title: New evidence from Sinapis alba L. for ancestral triplication in a crucifer genome.
abstract: We present clear evidence of ancestral genome triplication in Sinapis alba, a close relative of the cultivated Brassica species. Exceptionally high levels of heterozygosity in the parents of an F1 intercross permitted the mapping of an estimated 87% of all detected restriction fragment length polymorphism (RFLP) loci, with each RFLP probe typically detecting 2 or 3 loci. These duplicated loci were arranged in 8 triplicated homologous linkage blocks and 2 small, duplicated, homologous linkage blocks covering the majority of the S. alba genome. Several large-scale inversions and translocations appear to have rearranged the order of loci within homologous blocks. The role of successive polyploidization events on the evolution of crucifer species is discussed.
authors.affiliation: School of Plant Biology, Faculty of Natural and Agricultural Sciences, University of Western Australia, 35 Stirling Highway, Crawley, 6009 WA, Australia. mnelson@plants.uwa.edu.au
authors.forename: Matthew N
authors.initials: MN
authors.lastname: Nelson
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Lydiate
mesh_terms: D019607:Brassicaceae / Q000235:genetics*; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D003433:Crosses, Genetic; D019143:Evolution, Molecular; D020440:Gene Duplication; D008040:Genetic Linkage; D005819:Genetic Markers; D018745:Genome, Plant; D006579:Heterozygote; D011110:Polymorphism, Genetic; D011123:Polyploidy; D031226:Sinapis / Q000235:genetics*
chemical_list: D005819:Genetic Markers