Mitochondrial Recombination Reveals Mito–Mito Epistasis in Yeast

Genetics: A Periodical Record of Investigations Bearing on Heredity and Variation

John F. Wolters^1¹  Christian R. Landry^3²  Alec Gaspary^1³  Guillaume Charron^2⁴ 

[1] Department of Biological Sciences, Binghamton University, New York 13902^1;Département de Biochimie, Microbiologie et Bio-informatique, Université Laval, Québec, Canada G1V 0A6^3;Département de Biologie, Institut de Biologie Intégrative et des Systèmes G1V 0A6;Département de Biologie, Institut de Biologie Intégrative et des Systèmes G1V 0A6^2

关键词: mtDNA;    mitochondrial recombination;    mito–mito epistasis;    genetic interactions;    Saccharomyces yeast;   

DOI  :  10.1534/genetics.117.300660

学科分类：医学（综合）

来源: Genetics Society of America

【 摘 要 】

Genetic variation in mitochondrial DNA (mtDNA) provides adaptive potential although the underlying genetic architecture of fitness components within mtDNAs is not known. To dissect functional variation within mtDNAs, we first identified naturally occurring mtDNAs that conferred high or low fitness in Saccharomyces cerevisiae by comparing growth in strains containing identical nuclear genotypes but different mtDNAs. During respiratory growth under temperature and oxidative stress conditions, mitotype effects were largely independent of nuclear genotypes even in the presence of mito–nuclear interactions. Recombinant mtDNAs were generated to determine fitness components within high- and low-fitness mtDNAs. Based on phenotypic distributions of isogenic strains containing recombinant mtDNAs, we found that multiple loci contributed to mitotype fitness differences. These mitochondrial loci interacted in epistatic, nonadditive ways in certain environmental conditions. Mito–mito epistasis ( i.e. , nonadditive interactions between mitochondrial loci) influenced fitness in progeny from four different crosses, suggesting that mito–mito epistasis is a widespread phenomenon in yeast and other systems with recombining mtDNAs. Furthermore, we found that interruption of coadapted mito–mito interactions produced recombinant mtDNAs with lower fitness. Our results demonstrate that mito–mito epistasis results in functional variation through mitochondrial recombination in fungi, providing modes for adaptive evolution and the generation of mito–mito incompatibilities.

【 授权许可】

CC BY