The interspecific and evolutionary relationships of Triticum ovatum

Genome ◽  
1988 ◽  
Vol 30 (2) ◽  
pp. 218-221 ◽  
Author(s):  
Gordon Kimber ◽  
P. J. Sallee ◽  
M. M. Feiner
Keyword(s):  
Genome Analysis ◽  
Evolutionary Relationships ◽  
New Combinations ◽  
Diploid Progenitor ◽  
Meiotic Analysis ◽  
Theory Of Evolution ◽  
Substantial Modification ◽  
Wheat Group ◽  
M Genome

Meiotic analysis of 13 hybrids, 3 of which are new combinations, shows that the M genome of Triticum ovatum has undergone substantial modification. The pivotal U genome is much closer to its diploid progenitor, Triticum umbellulatum. However, the possibility exists that it too has been somewhat modified. If this is substantiated, then some reconsideration of the pivotal–differential theory of evolution in the wheat group may be required.Key words: genome analysis, meiosis, Aegilops, wheat.

The genus Relicinopsis is nested within Relicina (Parmeliaceae, Ascomycota)

2017 ◽  
Vol 49 (3) ◽  
pp. 189-197 ◽  
Author(s):  
Paul M. KIRIKA ◽  
Pradeep K. DIVAKAR ◽  
Steven D. LEAVITT ◽  
Kawinnat BUARUANG ◽  
Ana CRESPO ◽  
...  
Keyword(s):  
Ribosomal Dna ◽  
Dna Sequences ◽  
Alternative Hypothesis ◽  
Morphological Features ◽  
Evolutionary Relationships ◽  
New Combinations ◽  
Hypothesis Tests ◽  
Phylogenetic Framework ◽  
Phenotypic Features

AbstractMacro-morphological features traditionally used to segregate genera in Parmeliaceae have been shown to be highly plastic, placing limits on their taxonomic value. Here we aim to elucidate the evolutionary relationships of the genera Relicina and Relicinopsis and reassess the phenotypic features traditionally used to separate these genera. To this end, we gathered ribosomal DNA sequences of ITS, nuLSU and mtSSU and analyzed them in a phylogenetic framework. Relicina was recovered as paraphyletic, with Relicinopsis nested within, and three different clades were identified within Relicina. Alternative hypothesis tests significantly rejected the monophyly of Relicina. Our results indicate that the presence or absence of bulbate cilia is of limited taxonomic value in this clade. Based on differences in conidia, however, we propose to accept Relicinopsis as a subgenus within Relicina as Relicina subgen. Relicinopsis (Elix & Verdon) Kirika, Divakar & Lumbsch. It is proposed that five new combinations of species previously classified in Relicinopsis be placed in Relicina.

Hybrids involving wheat relatives and autotetraploid Triticum umbellulatum

Genome ◽  
1989 ◽  
Vol 32 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Gordon Kimber ◽  
Yang Yen
Keyword(s):  
Numerical Methods ◽  
Chromosome Pairing ◽  
Genome Analysis ◽  
Reliable Method ◽  
Genomic Analysis ◽  
Conclusive Evidence ◽  
Diploid Progenitor ◽  
Substantial Evidence ◽  
Evolutionary Pathways ◽  
Specific Pairing

Genomic analysis based on chromosome pairing is perhaps the most reliable method of determining the major evolutionary pathways in allopolyploid series. Difficulties can arise when genomes have become modified, since then they will not correspond exactly to the genomes used as analysers. Some resolution of this type of problem is possible when the interpretation of meiotic data is enhanced by numerical methods. However, providing conclusive evidence of which chromosomes are pairing rather than just how many remains a problem unless specific chromosomes can be recognized. One possible solution is to make hybrids between natural polyploids and autotetraploids of the putative diploid progenitors. The recognition of specific pairing patterns in such hybrids will provide substantial evidence of which chromosomes are pairing at metaphase I. Hybrids between an autotetraploid Triticum umbellulatum and the natural U-genome polyploids T. kotschyi, T. neglecta, T. ovatum, T. macrochaetum, T. columnare, T. triunciale, and T. juvenale demonstrate that the U-genome of most of them is very closely related to the U-genome of the diploid T. umbellulatum. The U-genome in four hybrids in two accessions of T. ovatum does differ from its diploid progenitor, T. columnare shows some heterogeneity, and T. juvenale may show differentiation.Key words: autotetraploid, evolution, genome analysis, Triticum species, pivotal–differential evolution.

Genomic relationships of N-genome Triticum species

Genome ◽  
1992 ◽  
Vol 35 (6) ◽  
pp. 962-966 ◽  
Author(s):  
Yang Yen ◽  
Gordon Kimber
Keyword(s):  
Genome Analysis ◽  
Polyploid Species ◽  
D Genome ◽  
The Third ◽  
Triticum Species ◽  
Genomic Relationships ◽  
M Genome

Induced autotetraploids of Triticum uniaristatum, T. tauschii, and T. umbellulatum were used to study the genomes of the polyploid species T. ventricosum, T. neglecta, and T. recta. The N genome in T. ventricosum is homologous to the N genome in the putative diploid donor T. uniaristatum and has undergone little modification. The D genome in T. ventricosum is also essentially unmodified. The U genome of T. neglecta appears to be unchanged from the U genome of T. umbellulatum. Two of the genomes of T. recta are the same as the genomes in T. neglecta (U and a presumed modified M genome). The presence of a U genome in T. recta has also been independently confirmed. The origin of the third genome in T. recta has not been confirmed.Key words: chromosomes, meiosis, genome analysis, wheat.

A model of meiotic chromosome association in triploids

Genome ◽  
1989 ◽  
Vol 32 (1) ◽  
pp. 82-98 ◽  
Author(s):  
Charles F. Crane ◽  
David A. Sleper
Keyword(s):  
Genome Analysis ◽  
Meiotic Chromosome ◽  
A Priori ◽  
Chiasma Formation ◽  
Chromosome Association ◽  
Subsequent Formation ◽  
Meiotic Analysis ◽  
Partner Exchange ◽  
Translocation Heterozygosity ◽  
Metaphase I

A model was developed for chromosome association at meiotic metaphase I in triploids. Probabilities were estimated for each pachytene configuration and for subsequent formation of at least one chiasma in each combination of chromosome arms. Long and short arms were allowed to differ, but were related through an effective arm ratio so that the pattern of genomic affinity was the same for both arms. No other a priori assumptions were made about the pattern of genomic affinity. However, the usual assumptions of genome analysis were made including the following: identity of genomic-affinity pattern and chiasma frequency across homeologous groups, freedom from translocation heterozygosity, independence of chromosome arms, and absence of chiasma formation on both sides of a synaptic partner exchange within an arm. The model was statistically overparameterized and, therefore, had multiple solutions that yielded the same expected meiotic analysis. The range of these solutions can be found through repeated optimizations from randomly chosen starting values within the permitted ranges of the variables. It was convenient to express the optimized pattern of genomic affinity in terms of the proportions of metaphase I association due to each pairwise combination of genomes. Genomic affinity was analyzed in 16 triploid hybrids with the aid of the model.Key words: polyploidy, genome analysis, meiotic model.

scholarly journals Polyphyly of the genus Canoparmelia—uncovering incongruences between phenotype-based classification and molecular phylogeny within lichenized Ascomycota (Parmeliaceae)

Phytotaxa ◽  
2016 ◽  
Vol 289 (1) ◽  
pp. 36 ◽  
Author(s):  
PAUL M. KIRIKA ◽  
PRADEEP K. DIVAKAR ◽  
ANA CRESPO ◽  
STEVEN D. LEAVITT ◽  
GEORGE MUGAMBI ◽  
...  
Keyword(s):  
Molecular Phylogeny ◽  
Phylogenetic Analyses ◽  
Morphological Features ◽  
Evolutionary Relationships ◽  
New Combinations ◽  
Sister Relationship ◽  
Rdna Sequences ◽  
Taxonomic Changes ◽  
Phylogenetic Framework ◽  
Clade 1

Many phenotypical features traditionally used to classify genera in Parmeliaceae and in lichens in general have evolved several times independently, potentially limiting their taxonomic utility. Here, we aim to elucidate evolutionary relationships of Canoparmelia s. lat. among other parmotremoid taxa. A multilocus dataset (ITS, nuLSU and mtSSU rDNA sequences) was gathered and analyzed within a phylogenetic framework. Canoparmelia s. lat. was recovered as highly polyphyletic within the parmelioid clade, and three divergent lineages representing Canoparmelia s. lat. were identified in addition to the previously segregated Crespoa group. Of these, two formed a sister relationship with Parmotrema. However, no apparent diagnostic morphological features were found distinguishing the distinct Canoparmelia s. lat. clades reconstructed in the phylogenetic analyses. As a consequence, we propose to restrict the circumscription of Canoparmelia to clade 1 (i.e. the C. texana group) and to include clades 2 and 3 in Parmotrema. We propose to recognize these well-supported monophyletic clades at subgeneric level. Consequently, the new subgeneric name Parmotrema subgen. Africanae is proposed for clade 3 recovered in this study. Since clade 4, which clusters with the genera Nesolechia and Punctelia, is only represented by a single sequenced specimen, we refrain from proposing any taxonomic changes. The new combinations Parmotrema epileucum, and P. zimbabwense are proposed.

The use of cell culture for subchromosomal introgressions of barley yellow dwarf virus resistance from Thinopyrum intermedium to wheat

Genome ◽  
1995 ◽  
Vol 38 (2) ◽  
pp. 395-405 ◽  
Author(s):  
P. M. Banks ◽  
P. J. Larkin ◽  
H. S. Bariana ◽  
E. S. Lagudah ◽  
R. Appels ◽  
...  
Keyword(s):  
Cell Culture ◽  
Barley Yellow Dwarf Virus ◽  
Yellow Dwarf ◽  
Dwarf Virus ◽  
Polymorphism Analysis ◽  
Meiotic Analysis ◽  
Barley Yellow Dwarf ◽  
Wheat Group ◽  
Yellow Dwarf Virus ◽  
Alien Chromatin

Barley yellow dwarf virus (BYDV) resistance has been transferred to wheat from a group 7 chromosome of Thinopyrum (Agropyron) intermedium. The source of the resistance gene was the L1 disomic addition line, which carries the 7Ai-1 chromosome. The resistance locus is on the long arm of this chromosome. BYDV resistant recombinant lines were identified after three or more generations of selection against a group 7 Th. intermedium short arm marker (red coleoptile) and selection for the presence of BYDV resistance. One recombinant line produced by ph. mutant induced homoeologous pairing and 14 recombinant lines induced by cell culture have been identified. Resistance in seven of the cell culture induced recombinants has been inherited via pollen according to Mendelian segregation ratios for up to eight generations. Meiotic analysis of heterozygotes indicates that the alien chromatin in the cell culture induced recombinants is small enough to allow regular meiotic behaviour. The ph-induced recombinant was less regular in meiosis. A probe, pEleAcc2, originally isolated from Th. elongatum and that hybridizes to dispersed repeated DNA sequences, was utilised to detect Th. intermedium chromatin, which confers resistance to BYDV, in wheat backgrounds. Quantification of these hybridization signals indicated that the translocations involved a portion of alien chromatin that was smaller than the complete long arm of 7Ai-1. Restriction fragment length polymorphism analysis confirmed the loss of the short arm of 7Ai-1 and indicated the retention of segments of the long arm of 7Ai-1. Two 7Ai-1L DNA markers always assorted with the BYDV resistance. A third 7Ai-IL DNA marker was also present in seven of eight recombinants. In all recombinants except TC7, the 7Ai-1L markers replaced the 7DL markers. None of the wheat group 7 markers was missing from TC7. It is concluded that all the resistant lines are the result of recombination with wheat chromosome 7D, except line TC7, which is the result of recombination with an unidentified nongroup 7 chromosome.Key words: Triticum, Agropyron, alien genes, translocation, somatic recombination, luteovirus.

A synopsis of American Salix

1976 ◽  
Vol 54 (24) ◽  
pp. 2769-2789 ◽  
Author(s):  
Robert D. Dorn
Keyword(s):  
New Species ◽  
Evolutionary Relationships ◽  
New Combinations

The classification of American Salix (willows) is updated to account for nomenclatural changes, new species and sections, and new data. Evolutionary relationships, biology, and nomenclatural difficulties in the genus are briefly discussed. A preliminary, simplified key to sections is presented along with a synopsis of subgenera, sections, and subsections. One new section and two new subsections are described. Six new combinations are also made. The important literature is cited.

Sign in / Sign up

Export Citation Format

Share Document