Mitochondrial transformation in yeast by bombardment with microprojectiles

The genetic transformation of mitochrondria and chloroplasts has been an intratable problem. The newly developed "biolistic" (biological ballistic) process was used deliver DNA into yeast cells to stably transform their mitchondria. A nonreverting strain, which is respiratory deficient because of a deletion in the mitochodrial axi3 gene, was bombarded with tungsten microprojectiles coated with DNA bring sequences that could correct the axi3 deletion. Respiratory-competent transformants were obtained in which the introduced axi3 DNA is intgrated at the homologous site in the mitochondrial genome. Organelle genomes can now be manipulated by molecular genetic tecniques in the same way as nuclear genomes.