Comparison of the Human and Bovine Mitochondrial Genomes

Abstract

The complete DNA sequences of both the human and the bovine mitochondrial genomes have been determined recently (Anderson et al. 1981; S. Anderson et al., in prep.). Because these two genomes exhibit a high degree of homology and virtually identical organization, they can be interpreted as a unit, allowing a more comprehensive understanding of mammalian mitochondrial gene expression and gene-product structure.

The sequences of the human and bovine mtDNAs can serve to link up several important bodies of evidence. For example, the precise mapping of human mitochondrial transcripts (Ojala et al. 1980), combined with the amino acid sequences of bovine proteins such as cytochrome oxidase subunit II (COII) (Steffens and Buse 1979), enables one to predict confidently that the large open reading frames conserved in both the human and the bovine mitochondrial genomes (Anderson et al. 1981) (Fig. 1) are functional protein-coding genes. Similarly, the mapping and charging data for human mitochondrial tRNAs (Angerer et al. 1976; Lynch and Attardi 1976) and the sequence data for bovine mitochondrial tRNAs (Roe et al., this volume; B. A. Roe et al., in prep.) enable one to locate precisely the positions of the tRNA genes in the two genomes. Finally, with two complete mammalian mitochondrial genome sequences it is possible to examine the pattern of mtDNA sequence conservation during mammalian evolution. Such a comparative study can yield information about the relative importance of various structural features found in macromolecules coded in the mitochondrial genome.

The human mitochondrial genetic system has been found to...