Mitochondrial fission proteins Fis1 and Mdv1, but not Dnm1, play a role in maintenance of heteroplasmy in budding yeast

► The absence of Fis1 or Mdv1, but not Dnm1, increases initial homoplasmy levels. ► The null mutations Δfis1 or Δmdv1, but not Δdnm1, accelerate mtDNA allele-segregation. ► MtDNA copy number alone did not account for the increased homoplasmy levels. ► Certain fission proteins maintain heteroplasmy.