GENOMIC ORGANIZATION AND SEQUENCE ANALYSIS OF REPLICATED LOCI IN B. oleracea

Horticulture Research International, Wellesbourne, Warwick, CV35 9EF, UK

Brassica genomes possess a more complex organisation than that of the related crucifer Arabidopsis. As such they are ideal for studying the properties and behavior of crop genomes. Our group is carrying out systematic and detailed analysis of developmental gene families in Brassica oleracea, including MADS-box, AUX-1 and small heat shock protein. We are comparing locus and species variation in coding and non-coding sequences. Contrasting patterns of sequence variation have been observed in 5' regulatory regions of MADS-box and HSP-17 loci. The ramifications of locus replication in crop brassicas will be discussed in the context of developmental and environmental adaptations of regulatory genes. The higher order interactions which are possible may be studied through networks of genes which interact through their direct transcriptionally activation. There is a need for development of appropriate methods, in the context of increased genome complexity, for analysis and hypothesis testing when assigning gene function. In particular, with the availability of functional genomics tools such as DNA chips, there is an urgent requirement for development of methods which distinguish accurately between transcripts arising from replicated loci.