The Plant Mitochondrial Transfer RNAs Have Three Different Genetic Origins

In mammals and fungi, the mitochondrial (mt) genome contains 22-24 transfer RNA (tRNA) genes and the corresponding tRNA population is sufficient to allow the incorporation of all 20 amino acids into proteins, thanks to a number of unusual codon-anticodon interactions which enable this apparently incomplete tRNA set to read all 61 sense codons (Marechal-Drouard et al 1992).