429 13.2 Transposable elements in prokaryotes Transposable elements: only in maize? Although geneticists readily accepted McClintock’s dis-covery of transposable elements in maize, many were re-luctant to consider the possibility that similar elements resided in the genomes of other organisms. Their existence in all organisms would imply that genomes are inherently unstable and dynamic. This view was inconsistent with the fact that the genetic maps of members of the same species were the same. After all, if genes can be genetically mapped to a precise chromosomal location, doesn’t this mapping indicate that they are not moving around? Because McClintock was a highly respected geneti-cist, her results were explained by saying that maize is not a natural organism; it is a crop plant that is the prod-uct of human selection and domestication. This view was held by some until the 1960s when the Frst trans-posable elements were isolated from the E. coli genome and studied at the DNA sequence level. Transposable el-ements were subsequently isolated from the genomes of
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This note was uploaded on 01/10/2011 for the course BIOL BIOL taught by Professor Johnson during the Spring '08 term at Aberystwyth University.