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Science Frontiers ONLINE No. 11: Summer 1980 |
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Hierarchies Of Evolution
All organisms from man to mouse to amoeba are merely DNA's way of manufacturing still more DNA -- so goes the modern ramification of molecular biology and the Genetic Code. In other words, DNA and genes are selfish, and ultimate parasites, directing the evolution of life only to maximize the production of DNA.
This theme is not the subject of this paper by Doolittle and Sapienza. Rather, they wonder about those nonsense DNA sequences that do not code for protein. The presence of these "useless" bits of genetic material is often explained in terms of gene "expression." Emphasis is always on maximizing the "fitness" of the organism (phenotype). Perhaps this seemingly excess genetic material actually maximizes the fitness (survivability) of the DNA itself. Evolution thus occurs at DNA and gene (genome) levels, despite what transpires at the organism (phenotype) level.
(Doolittle, W. Ford, and Sapienza, Carmen; "Selfish Genes, the Phenotype Paradigm and Genome Evolution," Nature, 284:601, 1980.)
Comment. We know that mitochondria and chloroplasts have their own genetic material; evolution may be occurring at this level, too, independent of pressures for change on the organisms. Waxing speculative, may there not be other hierarchies where systems are trying to maximize their own survivability, even at molecular, atomic, and subatomic levels? Don't laugh! Is not all life implicitly encoded in the properties of the most fundamental particles? If not, reductionism is a lie.