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At least 109 records · Page 6Linked to original sources
PubMed2006

Anticancer cyclometalated [Au(III)m(C(wedge)N(wedge)C)mL]n+ compounds: Synthesis and cytotoxic properties.

A series of cyclometalated gold(III) compounds [Au(m)(C(wedge)N(wedge)C)mL]n+ (m = 1-3; n = 0-3; HC(wedge)N(wedge)CH = 2,6-diphenylpyridine) was prepared by ligand substitution reaction of L with N-donor or phosphine ligands. The [Au(m)(C(wedge)N(wedge)C)mL]n+ compounds are stable in solution in the presence of glutathione. Crystal structures of the gold(III) compounds containing bridging bi- and tridentate phosphino ligands reveal the presence of weak intramolecular pi pi stacking between the [Au(C(wedge)N(wedge)C)]+ units. Results of MTT assays demonstrated that the [Au(m)(C(wedge)N(wedge)C)mL]n+ compounds containing nontoxic N-donor auxiliary ligands (2) exert anticancer potency comparable to that of cisplatin, with IC50 values ranging from 1.5 to 84 microM. The use of [Au(C(wedge)N(wedge)C)(1-methylimidazole)]+ (2 a) as a model compound revealed that the gold(III)-induced cytotoxicity occurs through an apoptotic cell-death pathway. The cell-free interaction of 2 a with double-stranded DNA was also examined. Absorption titration showed that 2 a binds to calf-thymus DNA (ctDNA) with a binding constant of 4.5 x 10(5) dm3 mol(-1) at 298 K. Evidence from gel-mobility-shift assays and viscosity measurements supports an intercalating binding mode for the 2 a-DNA interaction. Cell-cycle analysis revealed that 2 a causes S-phase cell arrest after incubation for 24 and 48 hours. The cytotoxicity of 3 b-g toward cancer cells (IC50 = 0.04-4.3 microM) correlates to that of the metal-free phosphine ligands (IC50 = 0.1-38.0 microM), with [Au2(C(wedge)N(wedge)C)2(mu-dppp)]2+ (3 d) and dppp (dppp = 1,2-bis(diphenylphosphino)propane) being the most cytotoxic gold(III) and metal-free compounds, respectively. Compound 3 d shows a cytotoxicity at least ten-fold higher than the other gold(III) analogues; in vitro cellular-uptake experiments reveal similar absorptions for all the gold(III) compounds into nasopharyngeal carcinoma cells (SUNE1) (1.18-3.81 ng/cell; c.f., 3 d = 2.04 ng/cell), suggesting the presence of non-gold-mediated cytotoxicity. Unlike 2 a, both gold(III) compounds [Au(C(wedge)N(wedge)C)(PPh3)]+ (3 a) (PPh3 = triphenylphosphine) and [Au2(C(wedge)N(wedge)C)2(mu-dppp)]2+ (3 d) interact only weakly with ctDNA and do not arrest the cell cycle.

Antineoplastic Agents↗
PubMed2000

DNA damage by 5-aminolevulinic and 4,5-dioxovaleric acids in the presence of ferritin.

Cellular accumulation of 5-aminolevulinic acid (ALA), the first specific intermediate of heme biosynthesis, is correlated in liver biopsy samples of acute intermittent porphyria affected patients with an increase in the occurrence of hepatic cancers and the formation of ferritin deposits in hepatocytes. 5-Aminolevulinic acid is able to undergo enolization and to be subsequently oxidized in a reaction catalyzed by iron complexes yielding 4,5-dioxovaleric acid (DOVA). The released superoxide radical (O(*-)(2)) is involved in the formation of reactive hydroxyl radical ((*)OH) or related species arising from a Fenton-type reaction mediated by Fe(II) and Cu(I). This leads to DNA oxidation. The metal catalyzed oxidation of ALA may be exalted by the O(*-)(2) and enoyl radical-mediated release of Fe(II) ions from ferritin. We report here the potentiating effect of ferritin on the ALA-mediated cleavage of plasmid DNA and the enhancement of the formation of 8-oxo-7, 8-dihydro-2'-deoxyguanosine (8-oxodGuo). Plasmid pBR322 was incubated with ALA and varying amounts of purified ferritin. DNA damage was assessed by gel electrophoresis analysis of the open and the linear forms of the plasmid from the native supercoiled structure. Addition of either the DNA compacting polyamine spermidine or the metal chelator ethylenediaminetetraacetic acid (EDTA) inhibited the damage. It was also shown that ALA in the presence of ferritin is able to increase the oxidation of the guanine moiety of monomeric 2'-deoxyguanosine (dGuo) and calf thymus DNA (CTDNA) to form 8-oxodGuo as inferred from high performance liquid chromatography (HPLC) measurements using electrochemical detection. The formation of the adduct dGuo-DOVA was detected in CTDNA upon incubation with ALA and ferritin. In a subsequent investigation, the aldehyde DOVA was also able to induces strand breaks in pBR322 DNA.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1980

Homologies among ribosomal RNA and messenger RNA genes in chloroplasts, mitochondria and E. coli.

Labelled chloroplast rRNAs from Spinacia oleracea were hybridized to restriction endonuclease digests of chloroplast DNA from Oenothera hookeri and Euglena gracilis, to mitochondrial DNA of Acanthamoeba castellanii, and to DNA of the E. coli rrn B operon in the transducing phage lambda rifd 18. The degree of homology is greatest for the 16S rRNA gene. Greater than 90% occurs between the two higher plant genes, 80% homology to the lower plant gene, 60%-70% homology to the bacterial gene, and 20% homology to the mitochondrial gene. The degree of hybridization varied considerably for the 23S and the 5S rRNA genes. Very high homology exists between the two higher plant genes, only about 50% homology for both the Euglena and bacterial genes, and no significant homology for the mitochondrial genes. These results show that any chloroplast (or E. coli) rRNA may be used as a probe to identify rRNA genes in other ctDNAs. Two RNA populations, each enriched for a different ctDNA-encoded mRNA, proved useful in the location of these genes on both higher plant ctDNAs. No significant hybridization was obtained using these probes to the Euglena ctDNA which seems to be too distantly related.

Amoeba↗
PubMed1990

Cytoplasmic male sterility in beta is associated with structural rearrangements of the mitochondrial DNA and is not due to interspecific organelle transfer.

Chloroplast (ct) and mitochondrial (mt) DNAs from four cytoplasmic male sterile (cms) and 22 normal fertile sugar beet lines and accessions of wild beets from the genus Beta have been compared with restriction analyses and Southern hybridizations. We have used restriction analyses of ctDNA as a phylogenetic marker to confirm the taxonomic relationships between the different cytoplasms. According to the ctDNA data, all four cms cytoplasms belong to the same taxonomic section, Beta. Restriction patterns of ct and mtDNA from fertile accessions produced analogous trees of similarity and showed a close correlation between the organellar DNA diversity and the accepted taxonomic classification of the species studied. However, the mt-DNA restriction profiles of the four cms types differed dramatically from each other and from those of all fertile accessions from the genus. No indication of cytoplasmic introgression was found in any of the four investigated cms types. Southern hybridization to mtDNA revealed variant genomic arrangements in the different fertile and cms cytoplasms, indicating that rearrangement of the mitochondrial genome is a common denominator to the different cms systems in Beta. It may, indeed, be a common property to spontaneously occurring cms in all or most species.

Chloroplasts↗
PubMed1997

A 7.5-kbp region of the maize (T cytoplasm) mitochondrial genome contains a chloroplast-like trnI (CAT) pseudo gene and many short segments homologous to chloroplast and other known genes.

The DNA sequence of a 7.5-kbp region from the maize cmsT mt genome was determined. Nucleotide-sequence analysis of this region reveals the presence of a ct-like trnI (CAT) gene, orf31 and orf48 which are respectively homologous to the trnI (CAT) gene in the maize and rice chloroplast genomes, and to orf28 and orf64 in the rice chloroplast genome. Northern-blot analysis indicates that the ct-like trnI (CAT) gene is likely to be a pseudo gene in the maize cmsT mt genome because it is not transcribed. A nucleotide-sequence homology search of this 7.5-kbp region reveals several short segments homologous to portions of chloroplast (ct), mitochondrial (mt) and other known genes. These segments range from 17 bp to 187 bp in length with homology from 71 to 100%. These observations also suggest that the transfer of DNA fragments from the ct genome to the mt genome may have occurred at different times during the evolution of the maize mt genome, and that multiple recombination events and rearrangements in both mt and ct genomes have occurred after the transfer of DNA fragments from the ct to the mt genome. A few segments were identified by their homology to be portions of genes from sources other than the ct genome. While it is known that large fragments of ctDNA have been transferred to maize mt genomes, this is the first report of the presence of numerous short ctDNA, or other foreign DNA segments, in the maize cmsT mt genome. These segments may provide valuable information regarding the evolution of plant mt genomes.

Base Sequence↗
PubMed2006

Divalent-metal-dependent nucleolytic activity of Cu, Zn superoxide dismutase.

The known action of Cu, Zn superoxide dismutase (holo SOD) that converts O2- to O2 and H2O2 plays a crucial role in protecting cells from toxicity of oxidative stress. However, the overproduction of holo SOD does not result in increased protection but rather creates a variety of unfavorable effects, suggesting that too much holo SOD may be injurious to the cells. In the in vitro study, we report a finding that the holo SOD from bovine erythrocytes and its apo form possess a divalent-metal-dependent nucleolytic activity, which was confirmed by UV-vis absorption titration of calf thymus DNA (ctDNA) with the holo SOD, quenching of holo SOD intrinsic fluorescence by ctDNA, and by gel electrophoresis monitoring conversion of DNA from the supercoiled DNA to nicked and linear forms, and fragmentation of a linear lambdaDNA. Moreover, the DNA cleavage activity was examined in detail under certain reaction conditions. The steady-state study indicates that DNA cleavage supported by both forms of SOD obeys Michaelis-Menten kinetics. On the other hand, the assays with some other proteins indicate that this new function is specific to some proteins including the holo SOD. Therefore, this study reveals that the divalent-metal-dependent DNA cleavage activity is an intrinsic property of the holo SOD, which is independent of its natural metal (copper and zinc) sites, and may provide an alternative insight into the link between SOD enzymes and neurodegenerative disorders.

Animals↗
PubMed1996

8-Arylguanine adducts from arenediazonium ions and DNA.

Arenediazonium ions (ArN2+) are genotoxic though the source of their genotoxicity is unknown. The present studies were undertaken to determine if reductive decomposition of ArN2+ to aryl radicals (Ar) in the presence of calf thymus DNA (ctDNA) or in cells results in the formation of DNA adducts. We found that when arenediazonium ions of the general structure p-X-ArN2+ (X = CH3, CH2OCH3, CH2OH) are allowed to react with ctDNA or incubated with cells under conditions that produce p-X-Ar, DNA adducts are formed with guanine. The structure of the adduct is the C8-substitution product derived from guanine and p-X-Ar. Formation of p-X-Ar was determined by ESR spin-trapping with 5,5-dimethyl-1-pyrroline N-oxide (DMPO). The extent of C8-arylguanine adduction was measured by high performance liquid chromatography (HPLC) analysis of the DNA hydrosylate and comparison with authentic synthetic standards. The C8-arylguanine adducts observed to form may be important in regard to the genotoxicity of ArN2+, though other DNA adducts such as the N6-triazene of adenine or C8-aryladenine adducts can form. Finally, though the formation of C8-arylguanine adducts from arenediazonium ions has been proposed, this is the first report demonstrating their formation in DNA.

Animals↗
PubMed1985

Chloroplast biosystematics: chloroplast DNA as a molecular probe.

The classification of plants has traditionally been dependent upon the comparative analysis of morphological and biochemical data. In this paper the use of molecular probe analysis of chloroplast DNA (ctDNA) is used to expand the data base used in taxonomic studies. Chloroplast DNA size, homogeneity, the global arrangement of ctDNA structure, gene content, gene cluster array and gene sequence determination are discussed as useful criteria in the analysis of phylogenetic relationships.

Base Sequence↗
PubMed2006

Direct binding of Cu(II)-complexes of oxicam NSAIDs with DNA backbone.

Drugs belonging to the non-steroidal anti-inflammatory drug group (NSAID) are not only used as anti-inflammatory and analgesic agents, but also exhibit chemopreventive and chemosuppressive effects on various cancer cell lines. They exert their anticancer effects by inhibiting both at the protein level and/or at the transcription level. Cu(II) complexes of these NSAIDs show better anti-cancer effects than the bare drugs. Considering the above aspects, it is of interest to see if Cu(II) complexes of these drugs can exert their effects directly at the DNA level. In this study, we have used UV-Vis spectroscopy to characterize the complexation between Cu(II) and two NSAIDs belonging to the oxicam group viz. piroxicam and meloxicam, both of which exhibit anticancer properties. For the first time, this study shows that, Cu(II)-NSAID complexes can directly bind with the DNA backbone, and the binding constants and the stoichiometry or the binding site sizes have been determined. Thermodynamic parameters from van't Hoff plots showed that the interaction of these Cu(II)-NSAID complexes with ctDNA is an entropically driven phenomenon. Circular dichroism (CD) spectroscopy showed that the binding of these Cu(II)-NSAIDs with ctDNA result in DNA backbone distortions which is similar for both Cu(II)-piroxicam and Cu(II)-meloxicam complexes. Competitive binding with a standard intercalator like ethidium bromide (EtBr) followed by CD as well as fluorescence measurements indicate that the Cu(II)-NSAID complexes could intercalate in the DNA.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2005

New luminescent terbium complex for the determination of DNA.

New terbium complexes of derivatives of 2-oxo-4-hydroxy-quinoline-3-carboxylic acid are reported, which are highly luminescent, water soluble and do not require luminescence enhancers. The triplet-state energy levels of the ligands, the relative quantum yields (QYs) and the excitation maxima of the respective terbium chelates were determined. The large luminescence enhancement of one of these complexes by nucleic acids was investigated and a mechanism of its interaction with DNA is proposed. The optimal conditions for determination of DNA are equal concentrations of Tb(3+) and ligand R(1) (C = 1 x 10(-6) M), pH 9.0. Under optimal conditions the luminescence intensity (RI) is proportional to the concentration of fish sperm DNA (fsDNA) or calf thymus DNA (ctDNA), respectively, within the range of 0.05-1.5 microg ml(-1). The detection limits were 10 ng ml(-1) for fsDNA and 12 ng ml(-1) for ctDNA.

Animals↗
PubMed1997

In vitro DNA crosslinking by Ledakrin, an antitumor derivative of 1-nitro-9-aminoacridine.

Using agarose gel electrophoresis we confirmed that Ledakrin is capable of incurring covalent crosslinking in pBR322 plasmid DNA and also in poly(dGdC) in the presence of a simple activating system containing DTT. The identification of adducts resulting from DNA crosslinking was carried out by 32P-post-labelling assay. We assumed that such adduct(s) should be brought about more readily with double-stranded than with single-stranded polynucleotides or nucleotides. Since our earlier experiments had shown that guanine is a major site of covalent binding of 1-nitroacridines, we compared DNA adduct formation by Ledakrin for ctDNA, dG-containing synthetic homopolymers and 3'-pdG. 32P-Post-labelling assay revealed two adduct spots that were enhanced in samples containing double-stranded substrates in which interstrand crosslinking between guanines was possible, namely ctDNA and poly(dGdC).

Animals↗
PubMed2003

Electrochemical determination of interaction parameters for DNA and mitoxantrone in an irreversible redox process.

Mitoxantrone (MXT), an anti-tumor antibiotic, shows irreversible electrochemical behavior at a waxed graphite electrode in a 0.05 M Tris-HCl buffer (pH 7.4) solution. The interaction between MXT and calf thymus DNA (ctDNA) in solution has been studied using cyclic voltammetry. An electrochemical equation suitable for examining the binding of irreversibly electroactive molecules to DNA is established. Determination of diffusion coefficients of both free and binding MXT (D(f), D(b)), the binding constant (K) and binding site size (s base pairs per molecule, bp) of MXT with DNA was performed on the basis of the equation. A nonlinear fit analysis of the experimental data yielded: D(f)=3.76 x 10(-5) cm(2)s(-1), D(b)=2.73 x 10(-7) cm(2)s(-1), K=8.7 x 10(9) cm(3)mol(-1), s=2.8 bp. The results demonstrate that MXT binds tightly to ctDNA and covers three base pairs. The anthraquinone of MXT, which is a planar heterocyclic ring, intercalates between the DNA's base pairs. The two aminoethylamino side-chains of the drug fit to the major groove reinforce the combination of MXT and DNA. The results show that MXT is a DNA intercalator with a high binding constant compared to those of other anthraquinones.

Animals↗
PubMed2004

Resonance Rayleigh scattering study of the reaction of nucleic acids with thionine and its analytical application.

Resonance Rayleigh scattering (RRS) of the thionine (TH)-nucleic acids system and its analytical application have been studied. In pH 2.2 acidic buffer medium, some nucleic acids can react with TH to form TH-nucleic acids complex. This results in a great enhancement of RRS and the appearance of new RRS spectra. The RRS spectral characteristics of TH-ctDNA system, the affecting factors and the optimum conditions of the reaction have been investigated. The enhancement of the RRS signal is directly proportional to the concentration of nucleic acids in the range 0-10.0 microg/ml for calf thymus DNA and 0-15.0 microg/ml for yeast RNA, and its detection limits (3sigma) are 3.5 ng/ml for calf thymus DNA and 4.9 ng/ml for yeast RNA, respectively. The method shows a wide linear range and high sensitivity, and was applied to the determination of trace amounts of nucleic acid in synthetic samples and practical samples with satisfactory results. The bind properties for the interactions of TH with ctDNA were investigated using a Scatchard plot based on the measurement of the enhanced RRS data at 340 nm, and the binding number and intrinsic binding constant are 4.9 and 2.6 x 10(5) mol/dm(3), respectively.

Calibration↗
PubMed2000

4-Hydroxy-2-nonenal and ethyl linoleate form N(2),3-ethenoguanine under peroxidizing conditions.

In these studies, we demonstrate that N(2),3-ethenoguanine (N(2), 3-epsilonGua) is formed from lipid peroxidation as well as other oxidative reactions. Ethyl linoleate (EtLA) or 4-hydroxy-2-nonenal (HNE) was reacted with dGuo in the presence of tert-butyl hydroperoxide (t-BuOOH) for 72 h at 50 degrees C. The resulting N(2), 3-epsilonGua was characterized by liquid chromatography/electrospray mass spectroscopy and by gas chromatography/high-resolution mass spectral (GC/HRMS) analysis of its pentafluorobenzyl derivative following immunoaffinity chromatography purification. The amounts of N(2),3-epsilonGua formed were 825 +/- 20 and 1720 +/- 50 N(2), 3-epsilonGua adducts/10(6) normal dGuo bases for EtLA and HNE, respectively, corresponding to 38- and 82-fold increases in the amount of N(2),3-epsilonGua compared to controls containing only t-BuOOH. Controls containing t-BuOOH but no lipid resulted in a >1000-fold increase in the level of N(2),3-epsilonGua over dGuo that was not subjected to incubation. EtLA and HNE, in the presence of t-BuOOH, were reacted with calf thymus DNA at 37 degrees C for 89 h. The amounts of N(2),3-epsilonGua formed in intact ctDNA were 114 +/- 32 and 52.9 +/- 16.7 N(2),3-epsilonGua adducts/10(6) normal dGuo bases for EtLA and HNE, respectively. These compared to 2.02 +/- 0. 17 and 2.05 +/- 0.47 N(2),3-epsilonGua adducts/10(6) normal dGuo bases in control DNA incubated with t-BuOOH, but no lipid. [(13)C(18)]EtLA was reacted with dGuo to determine the extent of direct alkylation by lipid peroxidation byproducts. These reactions resulted in a 89-93% level of incorporation of the (13)C label into N(2),3-epsilonGua when EtLA and dGuo were in equimolar concentrations, when EtLA was in 10-fold molar excess, and when deoxyribose (thymidine) was in 10-fold molar excess. Similar reactions with ctDNA resulted in an 86% level of incorporation of the (13)C label. These data demonstrate that N(2),3-epsilonGua is formed from EtLA and HNE under peroxidizing conditions by direct alkylation. The data also suggest, however, that N(2),3-epsilonGua is also formed by an alternative mechanism that involves some other oxidative reaction which remains unclear.

Aldehydes↗
PubMed1975

Chloroplast DNA from higher plants replicates by both the Cairns and the rolling circle mechanism.

The chloroplast DNA (ctDNA) from pea and corn plants contains both Cairns type and rolling circle replicative intermediates. Denaturation mapping studies with pea ctDNA molecules have shown that the rolling circles initiate replication at or near the site where the Cairns replicative intermediates terminate replication. These results suggest that the rolling circles are initiated by a Cairns round of replication. A model for the replication of the chloroplast DNA is based on these results.

Chloroplasts↗
PubMed2000

Interactions of Janus Green B with double stranded DNA and the determination of DNA based on the measurement of enhanced resonance light scattering.

A novel assay of DNA with a sensitivity at the nanogram level is proposed based on the measurement of enhanced resonance light scattering (RLS) signals resulting from the interaction of Janus Green B (JGB) with DNA. At pH 6.37 and ionic strength < 0.20, the RLS signals of JGB were greatly enhanced by DNA in the region of 300-650 nm characterized by three peaks at 416.0, 452.0 and 469.2 nm. The binding properties were examined using a Scatchard plot based on the measurement of the enhanced RLS data at 416.0 nm at a high JGB: DNA molar ratio (R > 2.22), and an aggregation mechanism of JGB in the presence of DNA at the nanogram level is proposed. Linear relationships can be established between the enhanced RLS intensity and DNA concentration in the range 0-3.5 micrograms ml-1 for both calf thymus DNA (ctDNA) and fish sperm DNA (fsDNA) if 2.0 x 10(-5) M JGB is employed. The limits of determination were 8.7 ng ml-1 for ctDNA and 9.9 ng ml-1 for fsDNA, respectively. Synthetic samples were analysed satisfactorily.

Azo Compounds↗
PubMed2002

A sensitive and selective assay of nucleic acids by measuring enhanced total internal reflected resonance light scattering signals deriving from the evanescent field at the water/tetrachloromethane interfacet.

A total internal reflected resonance light scattering (TIR-RLS) technique, the coupling of resonance light scattering (RLS) technique with total internal reflected light at the interface of two immiscible liquids, where the steep change of the refractive indexes occurs to result in an evanescent field, is proposed with the characteristics of separation and enrichment properties of analytes and direct use of oil-soluble reagents free from surfactants. At pH 8.69 and ion strength 0.008, ternary amphiphilic species formed by the interaction of nucleic acids, including calf thymus DNA (ctDNA), fish sperm DNA (fsDNA), and yeast RNA (yRNA), with Eu(III) in the presence of oil-soluble trioctylphosphine oxide (TOPO), are adsorbed to the water/tetrachloromethane (H20/CCl4) interface, giving rise to significantly enhanced TIR-RLS signals. It has been found that the enhanced TIR-RLS intensity at 348.0 nm is proportional to the concentration of thermally denatured ctDNA, fsDNA and yRNA in the range 0.002-2.5 microg ml(-1), 0.002-2.5 microg ml(-1) and 0.003-2.0 microg ml(-1), respectively and their limits of determination (3sigma) are 0.16 ng ml(-1), 0.19 ng ml(-1) and 0.28 ng ml(-1), correspondingly. Complicated artificial samples with highly interfering backgrounds were determined satisfactorily.

Nucleic Acids↗
PubMed1997

Plasmon analyses of Triticum (wheat) and Aegilops: PCR-single-strand conformational polymorphism (PCR-SSCP) analyses of organellar DNAs.

To investigate phylogenetic relationships among plasmons in Triticum and Aegilops, PCR-single-strand conformational polymorphism (PCR-SSCP) analyses were made of 14.0-kb chloroplast (ct) and 13. 7-kb mitochondrial (mt)DNA regions that were isolated from 46 alloplasmic wheat lines and one euplasmic line. These plasmons represent 31 species of the two genera. The ct and mtDNA regions included 10 and 9 structural genes, respectively. A total of 177 bands were detected, of which 40.6% were variable. The proportion of variable bands in ctDNA (51.1%) was higher than that of mtDNA (28. 9%). The phylogenetic trees of plasmons, derived by two different models, indicate a common picture of plasmon divergence in the two genera and suggest three major groups of plasmons (Einkorn, Triticum, and Aegilops). Because of uniparental plasmon transmission, the maternal parents of all but one polyploid species were identified. Only one Aegilops species, Ae. speltoides, was included in the Triticum group, suggesting that this species is the plasmon and B and G genome donor of all polyploid wheats. ctDNA variations were more intimately correlated with vegetative characters, whereas mtDNA variations were more closely correlated with reproductive characters. Plasmon divergence among the diploids of the two genera largely paralleled genome divergence. The relative times of origin of the polyploid species were inferred from genetic distances from their putative maternal parents.

Journal Article↗