Chromosomal Rearrangements

Abstract

Repeated sequences provide the potential for altering and destabilizing the genome (reviewed by Petes and Hill, 1988). Multigene families, IS elements and shorter repeated sequences like REP (Higgins et al., 1982; Gibson et al., 1984; Stern et al., 1984; Dimri et al., 1992) and ERIC (Sharpies and Lloyd, 1990; Hulton et al., 1991) are dispersed throughout bacterial genomes (reviewed by Riley and Krawiec, 1987; Lupski and Weinstock, 1992; see also Chapters 4 and 5). These sequences provide regions of homology for unequal crossing-over events. Such ectopic recombination events can lead to inversions, deletions, or duplications of regions of the chromosome. An inversion results when the repeated sequences involved in the recombination event are in inverse orientation to one another on the chromosome. Deletions and tandem duplications result from ectopic recombination between repeated sequences in the same or tandem orientation (Figure 11-1).