Neo-sex chromosome evolution: molecular mechanisms and evolutionary consequences of nascent sex chromosomes

Sex chromosomes arose independently several times in evolution from ordinary autosomal pairs by acquiring a sex determining region, followed by recombination suppression, accumulation of repeats and degeneration of genes.

Despite much theoretical and empirical work to explain the convergent evolution of sex chromosomes across eukaryotes, we severely lack a detailed molecular view of how and what kind of sex-chromosomal changes occur over various evolutionary time scales.

Addressing these fundamental gaps in our knowledge requires the study of young sex chromosome systems that differ among closely related species.

Here, I propose to investigate the early signature of sex chromosome evolution using three pairs of ancestral XO and derived neo-XY chromosomal races in the morabine grasshopper Vandiemenella viatica species complex.

By using male and female genomes, transcriptomes and cytognetic, I will investigate sex-chromosome evolution by exploring both the molecular mechanisms that underlie these events and the consequences of recombination suppression on the process of sex-chromosome differentiation. The 4-year project will start in 2021 and end in 2024.

The investigation of the sex chromosome diversity found within V. viatica will explicitly test several key theories in the evolution of sex chromosomes and shed light on temporal sequence of molecular evolution by the formation of neo-sex chromosomes.