bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular characterization and expression analysis of a highly conserved ricemago nashi1homolog
Authors: Swidzinski Jodi A , Zaplachinski Steven T , Chuong Simon DX , Wong Josée FK , Muench Douglas G
Published: April 2011

Mago Nashi, a protein initially shown to be essential in the development of the Drosophila oocyte, is highly conserved among species and shows no homology to any other known cellular proteins. Here we report the nucleotide sequence of a cDNA and a partial gene that encode rice Mago Nashi protein homologs. In addition, we present the tissue-specific expression pattern of mago nashi at the level of RNA and protein. The rice Mago Nashi protein shares at least 73% amino acid identity with all known animal homologs. Genomic DNA gel blot analysis indicates that two copies of the mago nashi gene exist in the rice genome, one of which has identical intron positions to those found in an Arabidopsis homolog. mago nashi is expressed in root, leaf and developing seed tissue as determined by RNA and protein gel blot analysis. Evidence from Drosophila, Caenorhabditis elegans and human studies of Mago Nashi suggests that a major function of this protein is its involvement in RNA localization. The highly conserved amino acid sequence of all Mago Nashi protein homologs across kingdoms suggests that the plant version of this protein may similarly be involved in RNA localization.Key words: development, gene conservation, RNA localization.
The synaptic behaviour of the wild forms ofTriticum turgidumandT. timopheevii
Authors: Martínez M , Naranjo T , Cuadrado C , Romero C
Published: April 2011

Different wild allopolyploid species of Triticeae show extensive bivalent formation at zygotene while a considerable number of multivalents is present in cultivated polyploid wheats. To study the chromosome behaviour at early meiotic stages in wild forms of tetraploid wheats Triticum turgidum and T. timopheevii (2n = 4x = 28) we have analysed the synaptic pattern in fully traced spread nuclei at mid- and late zygotene and at pachytene of wild accessions of these species. The mean number of synaptonemal complex (SC) bivalents at mid-zygotene ranged from 12.22 to 13.14 among the accessions studied indicating a strong restriction of synapsis initiation to homologous chromosomes. The mean of bivalents increased at pachytene because of the transformation of multivalents into bivalents. Ring bivalents observed at metaphase I support that SC bivalents were formed by homologous chromosomes. The average values of SC bivalents at mid-zygotene in the wild forms are much higher than the average values observed in the cultivated tetraploid wheats but similar to that of a mutant line of T. turgidum with a duplication that includes Ph1, the major homoeologous pairing suppressor locus. These results suggest that the efficiency of the mechanism operating in the homologous recognition for synapsis is higher in wild wheat populations than in cultivated varieties. Apparently, a relatively detrimental modification of the pairing regulating genetic system accompanied the domestication of the wild wheat forms.Key words: Ph1 locus, Triticum turgidum, Triticum timopheevii, synaptonemal complex, diploidisation.
Genomic in situ hybridization (GISH) discriminates between the A and the B genomes in diploid and tetraploid Setaria species
Authors: Benabdelmouna A , Shi Y , Abirached-Darmency M , Darmency H
Published: April 2011

Genomic in situ hybridization (GISH) was used to investigate genomic relationships between different Setaria species of the foxtail millet gene pool (S. italica) and one interspecific F1 hybrid. The GISH patterns obtained on the two diploid species S. viridis (genome A) and S. adhaerans (genome B), and on their F1 hybrid showed clear differentiation between these two genomes except at the nucleolar organizing regions. Similar GISH patterns allowed differentiation of S. italica from S. adhaerans. However, GISH patterns did not distinguish between the genomes of S. italica and its putative wild ancestor S. viridis. GISH was also applied to polyploid Setaria species and enabled confirmation of the assumed allotetraploid nature of S. faberii and demonstration that both S. verticillata and S. verticillata var. ambigua were also allotetraploids. All these tetraploid species contained two sets of 18 chromosomes each, one from genome A and the other from genome B. Only one polyploid species, S. pumila, was shown to bear an unknown genomic composition that is not closely related either to genome A or to genome B.Key words: Setaria, genomic in situ hybridization, genome analysis.
Microsatellite markers reveal chimeric origin of redesignated chromosome 4A of wheat fromTriticum urartuand other species
Authors: Vasu Kuraparthy , Aghaee-Sarbarzel M S , Dhaliwal H S
Published: April 2011

Although a new nomenclature has been adopted for wheat in which chromosome 4A (4AO) has been renamed 4B (4BN) and chromosome 4B (4BO) has been renamed 4A (4AN), their specific origin remains uncertain. The use of wheat microsatellite (WMS) markers mapped to chromosomes 4ANand 4BNin a set of polyploid wheats and diploid genome donors has unequivocally indicated that the entire short arm of 4AN, some part of 4ANL, and a segment of 4BNL were derived from Triticum urartu. The presence of a T. urartu-specific allele at locus gwm368 on 4BNL and of an Aegilops speltoides allele at locus gwm397 on 4ANL suggests the possibility of a reciprocal translocation between 4ANL and 4BNL. The subcentromeric and telomeric regions of 4ANL corresponding to heterochromatic C-bands were derived neither from diploid wheats nor from Ae. speltoides or Aegilops longissima.Key words: microsatellite markers, chromosome 4A, Triticum urartu, wheat, Aegilops speltoides.
Specific genetic markers for wheat, spelt, and four wild relatives: comparison of isozymes, RAPDs, and wheat microsatellites
Authors: Guadagnuolo Roberto , Bianchi Dessislava Savova , Felber François
Published: April 2011

Three types of markersisozymes, RAPDs (random amplified polymorphic DNAs), and wheat microsatelliteswere tested on wheat, spelt, and four wild wheat relatives (Aegilops cylindrica, Elymus caninus, Hordeum marinum, and Agropyron junceum). The aim was to evaluate their capability to provide specific markers for differentiation of the cultivated and wild species. The markers were set up for subsequent detection of hybrids and introgression of wheat DNA into wild relatives. All markers allowed differentiation of the cultivated from the wild species. Wheat microsatellites were not amplified in all the wild relatives, whereas RAPDs and isozymes exhibited polymorphism for all species. The dendrograms obtained with RAPD and isozyme data separated Swiss wheat cultivars from those collected in Austria and England, while no difference was found between Swiss spelt and wheat. RAPD data provided a weak discrimination between English and Austrian E. caninus. The microsatellite-based dendrogram discriminated populations of Ae. cylindrica, but no clear separation of H. marinum from E. caninus was revealed. The similarity matrices based on the three different sets of data were strongly correlated. The highest value was recorded between the matrices based on RAPDs and isozymes (Mantel's test, r = 0.93). Correlations between the similarity matrix based on microsatellites and matrices based on RAPDs and isozymes were lower: 0.74 and 0.68, respectively. While microsatellites are very useful for comparisons of closely related accessions, they are less suitable for studies involving less-related taxa. Isozymes provide interesting markers for species differentiation, but their use seems less appropriate for studies of within-species genetic variation. RAPDs can produce a large set of markers, which can be used for the evaluation of both between- and within-species genetic variation, more rapidly and easily than isozymes and microsatellites.Key words: Triticeae, isozymes, RAPDs, microsatellites, polymorphism.
Characterization of AFLP markers in damselflies: prevalence of codominant markers and implications for population genetic applications
Authors: Wong A , Forbes M R , Smith M L
Published: April 2011

Amplified fragment length polymorphism (AFLP) analysis is becoming increasingly popular as a method for generating molecular markers for population genetic applications. For practical considerations, it is generally assumed in population studies that AFLPs segregate as dominant markers, i.e., that present and absent are the only possible states of a given locus. We tested the assumption of dominance in natural populations of the damselfly Nehalennia irene (Hagen) (Odonata: Coenagrionidae). Electro-blotted AFLP products from 21 samples were probed with individual markers. Eleven markers were analyzed, of which two were monomorphic and nine were polymorphic. Only two of the polymorphic markers behaved in a strictly dominant manner. The remaining seven polymorphic markers displayed various degrees of codominance, with 210 visible alleles in the sample. Of the three markers displaying the highest degree of variability, two contained microsatellite repeat tracts. Our results suggest that the assumption of dominance is unfounded. As a result, AFLP analysis may be unsuitable for estimating several important population genetic parameters, including genetic diversity.Key words: AFLP, population genetics, dominant markers, microsatellite, insect, damselfly.
The biological basis of epistasis between quantitative trait loci for flavone and 3-deoxyanthocyanin synthesis in maize (Zea maysL.)
Authors: McMullen Michael D , Snook Maurice , Lee Elizabeth A , Byrne Patrick F , Kross Heike , Musket Theresa A , Houchins Katherine , Coe, Jr. Edward H
Published: April 2011

A major weakness in our understanding of the genetic basis of complex traits has been that of defining the extent and biological basis of epistasis. Our research group has been studying the genetic control of the accumulation of maysin, a C-glycosyl flavone, in maize, Zea mays (L.), silks. Previously, we demonstrated the importance of the p1 locus as a QTL for maysin synthesis. The p1 locus often exhibits significant epistatic interactions with other loci. We developed a mapping population, (W23a1 × GT119)F2, specifically designed to test whether genes in an intersecting pathway might be detected as QTLs for maysin synthesis and result in epistatic interaction effects. The a1 gene is not required for the synthesis of flavones but is required for the synthesis of 3-deoxyanthocyanins, an intersecting pathway, in maize silks. The p1 locus (P < 0.0001) was a QTL for both flavones and 3-deoxyanthocyanins. The a1 locus was also highly significant (P < 0.0001) for both traits, as was the p1 × a1 epistatic interaction (P < 0.0001). Our results demonstrate that altering the flux of biochemical intermediates between pathways may be the biological basis of major QTL effects and epistatic interactions.Key words: maysin, epistasis, QTL, insect resistance.
A two-locus model for experience-conditioned direction of paw usage in the mouse is suggested by dominant and recessive constitutive paw usage behaviours
Authors: Biddle Fred G , Jones Danielle A , Eales Brenda A
Published: April 2011

Left-right direction of paw usage in the mouse depends on the genotype and the directional nature of the test. There are two phenotypic classes; in some strains, direction of paw usage is learned or conditioned by the direction of the initial test chamber and the experience of reaching and, in other strains, paw usage is a constitutive behaviour not affected by previous experience. We report the evidence for locus heterogeneity in the cause of constitutive versus experience-conditioned paw usage from a phenotypic analysis of F1 hybrid generations from the experience-conditioned C57BL/6J, C3H/HeHa, and SWV strains and the constitutive CDS/Lay and DBA/2J strains. The F1 hybrids between strains of different phenotypic classes provide evidence of locus heterogeneity. Constitutive paw usage in CDS/Lay is phenotypically dominant to experience-conditioned behaviour in both C57BL/6J and SWV. However, constitutive paw usage in DBA/2J is phenotypically recessive to experience-conditioned behaviour in C57BL/6J and dominant to experience-conditioned behaviour in SWV. Among the experience-conditioned strains, C57BL/6J is highly lateralized but SWV is only weakly lateralized. Our data suggest a model in which C57BL/6J may have a "strong" allele that identifies a functional difference between the constitutive paw usage of CDS/Lay and DBA/2J. DBA/2J may have a loss-of-function mutation at the same locus that is recessive to the strong C57BL/6J allele. SWV may have a "weak" allele and the (SWV × D2)F1 compound heterozygote may be below a threshold for detectability of experience-conditioned behaviour, making the constitutive behaviour of DBA/2J appear to be dominant to the experience-conditioned behaviour of SWV. CDS/Lay may have a dominant allele at a second locus that suppresses experience-conditioned behaviour in all F1 hybrids.Key words: mouse, left-right asymmetry of hand usage, behavioural genetics, experience-conditioned behaviour, dominant and recessive constitutive behaviour, learning, memory.
Construction of a reference linkage map for melon
Authors: Oliver M , Garcia-Mas J , Cardús M , Pueyo N , López-Sesé A I , Arroyo M , Gómez-Paniagua H , Arús P , Vicente M C de
Published: April 2011

A map of melon (Cucumis melo L.) with 411 markers (234 RFLPs, 94 AFLPs, 47 RAPDs, 29 SSRs, five inter-SSRs, and two isozymes) and one morphological trait (carpel number) was constructed using the F2progeny of a cross between the Korean accession PI161375 and the Spanish melon type 'Pinyonet Piel de Sapo'. RFLPs were obtained using 212 probes from different genomic and cDNA melon libraries, including 16 Arabidopsis ESTs, 13 Cucumis known genes, and three resistant gene homologues. Most loci (391) mapped to 12 major linkage groups, spanning a total genetic distance of 1197 cM, with an average map interval of 3 cM/marker. The remaining 21 loci (six RAPDs and 15 AFLPs) were not linked. A majority (66%) of the markers were codominant (RFLPs, SSRs, and isozymes), making them easily transferable to other melon crosses. Such markers can be used as a reference, to merge other melon and cucumber maps already constructed. Indeed, some of them (23 SSRs, 14 RFLPs, one isozyme, and one morphological trait) could act as anchor points with other published cucurbit maps.Key words: Cucumis melo, genetic map, molecular markers, RFLPs, SSRs.
Multiple flowering time QTLs within severalBrassicaspecies could be the result of duplicated copies of one ancestral gene
Authors: Axelsson Tomas , Shavorskaya Oksana , Lagercrantz Ulf
Published: April 2011

Quantitative trait locus (QTL) analysis was used to study the evolution of genes controlling the timing of flowering in four Brassica genomes that are all extensively replicated. Comparative mapping showed that a chromosomal region from the top of Arabidopsis thaliana chromosome 5 corresponded to three homoeologous copies in each of the diploid species Brassica nigra, B. oleracea, and B. rapa and six copies in the amphidiploid B. juncea. QTLs were detected in two of the three replicated segments in each diploid genome and in three of the six replicated segments in B. juncea. These results indicate that, for the studied trait, multiple QTLs resulting from genome duplication is the rule rather than the exception. Brassica homologues to two candidate genes (CO and FLC) identified from the corresponding A. thaliana region were mapped. CO homologues mapped close to the QTL peaks in eight of nine QTLs, while FLC homologues mapped farther away in those cases where the mapping resolution allowed a comparison. Thus, our data are consistent with the hypothesis that all the major QTLs we detected in the different species of Brassica could be the result of duplicated copies of the same ancestral gene, possibly the ancestor of CO.Key words: Brassica, Arabidopsis, comparative mapping, genome duplication, flowering time.
Construction of a linkage map of the Rennell Island Tall coconut type (Cocos nuciferaL.) and QTL analysis for yield characters
Authors: Lebrun P , Baudouin L , Bourdeix R , Konan J Louis , Barker J HA , Aldam C , Herrán A , Ritter E
Published: April 2011

AFLP and SSR DNA markers were used to construct a linkage map in the coconut (Cocos nucifera L.; 2n = 32) type Rennell Island Tall (RIT). A total of 227 markers were arranged into 16 linkage groups. The total genome length corresponded to 1971 cM for the RIT map, with 523 markers per linkage group. QTL analysis for yield characters in two consecutive sampling periods identified nine loci. Three and two QTLs were detected for number of bunches and one and three QTLs for number of nuts. The correlation of trait values between characters and evaluation periods is partially reflected in identical QTLs. The QTLs represent characters that are important in coconut breeding. The cosegregation of markers with these QTLs provides an opportunity for marker-assisted selection in coconut breeding programmes.Key words: coconut, QTL, AFLP, SSR, marker-assisted selection (MAS).
Influence of genetic background and heterozygosity on meiotic recombination inArabidopsis thaliana
Authors: Barth Susanne , Melchinger Albrecht E , Devezi-Savula Beate , Lübberstedt Thomas
Published: April 2011

Plant breeding relies on genetic variability generated by meiotic recombination. Control of recombination frequencies is not yet possible, but would significantly extend the options for plant-breeding strategies. A prerequisite would be variability of recombination frequencies. In this study, 15 transgenic kanamycin (KR) and hygromycin (HR) resistance gene insertions mapping to the five Arabidopsis thaliana chromosomes were used as genetic markers. Recombination frequencies were determined from the frequencies of resistance phenotypes within populations segregating for linked KRand HRmarkers. Recombination frequencies of marker pairs were compared among these four ecotypes, among F1s in both reciprocal forms derived from these ecotypes, and between F1s and their parent lines. On average, the recombination frequencies in F1crosses were substantially higher (up to 2-fold) than in the homozygous parental ecotypes. A strong negative correlation between genetic similarities of ecotypes and recombination frequencies was detected for two adjacent marker pairs located on the long arm of chromosome 3, but not for marker pairs in other genomic regions. Our results suggest that heterozygosity influences recombination in plant breeding, and cannot be ignored in genetic mapping of genomes.Key Words: meiotic recombination, Arabidopsis, genetic background, heterozygosity, homozygosity.
Evidence that the N-terminal extension of the Vicieae convicilin genes evolved by intragenic duplications and trinucleotide expansions
Authors: Sáenz de Miera L E , Pérez de la Vega M
Published: April 2011

This study was aimed to identify lentil (Lens culinaris subsp. culinaris) convicilin genes and to carry out a comparative analysis of these genes in the tribe Vicieae. Convicilins differ from vicilins, a related group of plant seed storage proteins, mainly by the presence of an additional sequence of amino acids in the sequence corresponding to the first exon, referred as the N-terminal extension. A single gene for convicilin, a component of legume seed storage proteins, was identified in the cultivated lentil. In this species, the N-terminal extension is formed by a stretch of 126 amino acids of which 59.2% are charged amino acids: 29.6% glutamic acid, 3.2% aspartic acid, 14.4% arginine, 8.8% lysine, and 3.2% histidine. This lentil convicilin sequence is similar to the sequence of convicilins in other species of the tribe Vicieae. However, the size of the N-terminal extension clearly differs among convicilins. Sequence comparison and phylogenetic analyses including convicilin and vicilin of Vicieae species indicated that the differentiation between vicilins and convicilins predated the differentiation of the two vicilin gene families (47- and 50-kDa vicilins), and that the N-terminal extension evolved mainly by a series of duplications of short internal sequences and triplet expansions, the predominant one being GAA.Key words: convicilin, evolution by duplications, Lens culinaris Medik., lentil, legumes, trinucleotide expansion.
Polymorphism of PCR-based markers targeting exons, introns, promoter regions, and SSRs in maize and introns and repeat sequences in oat
Authors: Holland J B , Helland S J , Sharopova N , Rhyne D C
Published: April 2011

Sequence databases could be efficiently exploited for development of DNA markers if it were known which gene regions reveal the most polymorphism when amplified by PCR. We developed PCR primer pairs that target specific regions of previously sequenced genes from Avena and Zea species. Primers were targeted to amplify 40 introns, 24 exons, and 23 promoter regions within 54 maize genes. We surveyed 48 maize inbred lines (previously assayed for simple-sequence repeat (SSR) polymorphism) for amplification-product polymorphism. We also developed primers to target 14 SSRs and 12 introns within 18 Avena genes, and surveyed 22 hexaploid oat cultivars and 2 diploid Avena species for amplification-product polymorphism. In maize, 67% of promoter markers, 58% of intron markers, and 13% of exon markers exhibited amplification-product polymorphisms. Among polymorphic primer pairs in maize, genotype diversity was highest for SSR markers (0.60) followed by intron markers (0.46), exon markers (0.42), and promoter markers (0.28). Among all Avena genotypes, 64% of SSR markers and 58% of intron markers revealed polymorphisms, but among the cultivars only, 21% of SSR markers and 50% of intron markers were polymorphic. Polymorphic-sequence-tagged sites for plant-breeding applications can be created easily by targeting noncoding gene regions.Key words: Avena, Zea, genetic diversity, DNA sequence.
TAFII70 protein in Cajal bodies of the amphibian germinal vesicle
Authors: Bucci Stefania , Giani Letizia , Mancino Giorgio , Pellegrino Mario , Ragghianti Matilde
Published: April 2011

The localization of the TATA-binding protein (TBP) associated factor II70 (TAFII70) in the germinal vesicle (GV) of newt oocytes was investigated. In spreads of GV content, anti-hTAFII70 monoclonal antibody (mAb) stained Cajal bodies (CBs) that were either attached to specific sites on the lampbrush chromosomes or free in the nucleoplasm. To confirm this localization the PwTAFII70 cDNA was cloned and myc-tagged transcripts injected into the oocyte cytoplasm. Newly translated PwTAFII70 protein was detected a few hours later in the Cajal bodies. These data support the hypothesis that Cajal bodies are the assembly sites of the transcription machinery of the oocyte nucleus. TAFII70 protein can play a role in lampbrush transcription; alternatively TAFII70 can be considered a component in the subset of TFIID complexes that do not function during oogenesis, but are accumulated in the oocyte for later use during early development.Key words: TAFII70, Cajal body, lampbrush chromosomes, RNA transcription and processing, newts, Pleurodeles.
Abridged 5S rDNA units in sea beet (Beta vulgarissubsp.maritima)
Authors: Turner Daniel J , Brown Terence A
Published: April 2011

Amplification by polymerase chain reaction of the 5S rDNA repeat units of Beta vulgaris subsp. maritima resulted in a 350-bp product corresponding to the full-length 5S unit, but also revealed 4 abridged unit classes, each with a deletion that removed most of the spacer and 12–76 bp of the coding sequence. Each abridged type lacks at least 1 of the conserved elements involved in transcription of the 5S gene, and so appear to be nonfunctional. Network analysis revealed that the abridged units are evolving in the same manner as the full-length versions.Key words: 5S rDNA, Beta vulgaris subsp. maritima, network analysis, sea beet.
A cluster of diagnostic Hsp68 amino acid sites that are identified inDrosophilafrom themelanogasterspecies group are concentrated around β-sheet residues involved with substrate binding
Authors: Kellett Mark , McKechnie Stephen W
Published: April 2011

The coding region of the hsp68 gene has been amplified, cloned, and sequenced from 10 Drosophila species, 5 from the melanogaster subgroup and 5 from the montium subgroup. When the predicted amino acid sequences are compared with available Hsp70 sequences, patterns of conservation suggest that the C-terminal region should be subdivided according to predominant secondary structure. Conservation levels between Hsp68 and Hsp70 proteins were high in the N-terminal ATPase and adjacent β-sheet domains, medium in the α-helix domain, and low in the C-terminal mobile domain (78%, 72%, 41%, and 21% identity, respectively). A number of amino acid sites were found to be "diagnostic" for Hsp68 (28 of ~635 residues). A few of these occur in the ATPase domain (385 residues) but most (75%) are concentrated in the β-sheet and α-helix domains (34% of the protein) with none in the short mobile domain. Five of the diagnostic sites in the β-sheet domain are clustered around, but not coincident with, functional sites known to be involved in substrate binding. Nearly all of the Hsp70 family length variation occurs in the mobile domain. Within montium subgroup species, 2 nearly identical hsp68 PCR products that differed in length are either different alleles or products of an ancestral hsp68 duplication.Key words: Hsp70, Hsp68, diagnostic sites, Drosophila melanogaster, montium subgroup.
Unusual arrangement of thehsp68locus in thevirilisspecies group ofDrosophilaimplicates evolutionary loss of anhsp68gene
Authors: Velikodvorskaia Vera V , Lyozin Georgii T , Feder Martin E , Evgen'ev Michael B
Published: April 2011

Unlike all other Drosophila species studied to date, species in the virilis group of Drosophila have 2 complete copies of hsp68 arranged in inverted head-to-head orientation. Evidence for this conclusion includes Southern blots for D. virilis, D. lummei, and D. montana, PCR analysis of the former 2 species, in situ hybridization in D. virilis × D. lummei hybrids, and the complete nucleotide sequence of the locus in D. lummei. This organization resembles the primitive state of hsp70 in Diptera. Moreover, the Hsp68 peptide sequence for D. virilis and D. lummei is intermediate between that of Hsp70 and Hsp68 from other Drosophila spp. Therefore, we suggest that the hsp68 locus may have arisen via duplication of the hsp70 locus (or vice versa) early in the history of the genus Drosophila, with 1 hsp68 copy subsequently lost in most other Drosophila species groups.Key words: hsp68, Drosophila, Drosophila virilis, evolution, molecular chaperone, heat-shock protein, molecular evolution, gene duplication, gene loss.
Identification of a new class of recombinant prolamin genes in wheat
Authors: Nagy Ila J , Takács Imre , Juhász Angéla , Tamás László , Bedõ Zoltán
Published: April 2011

A novel storage protein gene with obvious wheat chimeric structure was isolated from an immature kernel-specific cDNA library prepared from the old Hungarian variety, Bánkúti 1201. This clone contains γ-gliadin sequences in the 5′ region and LMW-glutenin sequences on the 3′ end. A frameshift mutation was also introduced by the putative recombination event. Hence, the amino acid sequence of the C-terminal region was transformed to a completely new polypeptide. Based on this finding, 7 additional recombinant prolamin genes of similar structure were isolated with specific PCR primers. The 8 chimeric clones seem to be derived from 4 individual γ-gliadin and 3 LMW-glutenin sequences. These genes show remarkable diversity in size, gliadin:glutenin ratio, frameshift mutations, and sulphur content. The putative functional characteristics of the chimeric polypeptides and problems related to the origin of the encoding genes are discussed.Key words: prolamin, chimeric genes, recombination, wheat cDNA library.
Development and validation of molecular markers linked to anAegilops umbellulata–derived leaf-rust-resistance gene,Lr9, for marker-assisted selection in bread wheat
Authors: Gupta Sudhir Kumar , Charpe Ashwini , Koul Sunita , Prabhu Kumble Vinod , Haq Qazi Mohd. Rizwanul
Published: April 2011

An Aegilops umbellulata–derived leaf-rust-resistance gene, Lr9, was tagged with 3 random amplified polymorphic DNA (RAPD) markers, which mapped within 1.8 cM of gene Lr9 located on chromosome 6BL of wheat. The markers were identified in an F2population segregating for leaf-rust resistance, which was generated from a cross between 2 near-isogenic lines that differed in the alien gene Lr9 in a widely adopted agronomic background of cultivar 'HD 2329'. Disease phenotyping was done in controlled environmental conditions by inoculating the population with the most virulent pathotype, 121 R63-1 of Puccinia triticina. One RAPD marker, S5550, located at a distance of 0.8 ± 0.008 cM from the Lr9 locus, was converted to sequence-characterized amplified region (SCAR) marker SCS5550. The SCAR marker was validated for its specificity to gene Lr9 against 44 of the 50 known Lr genes and 10 wheat cultivars possessing the gene Lr9. Marker SCS5550was used with another SCAR marker, SCS73719, previously identified as being linked to gene Lr24 on a segregating F2population to select for genes Lr9 and Lr24, respectively, demonstrating the utility of the 2 markers in marker-assisted gene pyramiding for leaf-rust resistance in wheat.Key words: wheat, leaf rust resistance, Lr9, Lr24, RAPD, SCAR.
Intergenomic recombination in F1 lily hybrids (Lilium) and its significance for genetic variation in the BC1 progenies as revealed by GISH and FISH
Authors: Barba-Gonzalez R , Ramanna M S , Visser R G.F , Van Tuyl J M
Published: April 2011

Intergenomic recombination was assessed in a BC1 population of Oriental (O) × Asiatic (A) lilies (Lilium) backcrossed to Asiatic parents. This population consisted of 38 plants generated from the 2n gametes from 2 genotypes (951502-1 and 952400-1) of the diploid F1, Oriental × Asiatic lilies (2n = 2x = 24) as parents. In the majority of BC1 plants, there was evidence that first division restitution, with and without crossovers, resulted in functional gametes. However, there were 5 BC1 plants in which 2n gametes originated from indeterminate meiotic restitution (IMR). Based on the number of recombinant chromosomes for a particular homoeologous pair, 3 types of plants were identified: (i) those with both the reciprocal product of a crossover (O/A, A/O, where O represents the centromere of the O genome and A the recombinant segment of Asiatic chromosome, and vice versa); (ii) those with 1 normal chromosome of the O genome and a recombinant chromosome (O, A/O); and (iii) those with 1 normal chromosome of the A genome and a recombinant chromosome (A, O/A). An important feature of A × OA backcross progeny is the occurrence of substitutions for the segment distal in the crossover wherever the recombinant chromosome O/A was present. In the case of IMR, the substitution occurred for both proximal and distal recombinant segments. The significance of these substitutions is that they offer the potential for the phenotypic expression of recessive genes in polyploids (i.e., nulliplex genotype).Key words: genomic in situ hybridization (GISH), fluorescence in situ hybridization (FISH), unreduced gametes, allopolyploid.
Biological aspects of Amazonian fishes. IX. Cytogenetic studies in two species of the genus Semaprochilodus (Pisces, Prochilodontidae)
Authors: Feldberg Eliana , Bertollo Luiz Antonio Carlos , Toledo Lurdes Foresti de Almeida , Foresti Fausto , Filho Orlando Moreira , Santos Altair Fernandes dos
Published: April 2011

The karyotype of Semaprochilodus insignis and Semaprochilodus taeniurus were analyzed through the conventional Giemsa staining, C-banding, and the nucleolar organizer regions. The diploid number is the same (2n = 54) in both species, but S. taeniurus shows a chromosomic system of the ZZ/ZW type. This and some other differences between the two karyotypes will be useful in further studies on the possible hybrid origin of the "jaraqui açú," a low frequency form that is observed together with S. insignis and S. taeniurus.

Key words: fish, ZZ/ZW system, constitutive heterochromatin, nucleolar organizing regions.
Cytogenetic analysis of mitotic and salivary gland chromosomes in the Medfly Ceratitis capitata
Authors: Zacharopoulou A.
Published: April 2011

The present investigation constitutes a first attempt to study the salivary gland chromosomes of Ceratitis capitata. A photographic representation of the polytene chromosomes from the salivary gland of this species is provided and the tips, as well as some important landmarks, are recognized in each arm. There is an XX/XY pair and five pairs of autosomes in the metaphases, but neither the X nor the Y are represented among the banded polytene chromosomes.

Key words: Ceratitis capitata, chromosomes (polytene), chromosomes (mitotic), salivary gland chromosomes.
Experimental comparison of restricted selection index and restricted independent culling levels in Tribolium castaneum
Authors: Campo J. L. , Villanueva B.
Published: April 2011

A selection index (I) method was compared with independent culling levels (N), with a restriction in the selection program, using two replicated single generation experiments in Tribolium castaneum, which are considered forms of antagonistic selection. The first experiment was designed to increase adult weight without changing pupal weight, while the second experiment was intended to improve egg laying without changing adult weight. In both experiments the genetic correlation between the traits involved were positive but were higher in experiment 1 than in experiment 2. The proportion of selection was 10%. In experiment 1, the effect of restriction was as expected in both lines since the changes in pupal weight were not significant. Adult weight change was positive for the I line and negative for the N line, showing that the index was a superior method to improve adult weight. In experiment 2, the effect of restriction was also as expected in both lines and changes in adult weight were not significant. Egg laying changed positively in both lines. Therefore, both selection methods were similar in this experiment, even though egg laying change was higher in the I than the N line.

Key words: restricted index, restricted culling levels, antagonistic selection, Tribolium.
Recombination block in the Spore killer region of Neurospora
Authors: Campbell Joseph L. , Turner Barbara C.
Published: April 2011

Spore killers Sk-2K and Sk-3K are chromosomal meiotic drive factors in Neurospora. In heterozygous crosses, ascospores not contining the Spore killer die. Sk-2K and Sk-3K, which differ in killing specificity, were found to be associated with suppression of recombination in a centromere-spanning region of linkage group III, and investigation of that recombination block is reported here. The block covers a region that is normally 30 to 40 map units long. A locus (r(Sk-2)) conferring resistance to Sk-2K maps to the left end of the recombination block. Recombination is normal in r(Sk-2) × Sk sensitive but blocked in Sk-2K × r(Sk-2); so the block does not depend upon killing. By selective plating, SkK stocks carrying genetic markers within the block were obtained at frequencies on the order of 10−5 or 10−6. Since this tight block is far beyond what has been observed for genetic reduction of recombination, a structural basis is assumed. No evidence of chromosome rearrangement was obtained. Crosses homozygous for Sk-2K show normal crossing-over and map order for the flanking markers cum and his-7 and three included markers (acr-7, acr-2, and leu-1). Results would be consistent with a divergence of sequence great enough to interfere with homologous pairing.

Key words: meiotic drive, Neurospora, crossover suppressor.
A cytogenetical study of 7-day-old bovine embryos of poor morphological quality
Authors: King W. A. , Guay P. , Picard L.
Published: April 2011

Seven-day-old embryos were collected from Canadian Holstein and Ayrshire heifers after superovulation with pregnant mare's serum gonadotropin (PMSG) or follicle-stimulating hormone (FSH). A total of 103 morphologically abnormal (type C) and 23 morphologically normal (type A) embryos were cytogenetically analyzed after 4, 20–24, or 44–48 h of culture in enriched phosphate-buffered saline or Eagles minimum essential medium. Twenty-one of 23 (91.3%) type A and 75 of 103 (72.8%) type C embryos had cells in metaphase. Among the 21 type C embryos produced by PMSG stimulation, 17 (80.9%) could be analyzed: 6 were mixoploid (two 2n/3n, three 2n/4n, one 2n/6n), 2 were aneuploid (61 XXY), and 9 were diploid. Among the 82 type C embryos produced by FSH stimulation, 58 (70.7%) could be analyzed: 6 were mixoploid (one n/2n, one 2n/3n, three 2n/4n, one 2n/4n/8n), 2 were polyploid (4n), and 50 were diploid. No abnormalities were observed in the type A embryos.

Key words: bovine embryo, chromosome, mixoploid, aneuploid.
Genomic affinities of individual chromosomes based on C- and N-banding analyses of tetraploid Elymus species and their diploid progenitor species
Authors: Morris K. L. D. , Gill B. S.
Published: April 2011

Giemsa C- and N-banding techniques were used to identify individual somatic chromosomes in the tetraploid (2n = 28) species Elymus trachycaulus (= Agropyron trachycaulum) (genome designation SH) and E. ciliaris (= A. ciliare) (SY) and five diploid progenitor species (2n = 14), Pseudoroegneria spicata (= A. spicatum) (S), P. libanotica (= A. libanoticum) (S), P. stipifolia (= A. stipifolium) (S), Critesion bogdanii (= Hordeum bogdanii) (H), and C. californicum (= H. californicum) (H). Comparisons based on banding patterns of E. trachycaulus and E. ciliaris with parental donor species P. spicata indicated a common S genome origin. The heterochromatin composition of several E. trachycaulus chromosomes were similar to chromosomes of both Critesion species. However, the possible origin of characteristic C- and N-banded chromosomes of E. ciliaris remained undetermined. These patterns of evolution among genomes of E. trachycaulus, E. ciliaris, and their progenitor species proved valuable for the allocation of individual chromosomes into specific genomes. This approach may be useful for the genomic allocation of wheat-Elymus addition lines.

Key words: C-banding, N-banding, Elymus, Triticeae, genome.
Certation between euploid and aneuploid pollen grains from a tertiary trisomic of rye, Secale cereale L.
Authors: Janse J.
Published: April 2011

Male transmission of the translocated extra chromosome 5R3R was studied in a tertiary trisomic of rye (Secale cereale L.) using two pollination densities. With abundant pollen, male transmission reached 4%. When a mean of four pollen grains were brought on every stigma (restricted pollination), a transmission rate of 20% was obtained. Seed set, mean seed weight, germination percentage, and the percentage of plants finally surviving were lower in the case of restricted pollination. It was concluded that certation between euploid and aneuploid pollen grains plays a decisive role in male transmission of the translocated chromosome. Although it was previously shown that aneuploid microspores have a delayed development, a large proportion must have reached maturity before anthesis. Therefore, genetic factors determining male transmission rate will primarily be expressed during pollen germination and tube growth rather than before anthesis.

Key words: rye, tertiary trisomic, euploid pollen grains, aneuploid pollen grains, certation.
Evolution of a mouse Y chromosomal sequence flanked by highly repetitive elements
Authors: Nishioka Yutaka , Lamothe Estelle
Published: April 2011

Mammalian primary sex is determined by the presence or absence of the Y chromosome. However, little is known about the molecular processes through which the Y chromosome exerts its action. We applied recombinant DNA techniques to isolate mouse Y chromosomal fragments and described previously a clone designated as AC11 (Y. Nishioka and E. Lamothe. 1986. Genetics, 113: 417–432). To obtain information on DNA sequences that flank AC11, we screened a mouse genomic library for the presence of AC11-related sequences and isolated over 50 positive clones. In this report we describe clones ACC2 and ACC3, both of which contain highly repetitive elements. Using a male-specific portion of these clones, we compared DNA's isolated from mice (Mus musculus, M. hortulanus, M. spretus, M. cookii, M. pahari, and M. platythrix), rat, hamster, and guinea pig and obtained results that agree with the phylogenetic relationships deduced from morphological and biochemical studies. The male-specific accumulation of the related sequences was found only in M. musculus, M. hortulanus, and M. spretus.

Key words: mouse, Y chromosome, repetitive sequence, genome evolution.
Intergeneric hybrids between Hordeum jubatum and triticale (×Triticosecale Wittmack)
Authors: Gupta P. K. , Fedak G.
Published: April 2011

Hybrids of Hordeum jubatum (4x) were produced with two isogenic lines of 6x triticale (×Triticosecale Wittmack) cv. DRIRA, one carrying the normal heterochromatic block on the long arm of 7R (cv. DRIRA HH) and the other lacking 90% of it (cv. DRIRA EE). The two hybrids were produced at relative frequencies of 1.1 and 0.9% of pollinated florets, respectively. The chromosome pairing in both of these hybrids was negligible (chiasmata frequencies 0.11 and 0.15), indicating that heterochromatin on 7R had no effect on chromosome pairing in H. jubatum and that the expected autosyndetic pairing between two related genomes of H. jubatum was absent in this combination.

Key words: wide crosses, intergeneric hybrids, triticale, Hordeum jubatum, chromosome pairing.
A spontaneous translocation that transfers wheat curl mite resistance from decaploid Agropyron elongatum to common wheat
Authors: Whelan E. D. P. , Hart G. E.
Published: April 2011

The wheat curl mite (Eriophyes tulipae Keifer) is the vector of wheat streak mosaic virus, a damaging disease of winter wheat. A translocation between a common wheat (Triticum aestivum L.) chromosome and a group 6 chromosome (6Ag) from decaploid Agropyron elongatum (Host) Beauv. resulted in transfer of resistance to colonization by the wheat curl mite. Transmission of resistance through the pollen and the egg were similar and not significantly different from 50%. The frequency of resistance in the F2 generation (65.6%) was lower than expected for a single, dominant gene. In the F2, 26.7% of the resistant plants were homozygous for resistance. Selfed progeny from monosomic and disomic F1 plants from crosses between the translocation line and monosomics for 6A and 6B segregated with frequencies similar to normal F2 progeny but the progeny of monosomics for 6D were primarily resistant (93.2%). Crosses between the translocation line and chromosome 6D telocentrics and studies of four enzymes that are encoded by genes on the group 6 homoeologous chromosomes showed that the translocated chromosome consists of the q arm of chromosome 6D of 'Rescue' and the p arm of chromosome 6 of A. elongatum. Because the new stock was derived from a double monosomic, the translocation was probably a Robertsonian fusion of misdivided centromeres. The resistance is being backcrossed into winter wheat.Key words: Agropyron elongatum, Thinopyron, Elytrigia, Lophopyrum, Robertsonian translocation, isozyme structural genes, wheat curl mite.
Transmission of a chromosome from decaploid Agropyron elongatum that confers resistance to the wheat curl mite in common wheat
Authors: Whelan Ernest D. P.
Published: April 2011

One of the group 6 chromosomes from Agropyron elongatum (Host) Beauv. confers resistance to colonization by the wheat curl mite (Aceria tulipae Keifer). The transmission of this chromosome was evaluated when added to or substituted for the group 6 homoeologues in two cultivars of common wheat (Triticum aestivum L.). Female transmission of the alien chromosome was similar for all substitutions (8.9%) but significantly less than expected. Male transmission (39.7%) differed among the substituted chromosomes and also was lower than expected except for the substitution involving chromosome 6A. These reduced transmission frequencies were reflected in lower than expected resistance in the F2 progeny. Both male (14.5%) and female (5.2%) transmission of the alien chromosome were reduced in monosomic additions. Meiotic analyses detected all expected F2 cytotypes but some of their frequencies differed among the substituted chromosomes. A possible wheat –alien translocation was detected in BC1F1 progeny.Key words: Agropyron elongatum, Thinopyrum, Elytrigia, Lyphopyrum, wheat curl mite, chromosome substitution.
Heterozygous inversions and spontaneous male crossing-over in Drosophila ananassae
Authors: Singh A. K. , Singh B. N.
Published: April 2011

Experiments were conducted to detect the effects of heterozygous inversions on spontaneous crossing-over in males of Drosophila ananassae by using a second chromosome triple recessive stock and four wild stocks. The karyotypic constitution of all the stocks was known. The occurrence of spontaneous male crossing-over has been observed in all the strains tested though the rate of recombination varies. The results show that crossing-over is completely absent between cu and b genes due to inversion heterozygosity in 2L. The males homozygous in 2L show crossing-over in both regions (cu–b, b–se). The inversion heterozygosity in 2L increases the rate of recombination between b and se genes. Furthermore, two third chromosome inversions, when heterozygous also increase crossing-over in the second chromosome. These results suggest that spontaneous male crossing-over in D. ananassae is affected by heterozygous inversions. Thus the present finding lends support to the earlier suggestion that spontaneous crossing-over in males of D. ananassae is meiotic in origin.Key words: Drosophila ananassae, heterozygous inversions, spontaneous male crossing-over.
Isozyme variation and inheritance in blueberry
Authors: Vorsa Nicholi , Manos Paul S. , Heemstra Maria I. van
Published: April 2011

Leaf tissue extracts from diploid, tetraploid, and hexaploid species of blueberry, Vaccinium section Cyanococcus, were electrophoretically analyzed for isozyme polymorphism in 12 enzyme systems. Aldolase, shikimate dehydrogenase, triose phosphate isomerase, glucose-6-phosphate dehydrogenase, phosphoglucomutase, aconitase, alcohol dehydrogenase, and aspartate aminotransferase showed activity, but banding was not clear. Four enzymes, malate dehydrogenase (MDH), phosphoglucose isomerase (PGI), 6-phosphogluconate dehydrogenase (6-PGD), and isocitrate dehydrogenase (IDH), exhibited interpretable banding patterns. Two loci were apparent for MDH, PGI, and 6-PGD and one for IDH. Polymorphism was detected at Mdh-2, Pgi-2, 6-Pgd-2, and Idh. Three allozymes were found at Mdh-2 and Idh and at least four at Pgi-2 and 6-Pgd-2. Allozyme segregation ratios observed in progeny of controlled diploid crosses supported single-gene Mendelian inheritance. Banding patterns of all allozymes indicated a dimeric structure for these four enzymes. It appears that all alleles at multiallelic loci are expressed in polyploids. Preliminary data suggest that allozyme analyses may be useful in taxonomic studies in blueberry.Key words: Vaccinium, allozymes, inheritance, electrophoresis.