title: An EST-SSR linkage map of Raphanus sativus and comparative genomics of the Brassicaceae.
abstract: Raphanus sativus (2n = 2x = 18) is a widely cultivated member of the family Brassicaceae, for which genomic resources are available only to a limited extent in comparison to many other members of the family. To promote more genetic and genomic studies and to enhance breeding programmes of R. sativus, we have prepared genetic resources such as complementary DNA libraries, expressed sequences tags (ESTs), simple sequence repeat (SSR) markers and a genetic linkage map. A total of 26 606 ESTs have been collected from seedlings, roots, leaves, and flowers, and clustered into 10 381 unigenes. Similarities were observed between the expression patterns of transcripts from R. sativus and those from representative members of the genera Arabidopsis and Brassica, indicating their functional relatedness. The EST sequence data were used to design 3800 SSR markers and consequently 630 polymorphic SSR loci and 213 reported marker loci have been mapped onto nine linkage groups, covering 1129.2 cM with an average distance of 1.3 cM between loci. Comparison of the mapped EST-SSR marker positions in R. sativus with the genome sequence of A. thaliana indicated that the Brassicaceae members have evolved from a common ancestor. It appears that genomic fragments corresponding to those of A. thaliana have been doubled and tripled in R. sativus. The genetic map developed here is expected to provide a standard map for the genetics, genomics, and molecular breeding of R. sativus as well as of related species. The resources are available at http://marker.kazusa.or.jp/Daikon.
authors.affiliation: Kazusa DNA Research Institute, Chiba, Japan. shirasaw@kazusa.or.jp
authors.forename: Kenta
authors.initials: K
authors.lastname: Shirasawa
authors.forename: Maki
authors.initials: M
authors.lastname: Oyama
authors.forename: Hideki
authors.initials: H
authors.lastname: Hirakawa
authors.forename: Shusei
authors.initials: S
authors.lastname: Sato
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tabata
authors.forename: Takashi
authors.initials: T
authors.lastname: Fujioka
authors.forename: Chiaki
authors.initials: C
authors.lastname: Kimizuka-Takagi
authors.forename: Shigemi
authors.initials: S
authors.lastname: Sasamoto
authors.forename: Akiko
authors.initials: A
authors.lastname: Watanabe
authors.forename: Midori
authors.initials: M
authors.lastname: Kato
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Kishida
authors.forename: Mitsuyo
authors.initials: M
authors.lastname: Kohara
authors.forename: Chika
authors.initials: C
authors.lastname: Takahashi
authors.forename: Hisano
authors.initials: H
authors.lastname: Tsuruoka
authors.forename: Tsuyuko
authors.initials: T
authors.lastname: Wada
authors.forename: Takako
authors.initials: T
authors.lastname: Sakai
authors.forename: Sachiko
authors.initials: S
authors.lastname: Isobe
mesh_terms: D002874:Chromosome Mapping; D020224:Expressed Sequence Tags; D008040:Genetic Linkage; D018745:Genome, Plant; D023281:Genomics; D018895:Microsatellite Repeats / Q000235:genetics*; D059372:Nucleotide Motifs; D031224:Raphanus / Q000235:genetics*