Genome analysis of Elymus alatavicus and E. batalinii (Poaceae: Triticeae)

1986 ◽  
Vol 28 (5) ◽  
pp. 770-776 ◽  
Author(s):  
Kevin B. Jensen ◽  
Douglas R. Dewey ◽  
Kay H. Asay
Keyword(s):  
Chromosome Pairing ◽  
Genome Analysis ◽  
Taxonomic Classification ◽  
Meiotic Behaviour ◽  
Pseudoroegneria Spicata ◽  
Mode Of Reproduction ◽  
The Relationship ◽  
Partial Fertility ◽  
Metaphase I

Elymus alatavicus (Drob.) A. Love and E. batalinii (Krasn.) A. Love were studied to determine (i) meiotic behaviour, (ii) the mode of reproduction, (iii) the relationship between the two species, (iv) genomic constitutions, and (v) the most logical taxonomic classification of both species. A series of F1 hybrids between E. alatavicus, E. batalinii, and six "analyzer" species were developed. Chromosome pairing was studied at metaphase I to identify genomic similarities or differences. The results showed that E. alatavicus and E. batalinii are caespitose, self-fertile allohexaploids (2n = 42) with the same genomic formula SSYYXX. The F1 hybrids between E. alatavicus and E. batalinii had complete pairing (21 bivalents) at metaphase I in 7% of the cells and almost complete pairing in the remaining cells. High chromosome pairing and partial fertility (4 seeds/plant) in the F1 hybrids shows that the two species are closely related. Hybrids were obtained between E. alatavicus or E. batalinii and the following "analyzer" species with known genomic formulas: Pseudoroegneria spicata (Pursh) A. Love, 2n = 14, SS; P. cognata (Hack.) A. Love, 2n = 14, SS; E. lanceolatus (Scribn. &Smith) Gould, 2n = 28, SSHH; E. trachycaulus1 (Link) Gould ex Shinners, 2n = 28, SSHH; E. mutabilis (Drob.) Tzvelev, 2n = 28, SSHH; and E. drobovii (Nevski) Tzvelev, 2n = 42, SSHHYY. Chromosome pairing in this series of hybrids demonstrated that E. alatavicus and E. batalinii contain an S and probably a Y genome plus an unknown genome, X, that may have been derived from Psathryostachys huashanica Keng or from Agropyron. Elymus alatavicus and E. batalinii are correctly classified in the genus Elymus.Key words: cytotaxonomy, Agropyron, meiosis, chromosome.

Homology of chromosomes of the X genomes in common and Uruguayan dallisgrass, Paspalum dilatatum

Genome ◽  
1991 ◽  
Vol 34 (6) ◽  
pp. 950-953 ◽  
Author(s):  
Byron L. Burson
Keyword(s):  
Chromosome Pairing ◽  
Chromosome Numbers ◽  
The Other ◽  
Paspalum Dilatatum ◽  
Intraspecific Hybridization ◽  
The Common ◽  
Complete Sets ◽  
The Relationship ◽  
Metaphase I

Two biotypes of dallisgrass, Paspalum dilatatum Poir., designated common and Uruguayan, have chromosome numbers and genome formulas of 2n = 5x = 50 (IIJJX) and 2n = 6x = 60 (IIJJXX), respectively. The relationship between the X genomes in these two biotypes is unknown, and each was arbitrarily assigned the letter X to designate an unknown genome. This study was undertaken to determine the relationship between the X genomes in these two biotypes. Because both biotypes are apomicts and cannot be crossed, a sexual intraspecific F1 hybrid (2n = 45) between sexual yellow-anthered (2n = 4x = 40; IIJJ) and common dallisgrass biotypes was crossed with Uruguayan dallisgrass. This F1 hybrid has complete sets of the I and J genomes but only 5 of the 10 chromosomes of the X genome from common dallisgrass. Two hybrids were recovered. One had 52 and the other had 53 chromosomes, which associated at metaphase I as 22 bivalents + 8 univalents and 23 bivalents + 7 univalents, respectively. Twenty bivalents represent pairing of members of the I and J genomes, and those in excess of 20 represent pairing between members of the two X genomes. The remaining members of the X genome from the Uruguayan biotype were present as univalents at metaphase I. This demonstrates that those chromosomes of the X genome from the common biotype that were present are homologous to members of the X genome of the Uruguayan biotype. Both hybrids are aposporous facultative apomicts with some sterility.Key words: meiosis, intraspecific hybridization, chromosome pairing, genome relations, apomixis.

Chromosome pairing in triploid and tetraploid hybrids in Elytrigia (Triticeae; Poaceae)

1984 ◽  
Vol 26 (5) ◽  
pp. 519-522 ◽  
Author(s):  
Patrick E. McGuire
Keyword(s):  
Chromosome Pairing ◽  
Genome Analysis ◽  
Triploid Hybrid ◽  
Pollen Mother Cells ◽  
Tetraploid Hybrid ◽  
A Genome ◽  
Mother Cells ◽  
Metaphase I

Mean chromosome pairing of 5.14I + 1.28II (rod) + 3.86II (ring) + 1.47III + 0.11IV (open) + 0.11V was observed in pollen mother cells at metaphase I in the triploid hybrid Elytrigia scirpea (K. Presl) Holub, 2n = 4x = 28 × E. bessarabica (Savul. et Rayss) Dubrovik, 2n = 4x = 14. Mean chromosome pairing of 3.71I + 2.29II (rod) + 1.82II (ring) + 2.64III + 0.29IV (open) was observed in the triploid hybrid E. curvifolia (Lange) Holub, 2n = 4x = 28 × E. bessarabica. Mean chromosome pairing of 3.00I + 0.93II (rod) + 1.57II (ring) + 1.36III + 1.79IV (open) + 1.I4IV (closed) + 0.79V was observed in the tetraploid hybrid E. junceiformis Löve et Löve, 2n = 4x = 28 × E. curvifolia. The first hybrid provides the first evidence by genome analysis that E. bessarabica possesses a genome (designated Eb) which is closely related to the genomes of E. scirpea (ES and ESC) and hence to the E genome of E. elongata (Host) Nevski, 2n = 2x = 14. The second and third hybrids provide the first evidence that the two genomes of E. curvifolia (designated EC and ECU) are related to the Eb genome of E. bessarabica and thus to the E genome of E. elongata.Key words: Elytrigia, homoeology, Triticum, phylogeny, triploid, tetraploid.

What can genome analysis offer for bacteria?

2021 ◽  
pp. 255-281
Author(s):  
Markus Göker
Keyword(s):  
Polyphasic Taxonomy ◽  
Genome Analysis ◽  
Bacterial Species ◽  
Species Level ◽  
Taxonomic Classification ◽  
Taxon Sampling ◽  
Branch Support ◽  
Genome Scale

Abstract This book chapter is organized as follows: (i) the main approaches to the philosophy of taxonomic classification are recapitulated; (ii) the paradigm of polyphasic taxonomy is discussed in this context; (iii) the causes of conflict between previous classifications and genome-scale analyses are investigated, using examples from recent phylum-wide studies, with a discussion of how markers used in polyphasic taxonomy can be replaced by genome-derived ones; and (iv) the challenges in assigning taxonomic ranks using genome-scale or other data are revisited. The conclusion assesses the chances, or lack thereof, of reconciling taxonomic classifications. Phenetic and phylogenetic thinking still compete with each other on the classification of bacteria, with potentially conflicting and confusing results. Some causes of problematic taxonomic classifications are independent of the type and number of characters that can be used and can only be mitigated if, for example, taxon sampling and branch support are more appropriately taken into account. It may be possible to devise objective criteria for separating bacterial species, but the currently dominating approaches for microbial species delineation may be inadequate. It is even harder to delineate higher taxa; in contrast to claims in the literature, it may prove to be impossible to objectively assign taxonomic ranks above species level.

Amphidiploids of perennial Triticeae. I. Synthetic Thinopyrum species and their hybrids

Genome ◽  
1992 ◽  
Vol 35 (6) ◽  
pp. 951-956 ◽  
Author(s):  
Richard R.-C. Wang
Keyword(s):  
Gene Flow ◽  
Chromosome Pairing ◽  
Colchicine Treatment ◽  
Meiotic Pairing ◽  
Pseudoroegneria Spicata ◽  
Genomic Relationships ◽  
Thinopyrum Elongatum ◽  
Metaphase I

Amphiploids of the hybrid Thinopyrum elongatum (Host) D.R. Dewey (2n = 2x = 14; JeJe) × Pseudoroegneria spicata (Pursh) A. Löve (2n = 2x = 14; SS) were obtained by the colchicine treatment of regenerants from inflorescence culture. Meiotic pairings in the JJSS amphiploids averaged 2.90 I + 4.44 rod II + 7.50 ring II + 0.14 III + 0.20 IV at metaphase I but had 13.38 ring II + 0.30 IV at diakinesis. This amphidiploid was crossed with that of T. bessarabicum (Savul. &Rayss) A. Löve (2n = 2x = 14; JbJb) × T. elongatum and the latter was also crossed with T. scirpeum (K. Presl) D.R. Dewey (2n = 4x = 28; JeJeJeJe) to obtain JbJeJeS and JeJeJeJb hybrids, respectively. The former hybrid had a metaphase I pairing pattern of 7.82 I + 4.33 rod II + 2.76 ring II + 1.51 III + 0.35 IV. The latter hybrid had 3.04 I + 4.05 rod II + 4.31 ring II + 1.26 III + 1.08 IV. These meiotic pairing data are in agreement with the genomic relationships based on the diploid hybrids involving these genomes. Fertility of the hybrid between T. scirpeum and the amphiploid of T. bessarabicum × T. elongatum suggested that their genomes were similar and balanced and that gene flow could occur between the JJ diploids and the JJJJ tetraploid.Key words: hybrid, amphidiploid, genome, isozyme, chromosome pairing, Triticeae, Thinopyrum.

FERTILITY AND MEIOTIC BEHAVIOUR IN TETRAPLOID BARLEY

1975 ◽  
Vol 17 (1) ◽  
pp. 121-123 ◽  
Author(s):  
George Fedak
Keyword(s):  
Chromosome Pairing ◽  
Meiotic Behaviour ◽  
Preferential Pairing ◽  
Subsequent Fertility ◽  
Structural Differences ◽  
Hordeum Leporinum ◽  
Metaphase I

Chromosome pairing at metaphase I and distribution at anaphase I were examined in 3 autotetraploid and 3 amphidiploid parents and their F1 hybrids and related to spike fertility of the respective plants. Structural differences translocated from the Hordeum leporinum chromosomes to H. vulgare did not significantly enhance preferential pairing and subsequent fertility in the latter as anticipated. Quadrivalent formation was not related but regular disjunction at anaphase I was related to spike fertility.

FUSION OF CHROMOCENTERS IN PREMEIOTIC INTERPHASE OF SECALE CEREALE AND ITS POSSIBLE RELATIONSHIP TO CHROMOSOME PAIRING

1977 ◽  
Vol 19 (2) ◽  
pp. 313-321 ◽  
Author(s):  
J. G. Bowman ◽  
Tibor Rajhathy
Keyword(s):  
Chromosome Pairing ◽  
Secale Cereale ◽  
Disruptive Effect ◽  
Immature Inflorescence ◽  
Multivalent Formation ◽  
Relationship Of ◽  
The Relationship ◽  
Metaphase I

The premeiotic interphase of rye has been found to exhibit a synchronized fusion of chromocenters. This results in a solid knot of heterochromatin localized to one side of the nucleus. Colchicine injected into the immature inflorescence of diploid rye has been found to induce univalent and multivalent formation at metaphase I. The early premeiotic interphase was the phase of development most sensitive to colchicine. Colchicine was also found to have a similar disruptive effect on fusion of chromocenters in the premeiotic interphase. The relationship of these observations to chromosome pairing is discussed.

Cytology, fertility, and morphology of Elymus kengii (Keng) Tzvelev and E. grandiglumis (Keng) A. Löve (Triticeae: Poaceae)

Genome ◽  
1990 ◽  
Vol 33 (4) ◽  
pp. 563-570 ◽  
Author(s):  
Kevin B. Jensen
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrids ◽  
Central China ◽  
Psathyrostachys Huashanica ◽  
Pseudoroegneria Spicata ◽  
Polyploid Evolution ◽  
Mode Of Reproduction ◽  
Psathyrostachys Juncea ◽  
Glume Length ◽  
Elymus Lanceolatus

This study reports on the cytogenetics, fertility, mode of reproduction, and morphological variation of two perennial Triticeae grasses, Elymus kengii (Keng) Tzvelev and Elymus grandiglumis (Keng) A. Löve, from west central China. Both species are allohexaploids (2n = 42), self-fertile, and morphologically distinct on the basis of their plant color, glume length, and lemma and rachis vestiture. F1 hybrids between these two species are partially fertile and morphologically intermediate to their parents. Analysis of chromosome pairing in hybrids between E. grandiglumis or E. kengii and the following "analyzer" species, Psathyrostachys juncea (Fisch.) Nevski (NN), Psathyrostachys huashanica Keng (NN), Elymus lanceolatus (Scribn. &Smith) Gould (SSHH), Elymus dentatus (Hook. f.) Tzvelev ssp. ugamicus (Drob.) Tzvelev (SSYY), Elymus ciliaris (Trin.) Nevski (SSYY), Pseudoroegneria spicata (Pursh) A Löve (SS), and Pseudoroegneria tauri (Boiss. &Bal.) A. Löve (SSPP), suggested that both taxa contain the S, Y, and P genomes. This represents a new genome combination not previously reported and shows that the P genome from the crested wheatgrasses (Agropyron) has been involved in polyploid evolution within the. Triticeae.Key words: genome, meiosis, chromosome pairing, interspecific hybrids, Elymus, Triticeae.

K-MEANS CLUSTERING ALGORITHM BASED CLASSIFICATION OF SOIL FERTILITY IN NORTH WEST NIGERIA

2020 ◽  
Vol 4 (2) ◽  
pp. 780-787
Author(s):  
Ibrahim Hassan Hayatu ◽  
Abdullahi Mohammed ◽  
Barroon Ahmad Isma’eel ◽  
Sahabi Yusuf Ali
Keyword(s):  
Soil Fertility ◽  
Crop Yield ◽  
Clustering Algorithm ◽  
Soil Samples ◽  
North West ◽  
R Programming ◽  
Available Information ◽  
Northwest Region ◽  
The Relationship

Soil fertility determines a plant's development process that guarantees food sufficiency and the security of lives and properties through bumper harvests. The fertility of soil varies according to regions, thereby determining the type of crops to be planted. However, there is no repository or any source of information about the fertility of the soil in any region in Nigeria especially the Northwest of the country. The only available information is soil samples with their attributes which gives little or no information to the average farmer. This has affected crop yield in all the regions, more particularly the Northwest region, thus resulting in lower food production.  Therefore, this study is aimed at classifying soil data based on their fertility in the Northwest region of Nigeria using R programming. Data were obtained from the department of soil science from Ahmadu Bello University, Zaria. The data contain 400 soil samples containing 13 attributes. The relationship between soil attributes was observed based on the data. K-means clustering algorithm was employed in analyzing soil fertility clusters. Four clusters were identified with cluster 1 having the highest fertility, followed by 2 and the fertility decreases with an increasing number of clusters. The identification of the most fertile clusters will guide farmers on where best to concentrate on when planting their crops in order to improve productivity and crop yield.

DONG SON BRONZE DRUM - THE WORK OF THE LAC VIET PEOPLE

2018 ◽  
Author(s):  
Nguyen Van Hao
Keyword(s):  
Classification Criteria ◽  
Way Of Life ◽  
Tribal Identity ◽  
The Relationship

Bronze drums are widely distributed, broader than the range of a nation. Therefore, the identification of each kind of drum is a basic subject, should be concerned. In determining the tribal identity of the drum, the classification of drum is the key stage, the relationship between the objective of the classification and classification criteria is the relation as shape and shadow, if there is no right criteria then the result of division will be difficult to reach the desired goal. Likewise, the criterion of the pattern on the bronze drum brought to the affirmation is the Dong Son bronze drum of the Lac Viet people. And the parallel is the affirmation of the culture, way of life, residence of the nation created the drum.

scholarly journals Pituitary MRI characteristics in 297 acromegaly patients based on T2-weighted sequences

2015 ◽  
Vol 22 (2) ◽  
pp. 169-177 ◽  
Author(s):  
Iulia Potorac ◽  
Patrick Petrossians ◽  
Adrian F Daly ◽  
Franck Schillo ◽  
Claude Ben Slama ◽  
...  
Keyword(s):  
Large Population ◽  
Optic Chiasm ◽  
Research Priority ◽  
Maximal Diameter ◽  
Magnetic Resonance Imaging Mri ◽  
Multimodal Management ◽  
Mri Characteristics ◽  
Weighted Sequences ◽  
The Relationship

Responses of GH-secreting adenomas to multimodal management of acromegaly vary widely between patients. Understanding the behavioral patterns of GH-secreting adenomas by identifying factors predictive of their evolution is a research priority. The aim of this study was to clarify the relationship between the T2-weighted adenoma signal on diagnostic magnetic resonance imaging (MRI) in acromegaly and clinical and biological features at diagnosis. An international, multicenter, retrospective analysis was performed using a large population of 297 acromegalic patients recently diagnosed with available diagnostic MRI evaluations. The study was conducted at ten endocrine tertiary referral centers. Clinical and biochemical characteristics, and MRI signal findings were evaluated. T2-hypointense adenomas represented 52.9% of the series, were smaller than their T2-hyperintense and isointense counterparts (P<0.0001), were associated with higher IGF1 levels (P=0.0001), invaded the cavernous sinus less frequently (P=0.0002), and rarely caused optic chiasm compression (P<0.0001). Acromegalic men tended to be younger at diagnosis than women (P=0.067) and presented higher IGF1 values (P=0.01). Although in total, adenomas had a predominantly inferior extension in 45.8% of cases, in men this was more frequent (P<0.0001), whereas in women optic chiasm compression of macroadenomas occurred more often (P=0.0067). Most adenomas (45.1%) measured between 11 and 20 mm in maximal diameter and bigger adenomas were diagnosed at younger ages (P=0.0001). The T2-weighted signal differentiates GH-secreting adenomas into subgroups with particular behaviors. This raises the question of whether the T2-weighted signal could represent a factor in the classification of acromegalic patients in future studies.

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