Abstract: The recent release of sequences of several unexplored yeast species which cover an evolutionary range comparable to the entire phylum of chordates, offers us a unique opportunity to investigate how genes involved in adaptation have been shaped by evolution. We have examined how three different sets of genes, all related to adaptative processes at the genomic level, have evolved in hemiascomycetes: i) the mating types genes which govern sexuality; ii) the silencing genes which are connected to regulation of mating type cassettes and to Telomere Position Effect; iii) the gene families found repeated in subtelomeric regions. We report new combinations of mating type genes and cassettes in hemiascomycetous species; we show that silencing proteins diverge rapidly. We have also found that in all species studied, subtelomeric gene families exist and are specific to each species.