Why do we still have a maternally inherited mitochondrial DNA? Insights from evolutionary medicine.
The human cell is a symbiosis of two life forms, the nucleus-cytosol and the mitochondrion. The nucleus-cytosol emphasizes structure and its genes are Mendelian, whereas the mitochondrion specializes in energy and its mitochondrial DNA (mtDNA) genes are maternal. Mitochondria oxidize calories via oxidative phosphorylation (OXPHOS) to generate a mitochondrial inner membrane proton gradient (DeltaP). DeltaP then acts as a source of potential energy to produce ATP, generate heat, regulate reactive oxygen species (ROS), and control apoptosis, etc. Interspecific comparisons of mtDNAs have revealed that the mtDNA retains a core set of electron and proton carrier genes for the proton-translocating OXPHOS complexes I, III, IV, and V. Human mtDNA analysis has revealed these genes frequently contain region-specific adaptive polymorphisms. Therefore, the mtDNA with its energy controlling genes may have been retained to permit rapid adaptation to new environments.
Wallace
Douglas C
DC
Center for Molecular and Mitochondrial Medicine and Genetics, Department of Biological Chemistry, University of California, Irvine, California 92697-3940, USA. dwallace@uci.edu
D005075:Biological Evolution; D004272:DNA, Mitochondrial; D050259:Genes, Mitochondrial; D023281:Genomics; D006801:Humans; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D010085:Oxidative Phosphorylation; D010802:Phylogeny; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism
D004272:DNA, Mitochondrial; D024101:Mitochondrial Proteins; D021122:Protein Subunits