title: Microstructure of a Brassica rapa genome segment homoeologous to the resistance gene cluster on Arabidopsis chromosome 4.
abstract: Genome evolution is a continuous process and genomic rearrangement occurs both within and between species. With the sequencing of the Arabidopsis thaliana genome, comparative genetics and genomics offer new insights into plant biology. The genus Brassica offers excellent opportunities with which to compare genomic synteny so as to reveal genome evolution. During a previous genetic analysis of clubroot resistance in Brassica rapa, we identified a genetic region that is highly collinear with Arabidopsis chromosome 4. This region corresponds to a disease resistance gene cluster in the A. thaliana genome. Relying on synteny with Arabidopsis, we fine-mapped the region and found that the location and order of the markers showed good correspondence with those in Arabidopsis. Microsynteny on a physical map indicated an almost parallel correspondence, with a few rearrangements such as inversions and insertions. The results show that this genomic region of Brassica is conserved extensively with that of Arabidopsis and has potential as a disease resistance gene cluster, although the genera diverged 20 million years ago.
authors.affiliation: Graduate School of Bioresources, Mie University , 1577 Kurima-machiya, Tsu, Mie 514-8507, Japan ; NARO Institute of Vegetable and Tea Science , 360 Kusawa, Ano, Tsu, Mie 514-2392, Japan.
authors.forename: Keita
authors.initials: K
authors.lastname: Suwabe
authors.forename: Go
authors.initials: G
authors.lastname: Suzuki
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Nunome
authors.forename: Katsunori
authors.initials: K
authors.lastname: Hatakeyama
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Mukai
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Fukuoka
authors.forename: Satoru
authors.initials: S
authors.lastname: Matsumoto
keywords: BAC library; genome evolution; genome organization; genomic collinearity; microsynteny