Plant Genome IV Conference

S18
Comparative Analysis of Plant Genome Structure

In the reference genome, sugar beet (Beta vulgaris), we have identified most of the major repetitive DNA motifs. More than seven high copy repeat element classes, the majority of high copy microsatellites and two different retrotransposon classes have been isolated and characterized by their sequences, genomic organization determined by Southern hybridization, and the physical distribution shown by in situ hybridization to metaphase chromosomes and interphase nuclei. A structural model of the genome, incorporating gene-rich regions, has been developed. We can demonstrate how repetitive DNA contributes to the structure of plant chromosomes and defines some of the differences between closely related plant genomes. In species varying from Arabidopsis thaliana to pine with genome sizes ranging from little more than 100 Mbp to nearly 25000 Mbp, we show by comparative in situ hybridization that the organization of repeats is similar but some repeat classes show also contrasting distribution patterns in some species.
T.S. acknowledges financial support by EU fellowship ERB4001GT931647.