title: Development and evaluation of single-nucleotide polymorphism  markers in allotetraploid rapeseed (Brassica napus L.).
abstract: Single-nucleotide polymorphisms (SNPs) and insertion-deletions (INDELs) are currently the important classes of genetic markers for major crop species. In this study, methods for developing SNP markers in rapeseed (Brassica napus L.) and their in silico mapping and use for genotyping are demonstrated. For the development of SNP and INDEL markers, 181 fragments from 121 different gene sequences spanning 86 kb were examined. A combination of different selection methods (genome-specific amplification, hetero-duplex analysis and sequence analysis) allowed the detection of 18 singular fragments that showed a total of 87 SNPs and 6 INDELs between 6 different rapeseed varieties. The average frequency of sequence polymorphism was estimated to be one SNP every 247 bp and one INDEL every 3,583 bp. Most SNPs and INDELs were found in non-coding regions. Polymorphism information content values for SNP markers ranged between 0.02 and 0.50 in a set of 86 varieties. Using comparative genetics data for B. napus and Arabidopsis thaliana, an allocation of SNP markers to linkage groups in rapeseed was achieved: a unique location was determined for seven gene sequences; two and three possible locations were found for six and four sequences, respectively. The results demonstrate the usefulness of existing genomic resources for SNP discovery in rapeseed.
authors.affiliation: Plant Breeding, Department of Plant Sciences, Center of Life and Food Sciences Weihenstephan, Technische Universität München, Am Hochanger 4, 85350 Freising, Germany. peter.westermeier@wzw.tum.de
authors.forename: Peter
authors.initials: P
authors.lastname: Westermeier
authors.forename: Gerhard
authors.initials: G
authors.lastname: Wenzel
authors.forename: Volker
authors.initials: V
authors.lastname: Mohler
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000235:genetics; D029688:Brassica napus / Q000235:genetics*; D029741:Brassica rapa / Q000235:genetics*; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D017931:DNA Primers; D018744:DNA, Plant / Q000235:genetics; D005787:Gene Frequency; D005819:Genetic Markers; D014644:Genetic Variation; D018745:Genome, Plant; D005838:Genotype; D054643:INDEL Mutation; D017354:Point Mutation; D020641:Polymorphism, Single Nucleotide; D011123:Polyploidy
chemical_list: D017931:DNA Primers; D018744:DNA, Plant; D005819:Genetic Markers