Mobile DNA II

This book documents the remarkable mobility of DNAs in procaryotic and eucaryotic genomes: the ability of various DNA segments to move to new sites, to invert, and to undergo deletion or amplification, generally without the extensive DNA sequence homology needed for classical recombination.Its chapters describe the variety of mechanisms by which these rearrangements occur, how they are regulated, their biological consequences, and ways in which transposable elements can be exploited as potent research tools.The many examples of mobile DNAs now known provide important exceptions to the general principle that gene and DNA sequence arrangements are stable and transmitted with great fidelity from parents to progeny.Some rearrangements, such as the movement of bacterial antibiotic resistance transposons, variation in surface antigen genes in certain pathogens, and gene amplification in mammalian cells, are typically quite rare, but are brought into prominence by selective pressure in large populations. At the other extreme, antibody gene rearrangements, DNA elimination and amplification in ciliated protozoans, integration of phage, and transposition of phage Mu can all be very frequent, but are regulated developmentally or restricted to specific cell types or nuclei.