Most analyses of how the genome affects a plant’s or animal’s characteristics are confined to the nuclear genome, but researchers recently found that more than 80% of the metabolites in a plant model organism, Arabidopsis, are directly affected by variations in organellar genes, which are found in mitochondria and other organelles outside the nucleus (Joseph B et al. Elife. 2013;2:e00776). Also, organellar genes regulated the activity of nuclear genes that in turn affected metabolism.
Hampton T. Genes Outside the Nucleus Have Large Effects on Cell Metabolism. JAMA. 2013;310(22):2389. doi:10.1001/jama.2013.283995