| Budget Amount *help |
¥20,500,000 (Direct Cost: ¥20,500,000)
Fiscal Year 1986: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1985: ¥7,000,000 (Direct Cost: ¥7,000,000)
Fiscal Year 1984: ¥12,000,000 (Direct Cost: ¥12,000,000)
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| Research Abstract |
1.Since 1984, we have been studying the phylogenic relationship among a wide spectrum of extant living organisms using 5S RNA sequences. By comparing more than 350 5S RNA sequences from widely separated organisms, we have constructed a phylogenetic tree to obtain information on the representative groups of organisms, such as eubacteria, plants, multicellular animals, etc.
2. We proposed a hypothesis for evolution of the genetic code, using conclusions based on experimental observations. We emphasize wobble rules, evolution of anticodons and of transfer RNA, especially through gene duplication, AT/GC pressure in DNA (mutation pressure), observed differences from the universal code in mitochondria, Mycoplasma (UGA : tryptophan codon), and ciliated protozoa, and phylogenetic separation of kingdoms of organisms deduced from the 5S RNA sequences.
Consideration of these and other observations including codon usages in ribosomal proteins in Micrococcus and Mycoplasma done in our laboratory enables a coherent scheme for evolution of the code, following the first establishment of a code for 20 amino acids, to be formulated.
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