Is the Mitochondrial Genome Still Functional?
Mitochondrial genomes are very small
and show a great deal of variation as a result of divergent evolution.
Mitochondrial genes that have been conserved across evolution include rRNA genes
, tRNA genes, and a small number of genes that encode proteins involved in electron transport and ATP synthesis. The mitochondrial genome retains similarity to its prokaryotic ancestor, as does some of the machinery mitochondria use to synthesize proteins. In fact, mitochondrial rRNAs more closely resemble bacterial rRNAs than the eukaryotic rRNAs found in cell cytoplasm. In addition, some of the codons that mitochondria use to specify amino acids differ from the standard eukaryotic codons