title: Sequence-level comparative analysis of the Brassica napus genome around two stearoyl-ACP desaturase loci.
abstract: We conducted a sequence-level comparative analyses, at the scale of complete bacterial artificial chromosome (BAC) clones, between the genome of the most economically important Brassica species, Brassica napus (oilseed rape), and those of Brassica rapa, the genome of which is currently being sequenced, and Arabidopsis thaliana. We constructed a new B. napus BAC library and identified and sequenced clones that contain homoeologous regions of the genome including stearoyl-ACP desaturase-encoding genes. We sequenced the orthologous region of the genome of B. rapa and conducted comparative analyses between the Brassica sequences and those of the orthologous region of the genome of A. thaliana. The proportion of genes conserved (approximately 56%) is lower than has been reported previously between A. thaliana and Brassica (approximately 66%). The gene models for sets of conserved genes were used to determine the extent of nucleotide conservation of coding regions. This was found to be 84.2 +/- 3.9% and 85.8 +/- 3.7% between the B. napus A and C genomes, respectively, and that of A. thaliana, which is consistent with previous results for other Brassica species, and 97.5 +/- 3.1% between the B. napus A genome and B. rapa, and 93.1 +/- 4.9% between the B. napus C genome and B. rapa. The divergence of the B. napus genes from the A genome and the B. rapa genes was greater than anticipated and indicates that the A genome ancestor of the B. napus cultivar studied was relatively distantly related to the cultivar of B. rapa selected for genome sequencing.
authors.affiliation: Department of Crop Genetics, John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, UK.
authors.forename: Kwangsoo
authors.initials: K
authors.lastname: Cho
authors.forename: Carmel M
authors.initials: CM
authors.lastname: O'Neill
authors.forename: Soo-Jin
authors.initials: SJ
authors.lastname: Kwon
authors.forename: Tae-Jin
authors.initials: TJ
authors.lastname: Yang
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Smooker
authors.forename: Fiona
authors.initials: F
authors.lastname: Fraser
authors.forename: Ian
authors.initials: I
authors.lastname: Bancroft
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics; D029688:Brassica napus / Q000201:enzymology / Q000235:genetics*; D029741:Brassica rapa / Q000201:enzymology / Q000235:genetics*; D002874:Chromosome Mapping; D022202:Chromosomes, Artificial, Bacterial; D055028:Comparative Genomic Hybridization; D018744:DNA, Plant / Q000235:genetics; D044943:Fatty Acid Desaturases / Q000235:genetics*; D015723:Gene Library; D017343:Genes, Plant; D018745:Genome, Plant; D008957:Models, Genetic; D010802:Phylogeny; D017422:Sequence Analysis, DNA
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; D044943:Fatty Acid Desaturases; C433487:stearoyl ACP desaturase, Arabidopsis