EVOLUTION IN THE GENUS AVENA: INHERITANCE OF DIFFERENT FORMS OF RIBULOSE DIPHOSPHATE CARBOXYLASE

1975 ◽  
Vol 17 (3) ◽  
pp. 337-344 ◽  
Author(s):  
M. W. Steer

Disc electrophoresis of ribulose diphosphate carboxylases from Avena species in polyacrylamide gels of varying concentrations reveals the presence of two distinct forms of the enzyme. One migrates faster than the other and is found exclusively in species possessing the A genome. The other is confined to the C genome species (A. pilosa, A. ventricosa, A. clauda). The association of another characteristic of this enzyme (presence of stromacentres in the chloroplasts) with the A genome was reported previously. Observations on the recently described species A. prostrata, A. canariensis, A. damascena, and A. murphyi show that they all possess stromacentres, confirming reports that they all contain the A genome. Examination of amphiploid hybrids (from crosses between various diploid species and A. sativa) has shown that the mobility character is inherited maternally, and is located on the chloroplast genome. All these hybrids have the A genome and all have stromacentres. The results are discussed in the light of recent findings on the structure and synthesis of this enzyme. Consideration of the species distribution of the different forms of carboxylase places certain restrictions on the possible evolutionary paths from diploids to tetraploids and hexaploids.

1972 ◽  
Vol 14 (3) ◽  
pp. 581-589 ◽  
Author(s):  
Iris L. Craig ◽  
Beatrice E. Murray ◽  
Tibor Rajhathy

Leaf esterase patterns of natural populations of diploid, tetraploid and hexaploid Avena species were separated by disc electrophoresis. The zymotypes of the A genome diploids A. hirtula, A. strigosa and A. longiglumis differed from the C genome diploids A. pilosa and A. ventricosa. The tetraploids A. barbata, A. magna and A. murphyi had distinctive zymotypes. The A. barbata zymotype resembled the A genome diploids which supports the cytological evidence for homoeology between the genomes. Avena magna and A. murphyi were a combination of the A and C diploid patterns with A. murphyi resembling the C more than the A pattern. The zymotypes of the hexaploids A. sterilis and A. sativa revealed the expected A, C and AC genome ancestry. Band affinity ratings within and between genomic groups agreed with the cytological evidence and cross-compatible relationships, the exception being the C — AC species that have high affinity ratings but are apparently cross-incompatible.


Genome ◽  
1996 ◽  
Vol 39 (3) ◽  
pp. 535-542 ◽  
Author(s):  
Concha Linares ◽  
Juan González ◽  
Esther Ferrer ◽  
Araceli Fominaya

A physical map of the locations of the 5S rDNA genes and their relative positions with respect to 18S–5.8S–26S rDNA genes and a C genome specific repetitive DNA sequence was produced for the chromosomes of diploid, tetraploid, and hexaploid oat species using in situ hybridization. The A genome diploid species showed two pairs of rDNA loci and two pairs of 5S loci located on both arms of one pair of satellited chromosomes. The C genome diploid species showed two major pairs and one minor pair of rDNA loci. One pair of subtelocentric chromosomes carried rDNA and 5S loci physically separated on the long arm. The tetraploid species (AACC genomes) arising from these diploid ancestors showed two pairs of rDNA loci and three pairs of 5S loci. Two pairs of rDNA loci and 2 pairs of 5S loci were arranged as in the A genome diploid species. The third pair of 5S loci was located on one pair of A–C translocated chromosomes using simultaneous in situ hybridization with 5S rDNA genes and a C genome specific repetitive DNA sequence. The hexaploid species (AACCDD genomes) showed three pairs of rDNA loci and six pairs of 5S loci. One pair of 5S loci was located on each of two pairs of C–A/D translocated chromosomes. Comparative studies of the physical arrangement of rDNA and 5S loci in polyploid oats and the putative A and C genome progenitor species suggests that A genome diploid species could be the donor of both A and D genomes of polyploid oats. Key words : oats, 5S rDNA genes, 18S–5.8S–26S rDNA genes, C genome specific repetitive DNA sequence, in situ hybridization, genome evolution.


1972 ◽  
Vol 14 (2) ◽  
pp. 305-316 ◽  
Author(s):  
H. C. Dass

Thin-layer chromatographic studies on flavonoids, and disc electrophoretic studies on proteins and esterase isoenzymes were conducted with Avena to determine species relationships and genome homologies. Distinctness of Avena ventricosa and A. pilosa was observed in comparison to other diploid species. Closeness of the diploid species of the A. strigosa group (including hirtula and wiestii) was evident from the similarity of their protein and esterase spectra. The tetraploid species, A. barbata and A. abyssinica, were found to be very close to A. hirtula and A. strigosa, respectively, by TLC studies. Proteins and esterases also showed that the tetraploid species are very close to the A. strigosa group of diploid species. The contribution of a genome by the A. strigosa group to the tetraploids and hexaploids was confirmed. The hexaploids showed different protein and esterase patterns. The involvement of A. ventricosa as the C genome donor to the hexaploids was shown by the protein and esterase spectra. A few extra protein bands observed may have been from the D genome.


Genome ◽  
2016 ◽  
Vol 59 (3) ◽  
pp. 209-220 ◽  
Author(s):  
Honghai Yan ◽  
Sara L. Martin ◽  
Wubishet A. Bekele ◽  
Robert G. Latta ◽  
Axel Diederichsen ◽  
...  

Genome size is an indicator of evolutionary distance and a metric for genome characterization. Here, we report accurate estimates of genome size in 99 accessions from 26 species of Avena. We demonstrate that the average genome size of C genome diploid species (2C = 10.26 pg) is 15% larger than that of A genome species (2C = 8.95 pg), and that this difference likely accounts for a progression of size among tetraploid species, where AB < AC < CC (average 2C = 16.76, 18.60, and 21.78 pg, respectively). All accessions from three hexaploid species with the ACD genome configuration had similar genome sizes (average 2C = 25.74 pg). Genome size was mostly consistent within species and in general agreement with current information about evolutionary distance among species. Results also suggest that most of the polyploid species in Avena have experienced genome downsizing in relation to their diploid progenitors. Genome size measurements could provide additional quality control for species identification in germplasm collections, especially in cases where diploid and polyploid species have similar morphology.


Botany ◽  
2013 ◽  
Vol 91 (3) ◽  
pp. 167-175 ◽  
Author(s):  
Alicia López ◽  
Aveliano Fernández ◽  
Joel S. Shore

We explore the evolution of polyploids in subseries Turnera, testing hypotheses on their origins using DNA sequences (partial ndhF and trnT-L) from the plastid genome, as well as sequences of the nuclear ribosomal internal transcribed spacer (ITS). We construct phylogenies (with both Bayesian and maximum parsimony methods) using both the plastid and ITS sequences. We test hypotheses concerning the genome contributors to polyploids where previous cytogenetic studies had designated various diploid species as possessing A or C genomes and had proposed various genomic constitutions for the polyploids. Our analyses support the occurrence of a C genome clade of species and the origin of autooctoploid T. fernandezii Arbo from T. grandiflora (Urb.) Arbo (a C genome diploid). Nuclear ITS data support the hypothesis that T. concinna Arbo (an A genome species) contributed a genome to the segmental allotetraploid T. grandidentata (Urb.) Arbo, whereas analyses of ndhF and trnT-L sequences did not lead to identification of the plastid (or additional nuclear genome) donor. Our analyses support the origins of allooctoploids T. aurelii Arbo and T. cuneiformis Poir. from hexaploid T. orientalis (Urb.) Arbo. We found no evidence that hexaploid T. velutina Presl. possesses a C genome. We provide evidence, using Bayes factors, supporting the hypothesis that the segmental allohexaploids have had independent origins.


Genome ◽  
1995 ◽  
Vol 38 (6) ◽  
pp. 1279-1284 ◽  
Author(s):  
Rita Alicchio ◽  
Lina Aranci ◽  
Lucia Conte

We report a molecular approach to the study of the phylogenetic relationships of Avena diploid and polyploid species based on RFLP detected with three cDNA probes of nuclear genes belonging to multigenic families (low pI α-amylase, avenin, and globulin). All the probes were highly informative in the detection of polymorphism between oat species. Associations between species were determined from cluster (UPGMA) analysis based on distance values calculated from RFLP data separately for each of the two levels of ploidy. Results were in general agreement with morphology based phylogenetic analyses, confirming the large differentiation among A and C genomes in the evolution of diploid species and the genetic homogeneity among A. brevis, A. strigosa, and A. nuda and the recently discovered A. atlantica. A certain divergence was observed between two endemic species (A. canariensis and A. damascena) and the other diploid species with the A genome. The analysis of tetraploid species relationships confirms the differentiation of the barbata complex (A. wiestii, A. barbata, A. abyssinica, and A. vaviloviana) from the maroccana–murphyi–agadiriana group, which, despite some similarities in morphological and biochemical traits, seems to have accumulated deep genetic differences along its evolutionary pathway.Key words: Avena genomes, genetic distance, ploidy, RFLP, multigenic families.


Genome ◽  
1988 ◽  
Vol 30 (5) ◽  
pp. 627-632 ◽  
Author(s):  
A. Fominaya ◽  
C. Vega ◽  
E. Ferrer

Giemsa C-banding was used to identify individual somatic chromosomes in eight diploid species of Avena. Two patterns of heterochromatin distribution were found. The chromosomes of five A genome species (A. strigosa, A. hirtula, A. longiglumis, A. damascena, and A. canariensis) possessed mainly telomeric bands, whereas those from three C genome species (A. clauda, A. pilosa, and A. ventricosa) were characterized by higher chromatin condensation and several intercalary heterochromatin bands. The divergent evolution between the two groups is confirmed after C-banding. The unique C-banding patterns of several chromosomes in each species will be a useful tool for the study of meiotic behaviour in interspecific hybrids among Avena spp.Key words: C-banding, Avena, heterochromatin.


1984 ◽  
Vol 26 (6) ◽  
pp. 698-700 ◽  
Author(s):  
J. M. Leggett

Alloplasmic lines involving the nuclear genomes of the hexaploid oat Avena sativa, the cytoplasms of the diploid species A. canariensis, A. hirtula, A. pilosa, A. prostrata, and A. ventricosa, and the tetraploid A. barbata have been produced. The cytoplasmic effects on growth rate and flowering date are described with particular reference to the introduction of the cytoplasm from the two C-genome diploid species.Key words: Avena, quantitative inheritance, cytoplasmic effects.


1972 ◽  
Vol 14 (3) ◽  
pp. 645-654 ◽  
Author(s):  
Tibor Rajhathy ◽  
B. R. Baum

A new diploid species of oat from Syria, named Avena damascena Rajhathy et Baum, is described. It has some macro- and micromorphological similarities to A. wiestii and A. prostrata, both diploids, and to tetraploid A. barbata. It differs from one or the other of them in its lemma tips, lodicules, epiblast and in the unique structure of the cuticle on the glumes. Avena damascena has a distinct symmetrical karyotype, designated Ad. The karyotype of A. prostrata is designated Ap. Avena damascena is isolated from A. prostrata by hybrid sterility and from the other diploids by cross-incompatibility. Avena damascena and A. prostrata are considered relicts of a common population because they retain a high degree of genome homology. Their chromosomes differ by two interdependent interchange complexes which led to a pollen sterility. Genome relationships in the A genome group of diploids are briefly discussed in terms of meiotic pairing patterns and karyotypes.


1977 ◽  
Vol 23 (2) ◽  
pp. 229-233 ◽  
Author(s):  
L L Gershbein ◽  
K G Raikoff

Abstract Toward delineation of changes in total lactate dehydrogenase (LDH) and in the distribution of LDH isoenzymes as assessed by polyacrylamide disc electrophoresis, we inbucated human and rat sera with various agents, notably sulfhydryl compounds. Although artefacts were apparent when these agents were used without preliminary adjustment of pH, we saw little alteration in total unitage when one or two volumes of serum was mixed with one volume of any of several thiols, especially penicillamine, at an initial concentration of 0.4 mol/liter and pH 7.0-7.5. Under these conditions, penicillamine caused a loss in LDH-5 after incubation for 1 h at 25 degrees C together with small decreases in mobility of the other four isoenzymes toward the anode. A zymosan region appeared below the albumin and tracking dye area. With longer periods of incubation of rat serum with penicillamine or alpha-mercaptosuccinate, a novel band in the zymogram was noted just above the LDH-4 peak. The observations are discussed in terms of allosteric effectors.


Sign in / Sign up

Export Citation Format

Share Document