Kurland C G
Department of Molecular Biology, Biomedical Center, Uppsala, Sweden.
Bioessays. 1992 Oct;14(10):709-14. doi: 10.1002/bies.950141013.
Mitochondrial genomes are clearly marked by a strong tendency towards reductive evolution. This tendency has been facilitated by the transfer of most of the essential genes for mitochondrial propogation and function to the nuclear genome. The most extreme examples of genomic simplification are seen in animal mitochondria, where there also are the greatest tendencies to codon reassignment. The reassignment of codons to amino acids different from those designated in the so called universal code is seen in part as an expression of the reduction of the number of genes used by these genomes to code for tRNA species. The driving force for the reductive evolution of mitochondrial genomes is identified with two population genetic effects which may also be operating on populations of parasites.
线粒体基因组明显呈现出强烈的简化进化趋势。这种趋势因线粒体繁殖和功能所需的大多数关键基因转移到核基因组而得到促进。基因组简化的最极端例子见于动物线粒体，其中密码子重新分配的趋势也最为明显。密码子被重新分配用于编码与所谓通用密码中指定氨基酸不同的氨基酸，部分原因被视为这些基因组用于编码tRNA种类的基因数量减少的一种表现。线粒体基因组简化进化的驱动力被认为与两种群体遗传效应有关，这两种效应可能也作用于寄生虫群体。
