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The RNA world hypothesis places RNA at center-stage when life originated. The RNA world hypothesis is supported by the observations that ribosomes are ribozymes: [120] [121] the catalytic site is composed of RNA, and proteins hold no major structural role and are of peripheral functional importance. This was confirmed with the deciphering of ...
Kandler's pre-cell theory is supported by Wächtershäuser. [64] [65] In 1998, Carl Woese, based on the RNA world concept, proposed that no individual organism could be considered a LUCA, and that the genetic heritage of all modern organisms derived through horizontal gene transfer among an ancient community of organisms. [66]
In the eocyte hypothesis, the organism at the root of all eocytes may have been a ribocyte of the RNA-world. For cellular DNA and DNA handling, an "out of virus" scenario has been proposed: storing genetic information in DNA may have been an innovation performed by viruses and later handed over to ribocytes twice, once transforming them into bacteria and once transforming them into archaea.
This concept is known as the RNA world hypothesis. According to this hypothesis, the ancient RNA world transitioned into the modern cellular world via the evolution of protein synthesis, followed by replacement of many cellular ribozyme catalysts by protein-based enzymes.
RNA-based evolution is a theory that posits that RNA is not merely an intermediate between Watson and Crick model of the DNA molecule and proteins, but rather a far more dynamic and independent role-player in determining phenotype.
A simple genotype–phenotype map. In later years, a new paradigm emerged, that placed RNA as a precursor molecule to DNA. A primordial molecule principle was put forth as early as 1968 by Crick, [30] and lead to what is now known as The RNA World Hypothesis. [31]
Evolution is the change in the heritable characteristics of biological populations over successive generations. [1] [2] It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, resulting in certain characteristics becoming more or less common within a population over successive generations. [3]
Independent replicators (probably RNA) Chromosomes: RNA world hypothesis: RNA as both genes and enzymes: DNA as genes; proteins as enzymes Prokaryotes: Eukaryotes: Can observe [clarification needed] Asexual clones: Sexual populations: Evolution of sex: Protists: Multicellular organisms — animals, plants, fungi: Evolution of multicellularity ...