title: Uniqueness of the Gossypium mustelinum genome revealed by GISH and 45S rDNA FISH.
abstract: Gossypium mustelinum ((AD)4 ) is one of five disomic species in Gossypium. Three 45S ribosomal DNA (rDNA) loci were detected in (AD)4 with 45S rDNA as probe, and three pairs of brighter signals were detected with genomic DNA (gDNA) of Gossypium D genome species as probes. The size and the location of these brighter signals were the same as those detected with 45S rDNA as probe, and were named GISH-NOR. One of them was super-major, which accounted for the fact that about one-half of its chromosome at metaphase was located at chromosome 3, and other two were minor and located at chromosomes 5 and 9, respectively. All GISH-NORs were located in A sub-genome chromosomes, separate from the other four allopolyploid cotton species. GISH-NOR were detected with D genome species as probe, but not A. The greatly abnormal sizes and sites of (AD)4 NORs or GISH-NORs indicate a possible mechanism for 45S rDNA diversification following (AD)4 speciation. Comparisons of GISH intensities and GISH-NOR production with gDNA probes between A and D genomes show that the better relationship of (AD)4 is with A genome. The shortest two chromosomes of A sub-genome of G. mustelinum were shorter than the longest chromosome of D sub-genome chromosomes. Therefore, the longest 13 chromosomes of tetraploid cotton being classified as A sub-genome, while the shorter 13 chromosomes being classified as D sub-genome in traditional cytogenetic and karyotype analyses may not be entirely correct.
authors.affiliation: Cotton Research Institute, the Chinese Academy of Agricultural Sciences/National Key Laboratory of Cotton Biology, Anyang 455000, China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Wu
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.forename: Shaohui
authors.initials: S
authors.lastname: Li
authors.forename: Guoli
authors.initials: G
authors.lastname: Song
authors.forename: Chunying
authors.initials: C
authors.lastname: Wang
authors.forename: Xiangdi
authors.initials: X
authors.lastname: Zhang
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Wang
authors.forename: David
authors.initials: D
authors.lastname: Stelly
authors.forename: Kunbo
authors.initials: K
authors.lastname: Wang
mesh_terms: D032461:Chromosomes, Plant / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics*; D004171:Diploidy; D018745:Genome, Plant / Q000235:genetics*; D003368:Gossypium / Q000235:genetics*; D006824:Hybridization, Genetic; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008677:Metaphase / Q000235:genetics; D009697:Nucleolus Organizer Region / Q000235:genetics; D011058:Pollen / Q000166:cytology
chemical_list: D018744:DNA, Plant; D004275:DNA, Ribosomal
keywords: Chromosomes; Gossypium mustelinum; cotton; genome; in situ hybridization; nucleolar organizer region