YBR163W EXO5 SGDID:S000000367, Chr II from 565723-567480, Genome Release 64-1-1, Verified ORF, "Mitochondrial 5'-3' exonuclease and sliding exonuclease, required for mitochondrial genome maintenance; distantly related to the RecB nuclease domain of bacterial RecBCD recombinases; may be regulated by the transcription factor Ace2"