Selfish gene leaves bacteria behind

A. York,  Nature Reviews Microbiology,  2021.

Mitochondrial genome evolution is characterized by functional streamlining and gene loss, and gain-of-function gene transfers into the mitochondrial genome are considered rare events. Milner, et al. identified a functional restriction modification (R-M) system in the mitochondrial genome of a marine protist that originated in bacteria. The type II R-M system was found in the mitochondrial genome of a marine heterotrophic katablepharid protist, and phylogenetic analyses suggest that the selfish genetic element consisting of an HpaII-like endonuclease and a cognate cytosine methyltransferase originated in bacteria within or related to Flavobacteriaceae. The authors showed that the R-M system is functional in both bacteria and yeast, and that a toxin–antitoxin relationship exists between the two proteins. The authors posit that the toxin–antitoxin function of the R-M system may have been co-opted to control biased or uniparental inheritance of mitochondria.

More related to this:

A functional bacteria-derived restriction modification system in the mitochondrion of a heterotrophic protist

Introduction of a male-harming mitochondrial haplotype via ‘Trojan Females’ achieves population suppression in fruit flies

The association between mitochondrial genetic variation and reduced colony fitness in an invasive wasp

The Trojan Female Technique for pest control: a candidate mitochondrial mutation confers low male fertility across diverse nuclear backgrounds in Drosophila melanogaster