title: Comparison of wheat physical maps with barley linkage maps for group 7 chromosomes.
abstract: Comparative genetic maps among the Triticeae or Gramineae provide the possibility for combining the genetics, mapping information and molecular-marker resources between different species. Dense genetic linkage maps of wheat and barley, which have a common array of molecular markers, along with deletion-based chromosome maps of Triticum aestivum L. will facilitate the construction of an integrated molecular marker-based map for the Triticeae. A set of 21 cDNA and genomic DNA clones, which had previously been used to map barley chromosome 1 (7H), were used to physically map wheat chromosomes 7A, 7B and 7D. A comparative map was constructed to estimate the degree of linkage conservation and synteny of chromosome segments between the group 7 chromosomes of the two species. The results reveal extensive homoeologies between these chromosomes, and the first evidence for an interstitial inversion on the short arm of a barley chromosome compared to the wheat homoeologue has been obtained. In a cytogenetically-based physical map of group 7 chromosomes that contain restriction-fragment-length polymorphic DNA (RFLP) and random amplified polymorphic DNA (RAPD) markers, the marker density in the most distal third of the chromosome arms was two-times higher than in the proximal region. The recombination rate in the distal third of each arm appears to be 8-15 times greater than in the proximal third of each arm where recombination of wheat chromosomes is suppressed.
authors.affiliation: Botanisches Institut der Ludwig-Maximilians-Universität München, Menzinger Strasse 67, D-80638, München, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Hohmann
authors.forename: A
authors.initials: A
authors.lastname: Graner
authors.forename: T R
authors.initials: TR
authors.lastname: Endo
authors.forename: B S
authors.initials: BS
authors.lastname: Gill
authors.forename: R G
authors.initials: RG
authors.lastname: Herrmann