The evolutionary history of Saccharomyces species inferred fromcompleted mitochondrial genomes and revision in the ‘yeast mitochondrial genetic code’

Sulo, P.aSzabóová, D.a, Bielik, P.aPoláková, S.a,eSoltys, K.bJatzová, K.a, Szemes, T.b,c,d

aDepartment of Biochemistry, Faculty of Natural Sciences, Comenius University, Bratislava, 842 15, Slovakia
bComenius University Science Park, Bratislava, 841 04, Slovakia
cDepartment of Molecular Biology, Faculty of Natural Sciences, Comenius University, Bratislava, 842 15, Slovakia
dGeneton S.r.o., Galvaniho 7, Bratislava, 821 04, Slovakia
eDepartment of Membrane Biochemistry, Centre of Biosciences, Slovak Academy of Sciences, Bratislava, 84005, Slovakia

Abstract

The yeast Saccharomyces are widely used to test ecological and evolutionary hypotheses. A large number of nuclear genomic DNA sequences are available, but mitochondrial genomic data are insufficient. We completed mitochondrial DNA (mtDNA) sequencing from Illumina MiSeq reads for all Saccharomyces species. All are circularly mapped molecules decreasing in size with phylogenetic distance from Saccharomyces cerevisiae but with similar gene content including regulatory and selfish elements like origins of replication, introns, free-standing open reading frames or GC clusters. Their most profound feature is species-specific alteration in gene order. The genetic code slightly differs from well-established yeast mitochondrial code as GUG is used rarely as the translation start and CGA and CGC code for arginine. The multilocus phylogeny, inferred from mtDNA, does not correlate with the trees derived from nuclear genes. mtDNA data demonstrate that Saccharomyces cariocanus should be assigned as a separate species and Saccharomyces bayanus CBS 380T should not be considered as a distinct species due to mtDNA nearly identical to Saccharomyces uvarum mtDNA. Apparently, comparison of mtDNAs should not be neglected in genomic studies as it is an important tool to understand the origin and evolutionary history of some yeast species.