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Chromosomal Variation in Two Species of Hordeum  [PDF]
Mst. Nahida Laiju,G. Kabir,M.J. Islam,, M. Hasanuzzaman
Asian Journal of Plant Sciences , 2003,
Abstract: The present study was conducted for karyomorphological investigation in 15 lines of two species of Hordeum. All the lines showed a diploid chromosome number of 14. Differences were observed regarding chromosome length, total chromatin length (TCL), type etc. among the 15 entries. The longest (11.06 m) chromosomes were observed in BTON-10 while the shortest (4.23 m) in BEL-4 and BEL-36 of Hordeum vulgare. Extra large chromosomes were found in BEL-4 (1 pair) and BTON-10 (5 pairs) of H. vulgare. Large type chromosomes were found in BHV-105, BTON-10 and conquest of H. vulgare. Medium type and relatively short type chromosomes were absent in BEL-36, BHV-1 and BTON-10 of H. vulgare, respectively. More metacentric chromosomes (7 pairs) were found in BHV-1 of H. vulgare. Maximum chromatin length (70.21 m) was also found in BTON-10 and minimum (40.96 m) in BEL-36 of H. vulgare. Maximum (47.76%) and minimum (39.88%) total fractional percentage (TF %) were found in BHV-1 and API-19 of H. vulgare, respectively. Each line has a specific chromosomal morphology which might be responsible for the variations of Hordeum species.
Untangling Nucleotide Diversity and Evolution of the H Genome in Polyploid Hordeum and Elymus Species Based on the Single Copy of Nuclear Gene DMC1  [PDF]
Dongfa Sun, Genlou Sun
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0050369
Abstract: Numerous hybrid and polypoid species are found within the Triticeae. It has been suggested that the H subgenome of allopolyploid Elymus (wheatgrass) species originated from diploid Hordeum (barley) species, but the role of hybridization between polyploid Elymus and Hordeum has not been studied. It is not clear whether gene flow across polyploid Hordeum and Elymus species has occurred following polyploid speciation. Answering these questions will provide new insights into the formation of these polyploid species, and the potential role of gene flow among polyploid species during polyploid evolution. In order to address these questions, disrupted meiotic cDNA1 (DMC1) data from the allopolyploid StH Elymus are analyzed together with diploid and polyploid Hordeum species. Phylogenetic analysis revealed that the H copies of DMC1 sequence in some Elymus are very close to the H copies of DMC1 sequence in some polyploid Hordeum species, indicating either that the H genome in theses Elymus and polyploid Hordeum species originated from same diploid donor or that gene flow has occurred among them. Our analysis also suggested that the H genomes in Elymus species originated from limited gene pool, while H genomes in Hordeum polyploids have originated from broad gene pools. Nucleotide diversity (π) of the DMC1 sequences on H genome from polyploid species (π = 0.02083 in Elymus, π = 0.01680 in polyploid Hordeum) is higher than that in diploid Hordeum (π = 0.01488). The estimates of Tajima's D were significantly departure from the equilibrium neutral model at this locus in diploid Hordeum species (P<0.05), suggesting an excess of rare variants in diploid species which may not contribute to the origination of polyploids. Nucleotide diversity (π) of the DMC1 sequences in Elymus polyploid species (π = 0.02083) is higher than that in polyploid Hordeum (π = 0.01680), suggesting that the degree of relationships between two parents of a polyploid might be a factor affecting nucleotide diversity in allopolyploids.
Distinct Origin of the Y and St Genome in Elymus Species: Evidence from the Analysis of a Large Sample of St Genome Species Using Two Nuclear Genes  [PDF]
Chi Yan, Genlou Sun, Dongfa Sun
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0026853
Abstract: Background Previous cytological and single copy nuclear genes data suggested the St and Y genome in the StY-genomic Elymus species originated from different donors: the St from a diploid species in Pseudoroegneria and the Y from an unknown diploid species, which are now extinct or undiscovered. However, ITS data suggested that the Y and St genome shared the same progenitor although rather few St genome species were studied. In a recent analysis of many samples of St genome species Pseudoroegneria spicata (Pursh) à. L?ve suggested that one accession of P. spicata species was the most likely donor of the Y genome. The present study tested whether intraspecific variation during sampling could affect the outcome of analyses to determining the origin of Y genome in allotetraploid StY species. We also explored the evolutionary dynamics of these species. Methodology/Principal Findings Two single copy nuclear genes, the second largest subunit of RNA polymerase II (RPB2) and the translation elongation factor G (EF-G) sequences from 58 accessions of Pseudoroegneria and Elymus species, together with those from Hordeum (H), Agropyron (P), Australopyrum (W), Lophopyrum (Ee), Thinopyrum (Ea), Thinopyrum (Eb), and Dasypyrum (V) were analyzed using maximum parsimony, maximum likelihood and Bayesian methods. Sequence comparisons among all these genomes revealed that the St and Y genomes are relatively dissimilar. Extensive sequence variations have been detected not only between the sequences from St and Y genome, but also among the sequences from diploid St genome species. Phylogenetic analyses separated the Y sequences from the St sequences. Conclusions/Significance Our results confirmed that St and Y genome in Elymus species have originated from different donors, and demonstrated that intraspecific variation does not affect the identification of genome origin in polyploids. Moreover, sequence data showed evidence to support the suggestion of the genome convergent evolution in allopolyploid StY genome species.
Phylogenetic Relationships Between Mediterranean and Middle-asian Wild Species of the Genus Hordeum L. As Revealed by Biochemical and Molecular Markers
H. El Rabey,K.F. Abdellatif,M.K.H. Ebrahim,N. Abbas
Pakistan Journal of Biological Sciences , 2013,
Abstract: The phylogenetic relationships of 60 accessions of the genus Hordeum (29 Mediterranean and 20 middle-Asian wild accessions, together with nine American accessions and two of unknown origin), representing together nine species, were investigated by AFLP markers. Three hundred sixty six AFLP fragments were used for studying the molecular genetic diversity among the studied species, 339 out of them were polymorphic. Forty seven protein bands were obtained from the water soluble and the water insoluble seed storage protein by SDS-PAGE electrophoresis of 18 accessions representing nine species (two accessions/species). One band was common to all species and the other 46 bands were polymorphic. The phylogenetic tree deduced from AFLP analysis is concordant to a large extent with that deduced from seed storage protein. Highly significant cophenetic correlation coefficient was obtained between both AFLP (0.96) and seed storage protein (0.89) indicating the reliability of the results. The studied taxa were clustered according to their genome type. All Mediterranean and middle-Asian wild accessions could be integrated into the existing phylogenetic scheme.
Genetic analysis of morphological and physical stem characteristics determining lodging resistance in two- and six-rowed barley (Hordeum vulgare L.) lines
S. Je?…??owski,M. Surma,T. Adamski,P. Krajewski
International Agrophysics , 2005,
Abstract: The study presents the results of genetic analysis of selected morphological and physical stem characteristics determining lodging resistance in doubled haploid (DH) lines of spring barley produced from F1 hybrids of the six-rowed variety Klimek with the two-rowed variety Maresi. The DH lines, the initial forms, and F1 and F2 hybrids were tested in three-year field trials. Stem length, outside diameter and the thickness of stem walls were analyzed. Lodging rate was observed and stem material elasticity was examined using the ultrasound method. Analysis of variance was conducted for the obtained data and 6-rowed lines were compared with 2-rowed lines in terms of the investigated characteristics. Moreover, on the basis of DH lines and F1 and F2 hybrids, genetic parameters determining additive gene effects [d], dominance effects [h] and the effects of non-allelic interaction of loci in the homozygous [i] and heterozygous state [l] were estimated. For the investigated characteristics significant values of parameter [d] were found. Dominance effects turned out to be significant for stem length, stem tissue elasticity and lodging rate. Non-allelic interaction of homo- and heterozygous loci was significant for stem tissue elasticity and lodging rate. A comparison of 6-rowed and 2-rowed lines in terms of the investigated characteristics showed that 6-rowed forms exhibited smaller length and lower elasticity of stems, thinner stem walls and higher lodging rate than 2-rowed lines. It was also found that environmental factors (years) had an effect on both the mean values of the analyzed characteristics and on the difference between the 2- and 6-rowed barley lines.
Karyotypic Study of Seven Species of Hordeum in Fars Province  [cached]
A. R. Nasirzadeh,F. Ansari-Asl
Journal of Science and Technology of Agriculture and Natural Resources , 2007,
Abstract: A karyotypic study was performed on seven species of Hordeum Genus including, H. vulgare, H. spontaneum, H. glaucum, H. distichon, H. geniculatum , H. bulbosum and H. violaceum. According to the cytological studies in the laboratory, chromosome numbers and ploidy levels of species were identified. Chromosome analysese including the length of each chromosome, long and short arms length and long - short arm ratio were also done. For each species, the karyotype as an ideogram was drawn. The results showed that H. geniculatum, H. bulbosum, and H. violaceum were tetraploid (2n=4x=28) and the other species were diploid (2n=2x=14). Chromosomal study of H. geniculatum and H. distichon is reported for the first time from Iran. Karyotypic formula showed that the diploid species were 7m and tetraploid were 12m +2sm. According to the karyotypic symmetry, all species were in the 1A class. Using the S%, TF%, D.R.L., T.V. and X parameters, karyotypic symmetry of species was analyzed and determined.
Phylogenetic analysis of Hystrix and its related genera (Poaceae:Triticeae) based on the sequences of the gene encoding 3-phosphoglycerate kinase

遗传 , 2009,
Abstract: To estimate the phylogenetic relationships between Hystrix and its related genera (Poaceae: Triticeae), the sequences of the single-copy nuclear gene Pgk1 were analyzed for five Hystrix taxa, together with three Pseudoroegneria (St) species, two Hordeum (H) species, two Psathyrostachys (Ns) species, four Elymus (StH) species, five Leymus (NsXm) species, Thinopyrum bessarabicum (Eb), and Lophopyrum elongatum (Ee). Sequence analysis indicated that an 81bp Stowaway insertion occurred in the Pgk1 sequences of L. arenarius and Psa. juncea, and a 29 bp Copia insertion occurred in the Pgk1 sequences of Hy. duthiei, Hy. duthiei ssp. longearistata and L. akmolinensis. Phylogenetic analysis indicated that: (1) Hy. patula was closely related to Pseudoroegneria, Hordeum, and Elymus; (2) Hy. duthiei, Hy. duthiei ssp. longearistata, Hy. coreana, and Hy. komarovii were closely related to Psathyrostachys and Leymus. Based on these results, it is reasonable to transfer Hy. patula from Hystrix to Elymus, and to combine Hy. duthiei, Hy. duthiei ssp. longearistata, Hy. coreana, and Hy. komarovii into Leymus.
Stochastic Analysis Of A Two Species Model With Commensalism  [PDF]
International Journal of Innovative Research in Science, Engineering and Technology , 2013,
Abstract: This paper deals with an exploration on mathematical model of commensal and host species, in the presence of randomly fluctuating driving forces on the growth of the species at time ‘ ’ of a conventional eco system. The model consists of a commensal ( ), a host ( ) that benefit without getting effected either positively or adversely. The model is described by a pair of non-linear differential equations. Stochastic stability, in terms of the variances of the populations of the given system is derived using technique of Fourier transform.
A nonlinear two-species oscillatory system: bifurcation and stability analysis
Malay Bandyopadhyay,Rakhi Bhattacharya,C. G. Chakrabarti
International Journal of Mathematics and Mathematical Sciences , 2003, DOI: 10.1155/s0161171203201174
Abstract: The present paper dealing with the nonlinear bifurcation analysis of two-species oscillatory system consists of three parts. The first part deals with Hopf-bifurcation and limit cycle analysis of the homogeneous system. The second consists of travelling wave train solution and its linear stability analysis of the system in presence of diffusion. The last deals with an oscillatory chemical system as an illustrative example.
Mean-field analysis of two-species TASEP with attachment and detachment  [PDF]
Minghua Song,Yunxin Zhang
Quantitative Biology , 2015,
Abstract: In cells, most of cargos are transported by motor proteins along microtubule. Biophysically, unidirectional motion of large number of motor proteins along a single track can be described by totally asymmetric simple exclusion process (TASEP). From which many meaningful properties, such as the appearance of domain wall (defined as the borderline of high density and low density of motor protein along motion track) and boundary layers, can be obtained. However, it is biologically obvious that a single track may be occupied by different motor species. So previous studies based on TASEP of one particle species are not reasonable enough to find more detailed properties of the motion of motors along a single track. To address this problem, TASEP with two particle species is discussed in this study. Theoretical methods to get densities of each particle species are provided. Using these methods, phase transition related properties of particle densities are obtained. Our analysis show that domain wall and boundary layer of single species densities always appear simultaneously with those of the total particle density. The height of domain wall of total particle density is equal to the summation of those of single species. Phase diagrams for typical model parameters are also presented. The methods presented in this study can be generalized to analyze TASEP with more particle species.
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