MITOCHONDRIAL GENETIC CODE
The genetic code of the mitochondrial DNA differs from the universal genetic code. Every species has its own features in mitochondrial genetic code, and also there are general dissimilitudes between the universal code and the mitochondrial one. As a rule, the mitochondrial genetic code is more simple than the universal one. It allows to reduce the number of tRNA, which are necessary for protein translation. It is connected, primarily, with the fact, that for providing intramitochondrial synthesis of a small amount of proteins, under the conditions of stable intracellular environment for the mitochondria themselves, during the evolution a possibility for unusual ways of organization and expression of genetic information appeared. For the code, which is used in mitochondria, complete degeneracy of the third base is characteristic (in the universal code this degeneracy is partial). The fact of existence of an especial mitochondrial genetic code allows biologists to discuss items of evolution of the genetic code.
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Supplementary information
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