title: Experimental evidence supports a sex-specific selective sieve in mitochondrial genome evolution.
abstract: Mitochondria are maternally transmitted; hence, their genome can only make a direct and adaptive response to selection through females, whereas males represent an evolutionary dead end. In theory, this creates a sex-specific selective sieve, enabling deleterious mutations to accumulate in mitochondrial genomes if they exert male-specific effects. We tested this hypothesis, expressing five mitochondrial variants alongside a standard nuclear genome in Drosophila melanogaster, and found striking sexual asymmetry in patterns of nuclear gene expression. Mitochondrial polymorphism had few effects on nuclear gene expression in females but major effects in males, modifying nearly 10% of transcripts. These were mostly male-biased in expression, with enrichment hotspots in the testes and accessory glands. Our results suggest an evolutionary mechanism that results in mitochondrial genomes harboring male-specific mutation loads.
authors.affiliation: Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18-D, 75236 Uppsala, Sweden.
authors.forename: Paolo
authors.initials: P
authors.lastname: Innocenti
authors.forename: Edward H
authors.initials: EH
authors.lastname: Morrow
authors.forename: Damian K
authors.initials: DK
authors.lastname: Dowling
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D004331:Drosophila melanogaster / Q000235:genetics* / Q000502:physiology; D019143:Evolution, Molecular; D005260:Female; D005298:Fertility; D015870:Gene Expression; D020869:Gene Expression Profiling; D017344:Genes, Insect; D056084:Genetic Fitness; D049750:Genome, Insect; D054629:Genome, Mitochondrial; D008297:Male; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D011110:Polymorphism, Genetic; D012641:Selection, Genetic; D012727:Sex Characteristics; D014158:Transcription, Genetic
chemical_list: D004272:DNA, Mitochondrial