Comparing Arabidopsis to other flowering plants.

Comparisons of the Arabidopsis genomic sequence with sequences from other flowering plants have revealed that substantial colinearity exists between species in the arrangement of genes within chromosomal blocks. Although seen most clearly in short sequences (at the Megabase scale), this colinearity can also be found using dense genetic maps that are based on expressed sequence tags. The genomes of most diploid Angiosperms show evidence of polyploid ancestry, and the resulting duplicated blocks, which have been subject to deletion and rearrangements during evolution, form complex networks of homology both within and between species. These homologies should prove to be of value in exploiting the Arabidopsis sequence to identify candidate genes in defined chromosomal regions within genomes that are less well characterised.