Extensive duplication and reshuffling in the arabidopsis genome

Systematic analysis of the Arabidopsis genome provides a basis for detailed studies of genome structure and evolution. Members of multigene families w ere mapped, and random sequence alignment was used to identify regions of e xtended similarity in the Arabidopsis genome. Detailed analysis showed that the number, order, and orientation of genes were conserved over large regi ons of the genome, revealing extensive duplication covering the majority of the known genomic sequence. Fine mapping analysis showed much rearrangemen t, resulting in a patchwork of duplicated regions that indicated deletion, insertion, tandem duplication, inversion, and reciprocal translocation. The implications of these observations for evolution of the Arabidopsis genome as well as their usefulness for analysis and annotation of the genomic seq uence and in comparative genomics are discussed.