolution. The research aims to answer three key questions:
- How is recombination suppressed between nascent sex chromosomes?
- How does gene regulation evolve after recombination suppression?
- How fast does the neo-Y degenerate after recombination suppression?