摘要：

This chapter describes animal mitochondrial DNA. It focuses on the aspects of the structure, function, and evolution of animal mitochondrial DNA (mtDNA). It also explores the questions raised by the recent unravelling of the mitochondrial genetic code and of the primary structure and gene organization of animal mtDNA. The most conspicuous among the features of animal mtDNA from animal cells, yeast, and filamentous fungi, is the use of UGA as a tryptophan codon rather than as a stop codon. There are genetic code differences between the individual mitochondrial genetic systems, even within the same philogenetic group. In mammalian, but not in fungal mitochondria, besides AUG, also AUA, AUU, and AUC can function as initiator codons; in this role, AUU and AUC may indeed be read by N -formyl-methionyl-tRNA and thus code for N -formyl-methionine, like AUG and AUA. There is a case among mammalian mitochondrial tRNAs where a C in the first position of the anticodon, rather than a U, enables it to pair with A and G in third codon position. The mtDNA of all animal cells so far analyzed is in the form of circular molecules of relatively uniform length, with their sizes ranging between 15.7 and 19.5 kb.

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