title: An integrated molecular cytogenetic map of Cucumis sativus L. chromosome 2.
abstract: BACKGROUND
  Integration of molecular, genetic and cytological maps is still a challenge for most plant species. Recent progress in molecular and cytogenetic studies created a basis for developing integrated maps in cucumber (Cucumis sativus L.).
  
  
  RESULTS
  In this study, eleven fosmid clones and three plasmids containing 45S rDNA, the centromeric satellite repeat Type III and the pericentriomeric repeat CsRP1 sequences respectively were hybridized to cucumber metaphase chromosomes to assign their cytological location on chromosome 2. Moreover, an integrated molecular cytogenetic map of cucumber chromosomes 2 was constructed by fluorescence in situ hybridization (FISH) mapping of 11 fosmid clones together with the cucumber centromere-specific Type III sequence on meiotic pachytene chromosomes. The cytogenetic map was fully integrated with genetic linkage map since each fosmid clone was anchored by a genetically mapped simple sequence repeat marker (SSR). The relationship between the genetic and physical distances along chromosome was analyzed.
  
  
  CONCLUSIONS
  Recombination was not evenly distributed along the physical length of chromosome 2. Suppression of recombination was found in centromeric and pericentromeric regions. Our results also indicated that the molecular markers composing the linkage map for chromosome 2 provided excellent coverage of the chromosome.
authors.affiliation: National Maize Improvement Center of China, Key Laboratory of Crop Genetic Improvement and Genome of Ministry of Agriculture, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing 100094, PR China. yhhan@genetics.ac.cn
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Han
authors.forename: Zhonghua
authors.initials: Z
authors.lastname: Zhang
authors.forename: Sanwen
authors.initials: S
authors.lastname: Huang
authors.forename: Weiwei
authors.initials: W
authors.lastname: Jin
mesh_terms: D002503:Centromere; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D018553:Cucumis sativus / Q000235:genetics*; D017404:In Situ Hybridization, Fluorescence