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Recent genome sequencing papers have given genome sizes of 180 Mb for Drosophila melanogaster Iso-1 and 125 Mb for Arabidopsis thaliana Columbia. The former agrees with early cytochemical estimates, but numerous cytometric estimates of around 170 Mb imply that a genome size of 125 Mb for arabidopsis is an underestimate. In this study, nuclei of species(More)
BACKGROUND AND AIMS Brassicaceae, with nearly 340 genera and more than 3350 species, anchors the low range of angiosperm genome sizes. The relatively narrow range of DNA content (0.16 pg < 1C < 1.95 pg) was maintained in spite of extensive chromosomal change. The aim of this study was to erect a cytological and molecular phylogenetic framework for a(More)
Flow cytometry was used to compare 14 potential reference standards for plant DNA content determination. Both chicken and plant internal standards were used, as were propidium iodide (PI) and 4'-6-diamidino-2-phenylindole (DAPI) as fluorochromes. Means and standard errors of the means are presented for the 14 potential reference standards, and the means are(More)
Polyploid formation has played a major role in the evolution of many plant and animal genomes; however, surprisingly little is known regarding the subsequent evolution of DNA sequences that become newly united in a common nucleus. Of particular interest is the repetitive DNA fraction, which accounts for most nuclear DNA in higher plants and animals and(More)
Plant genomes vary over several orders of magnitude in size, even among closely related species, yet the origin, genesis and significance of this variation are not clear. Because DNA content varies over a sevenfold range among diploid species in the cotton genus (Gossypium) and its allies, this group offers opportunities for exploring patterns and(More)
In situ DNA hybridization with 18S-28S and 5S ribosomal DNA probes was used to map 18S-28S nucleolar organizers and tandem 5S repeats to meiotic chromosomes of cotton (Gossypium hirsutum L.). Mapping was performed by correlating hybridization sites to particular positions in translocation quadrivalents. Arm assignment required translocation quadrivalents(More)
Lycopersicon esculentum (tomato) has a small genome (2C = 1.90 pg of DNA) packaged in 2n = 2x = 24 small acrocentric to metacentric chromosomes. Like the chromosomes of other members of the family Solanaceae, tomato chromosomes have pericentromeric heterochromatin. To determine the fraction of the tomato genome found in euchromatin versus heterochromatin,(More)
The most widely cultivated species of cotton, Gossypium hirsutum, is a disomic tetraploid (2n=4x=52). It has been proposed previously that extant A- and D-genome species are most closely related to the diploid progenitors of the tetraploid. We used fluorescent in situ hybridization (FISH) to determine the distribution of 5S and 18S-28S rDNA loci in the(More)
BACKGROUND AND AIMS The roles of variation in DNA content in plant evolution and adaptation remain a major biological enigma. Chromosome number and 2C DNA content were determined for 21 of the 25 species of the genus Sorghum and analysed from a phylogenetic perspective. METHODS DNA content was determined by flow cytometry. A Sorghum phylogeny was(More)
Linkage group identities and homologies were determined for metaphase chromosomes of Sorghum bicolor (2n = 20) by FISH of landed BACs. Relative lengths of chromosomes in FISH-karyotyped metaphase spreads of the elite inbred BTx623 were used to estimate the molecular size of each chromosome and to establish a size-based nomenclature for sorghum chromosomes(More)