title: [Physical localization of ribosomal genes and chromosome DAPI banding by in situ hybridization in Medicago sativa L].
abstract: Physical localization of ribosomal genes in diploid and tetraploid alfalfa (Medicago. sativa) was studied using fluorescent in situ hybridization (FISH). It was revealed that 45s gene was only located at nucleolus organizer region (NOR) with a single locus in both diploid and tetraploid alfalfa, while 5s gene had 2-3 loci on chromosomes. Using the genomic DNA from M. coerulea and M. falcata as probe to hybridize with tetraploid species in alfalfa, both diploid species were successfully hybridized with tetraploid chromosomes, only showing the difference in hybridization signals in different numbers of chromosomes. Chromosomes of alfalfa exhibited DAPI banding by FISH analysis. In general, the patterns of distribution of DAPI banding were consistent with C-banding for M. coerulea. The possible origination of tetraploid alfalfa was discussed based on DAPI banding patterns and FISH analysis for ribosomal genes .
authors.affiliation: College of Agriculture, Nanjing Agricultural University, Nanjing 210095, China. jmchen@yzu.edu.cn
authors.forename: Jian-Min
authors.initials: JM
authors.lastname: Chen
authors.forename: Yi-Huan
authors.initials: YH
authors.lastname: Hong
authors.forename: You-Ping
authors.initials: YP
authors.lastname: Wang
authors.forename: Steve
authors.initials: S
authors.lastname: Bowley
authors.forename: Jian-Min
authors.initials: JM
authors.lastname: Wan
mesh_terms: D002871:Chromosome Banding / Q000379:methods*; D032461:Chromosomes, Plant / Q000235:genetics*; D004275:DNA, Ribosomal / Q000235:genetics*; D017404:In Situ Hybridization, Fluorescence; D000455:Medicago sativa / Q000235:genetics*
chemical_list: D004275:DNA, Ribosomal