2020/12/16 by Guanxiong Yan, Wentao Yang, Xiaojie Han +5 · 1 voice · 1 citation
Biochemistry, Genetics and Molecular Biology · Agricultural and Biological Sciences · #Protist diversity and phylogeny #Chromosomal and Genetic Variations #Genomics and Phylogenetic Studies
paper · pdf · doi:10.1016/j.isci.2020.101950
openalex publication_date 2020/12/16 · openalex created_date 2020/12/21 · openalex updated_date 2026/07/28
The multiple mating type system of the Ciliate Tetrahymena thermophila is a self/non-self recognition system, whose specificity resides in a head-to-head, functionally distinct pair of genes, MTA and MTB . We have now sequenced and analyzed these mating type genes in nine additional Tetrahymena species. We conclude that MTA and MTB are derived from a common ancestral gene and have co-evolved for at least ∼150 Myr. We show that T. shanghaiensis , a perpetual selfer (unisexual) species, has a single mating type gene pair, whose MTA and MTB genes likely have different mating type specificity. We document the recent replacement of a complete different set of mating type specificities for another, illustrating how quickly this can happen. We discuss how varying conditions of reproductive stress could result in evolutionary co-adaptations of MTA and MTB genes and changes in mating type determination mechanisms.