The aim of the project is to examine the evolution of sex determination across amniotes, a species-rich group, involving lineages with XX/XY, ZZ/ZW or temperature-dependent sex determination. Sex chromosomes evolved from a pair of autosomes, where the emergence of a sex-determining locus triggered gradual structural changes such as accumulation of sexual antagonistic alleles, recombination arrest, accumulation of repeats, loss of functional genes and heterochromatinization. This model represents the classical paradigm for decades. Recently, large variability in sex chromosomes was documented in non-model species, questioning the role of previously assumed evolutionary drivers and other aspects of sex chromosome differentiation. It remains unclear why amniote lineages differ so substantially in the degree of differentiation of sex chromosomes. Using advanced genetic and genomic methods, the PhD candidate will attempt to solve long standing enigmas concerning the role of sexual antagonism, inversions and gene dose regulatory mechanisms in the differentiation rate of sex chromosomes in selected lineages of amniote vertebrates. A previous experience in molecular genetics, cytogenetics and/or bioinformatics (genomics/transcriptomics) is essential for a successful PhD candidate.
Five relevant publications of the research group:
Kostmann A., Kratochvil L., Rovatsos M. (2020). Poorly differentiated XX/XY sex chromosomes are widely shared across skink radiation. Proceedings of the Royal Society B, in press.
Rovatsos M., Gamble T., Nielsen S., Georges A., Ezaz T., Kratochvil L. (2020). Do male and female heterogamety really differ in expression regulation? Lack of global dosage balance in pygopodid geckos. Philosophical Transactions of the Royal Society B, in press.
Rovatsos M., Farkačová K., Altmanová M., Johnson Pokorná M., Kratochvíl L. (2018). The rise and fall of differentiated sex chromosomes: Evolutionary tinkering with mammalian sex chromosomes in geckos. Molecular Ecology 28: 3042-3052.
Rovatsos M., Rehák I., Velenský P., Kratochvíl L. (2019). Shared ancient sex chromosomes in varanids, beaded lizards, and alligator lizards. Molecular Biology and Evolution 36: 1113-1120.
Mazzoleni S., Augstenová B., Clemente L., Auer M., Fritz U., Praschag P., Protiva T., Velenský P., Kratochvíl L., Rovatsos M. (2020). Sex is determined by XX/XY sex chromosomes in Australasian side-necked turtles (Testudines: Chelidae). Scientific Reports 10: 1-11.