bluuebunny/crossref_metadata_2025 huggingface dataset:
ALTERED STEROID INDUCED PUFFING BY CHROMATIN BOUND ALUMINUM IN A POLYTENE CHROMOSOME OF THE BLACKFLY SIMULIUM VITTATUM
Authors: Sanderson Catherine L. , McLachlan Donald R. Crapper , Boni Umberto De
Published: November 2014

The neurotoxic element aluminum accumulates selectively upon nuclear chromatin of several cell types, including neurons and glial cells of experimental animals and man. However, no mechanism of toxic action has been identified. Histometric analyses of the puffing patterns induced by ecdysterone in polytene chromosomes in the dipteran, Simulium vittatum (Zetterstedt) showed that chromosomes of salivary gland cells exposed to aluminum in vitro exhibit significant alterations in their response to ecdysterone. Specifically, chromatin bound aluminum completely inhibits (p < 0.05) puffing at seven out of nine sites normally puffed by ecdysterone and partially inhibits (p < 0.05) puffing at one site. Aluminum induces a partial puff (p < 0.05) at one site previously inhibited when both aluminum and ecdysterone were present. These findings suggest that one mode of toxic action of chromatin bound aluminum may be related to changes in gene expression.
INVITATIONAL PAPER: MELANOMA FORMATION IN FISH OF THE GENUSXIPHOPHORUS: A GENETICALLY-BASED DISORDER IN THE DETERMINATION AND DIFFERENTIATION OF A SPECIFIC PIGMENT CELL
Authors: Vielkind Jürgen , Vielkind Ursula
Published: November 2014

The formation of melanomas in Xiphophorus can be interpreted as a disorder in such fundamental biological processes as the determination and differentiation of cells. This disorder can be induced by outcrossing or by the mutation of genes that control these processes. In general, the conclusions drawn from the study of the development of a special pigment cell type in fish might be valid for many other tumors and might help us to understand the mechanisms leading to cancer in man.
CYTOLOGY OF CHROMOSOME II TRISOMICS AND A SPONTANEOUSLY DOUBLED TRISOMIC IN THE TUBER-BEARING SOLANUM SPECIES
Authors: Lee Heiyoung Kim , Hanneman Jr. R. E.
Published: November 2014

Solatium chacoense Bitt. clone V1682.1 and two of its F1 progeny were identified as primary trisomics for chromosome II on the basis of a pachytene analysis. The transmission frequency of the extra chromosome through the female gametophyte was 20% in V1682.1. Clone V1057.25, an interspecific hybrid involving S. maglia Schlechtd., S. microdontum Bitt. and S. tuberosum Gp. Phureja and Gp. Tuberosum, was identified as a secondary trisomic for the short arm of chromosome II. Another clone trisomic for chromosome II, V1057.46, which is a sib of V1057.25, and has been maintained by clonal propagation each year, spontaneously doubled and now has a chromosome number of 2n = 50. Chromosome pairing at metaphase 1, chromosome distribution at anaphase 1, and the number of microspores at the tetrad stage were studied. Male and female fertility of the trisomics, as measured by seeds per fruit, were satisfactory though not always correlated.
CYTOLOGY OF PASPALUM VIRGATUM AND ITS RELATIONSHIP WITH P. INTERMEDIUM AND P. JURGENSII
Authors: Burson Byron L. , Quarin Camilo L.
Published: November 2014

A cytological study revealed that Paspalum virgatum L. is sexual, meiotically stable, and has 2n = 4x = 40 chromosomes. Paspalum virgatum was crossed with P. intermedium Munro. ex Morong and P. jurgensii Hackel; both have 2n = 2x = 20 chromosomes. Six P. intermedium × P. virgatum, 2n = 3x = 30, hybrids were studied cytologically. Meiosis was irregular with a mean chromosome pairing of 11.68 univalents, 9.09 bivalents, 0.03 trivalents, and 0.002 quadrivalents per cell at metaphase I. This indicates that the two species have a homologous genome with some minute structural differences because some of the bivalents were not tightly synapsed. One hybrid, 2n = 3x = 30, was recovered from the P. jurgensii × P. virgatum cross. Meiosis was irregular with a mean pairing of 18.72 univalents, 5.70 bivalents, and 0.05 trivalents. These findings suggest that P. jurgensii and P. virgatum have a partially homologous genome. Because P. intermedium and P. jurgensii have the genome formulas II and JJ, respectively, the formula II J2J2 is proposed for P. virgatum.
INVITATIONAL PAPER MUTANTS OF YEAST MEIOSIS (SACCHAROMYCES CEREVISIAE)
Authors: Moens Peter B.
Published: November 2014

Mutants that affect the meiotic process in yeast are reviewed with an emphasis on structural phenotypes. By-pass of the normal nutritional requirements for entrance into meiosis: spd 1, cdc 25, cdc 35. By-pass of the a/α control: rme, CPS, sca. Mutants with little or no meiotic DNA synthesis: Mei 1, −2, −3, spo 7, −8, −9, cdc 8, −21, cdc 4, spo 11. Mutants with meiotic DNA synthesis (possibly defective): spo 1, cdc 2, con 1, cdc 7, spo 10, pac, rad 6, con 2, −3. Mutant with defective or modified kinetic functions: cdc 5, −14, spo 2, −3, −4, −5, −12, −13.
INHERITANCE OF ALLOZYME VARIANTS IN COASTAL DOUGLAS-FIR (PSEUDOTSUGA MENZIESII VAR. MENZIESII)
Authors: El-Kassaby Y. A. , Yeh F. C. , Sziklai O.
Published: November 2014

The inheritance of 27 loci from 18 enzyme systems was investigated using both megagametophyte and embryo tissues of open pollinated seed collected from a natural stand of coastal Douglas-fir [Pseudotsuga menziesii var. menziesii (Mirb.) Franco]. Four enzyme systems - glutamate dehydrogenase (GDH), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), mannose-6-phosphate isomerase (MPI), and peptidase (PEP) - appeared to be monomorphic and the remaining 14 systems - acid phosphatase (APH), aconitase (ACO), aspartate aminotransferase (AAT), diaphorase (DIA), esterase (EST), glucose-6-phosphate dehydrogenase (G6P), hexoseaminidase (HA), isocitrate dehydrogenase (IDH), malate dehydrogenase (MDH), malic enzyme (ME), phosphoglucose isomerase (PGI), phosphoglucomutase (PGM), 6-phosphogluconic dehydrogenase (6-PGD), and superoxide dismutase (SOD)-showed polymorphism. Each enzyme system was discussed with respect to its multilocus organization, subunit (quaternary) structure, and allelic variation.
ESTIMATION OF THE NUMBER OF GENES IN DOUBLED HAPLOID POPULATIONS OF BARLEY (HORDEUM VULGARE)
Authors: Choo T. M. , Reinbergs E.
Published: November 2014

It was shown that the number of segregating genes affecting a quantitative character in a single cross can be estimated by dividing the square of the deviation of the most extreme doubled haploid from the sample mean by the genotypic variance of doubled haploids. The number of segregating genes was estimated for three characters in four crosses of barley (Hordeum vulgare L.). It was found that the number of segregating genes for grain yield, heading date, and plant height ranged from 5 to 11, 6 to 9, and 4 to 13, respectively.
STRAIN AND SEX DIFFERENCES IN SERUM ALPHA-FETOPROTEIN LEVELS INMUS MUSCULUS
Authors: Pollard D. R. , Woodward B. , Gupta Kamlesh
Published: November 2014

Normal levels of circulating serum alpha-fetoprotein (AFP) in different inbred strains of mice, as determined by radioimmunoassay, are reported. These strains show different and characteristic values for the mean serum AFP concentration, suggesting genetic control of the serum level of this protein. Furthermore, within each strain a difference in serum levels of the protein is observed between sexes; males have a significantly higher serum AFP concentration.
A PERENNIAL × ANNUAL MEDICAGO CROSS
Authors: Sangduen N. , Sorensen E. L. , Liang G. H.
Published: November 2014

We successfully crossed perennial Medicago sativa L. (2n = 4x = 32) and annual M. scutellata (L.) Mill. (2n = 4x = 32). The hybrid was a mixoploid. The primary shoot was hexaploid. Later a tetraploid shoot was identified and another tetraploid shoot had a distinct flower color (dark purple). Somatic chromosome number was unstable, which probably led to chimeral sectoring. Chromatographically the hybrid was documented by species-specific phenolic substances. The hybrid was perennial, but color of the vegetative parts and stem number of the hexaploid sector resembled the annual parent. Flower color of the hexaploid was purple like the perennial; the short peduncle and self-tripping mechanism were like the annual. Leaflet number was unstable, varying from 2 to 6 per leaf. Several characters were intermediate between the parents. Pollen stainability of the hexaploid was low, and no seed was obtained from selfing, backcrossing to either parent, or crossing to Chilean and nondormant M. sativa plants. Other sectors of the mixoploid will be characterized as material becomes available.
CYTOLOGY AND FERTILITY OF PENTAPLOID WHEAT HYBRIDS WITH INDUCED PAIRING BETWEEN HOMOEOLOGOUS CHROMOSOMES
Authors: Kushnir U. , Halloran G. M.
Published: November 2014

Two mutants, each promoting homoeologous chromosome pairing in hexaploid wheat (Triticum × aestivum L. emend gr. aestivum), in the cultivar Chinese Spring, ph1bat the Ph locus on chromosome 5BL and the other, ph2, on chromosome 3DS, were compared for their influence on chromosome pairing and fertility in pentaploid hybrids with Triticum turgidum L. emend var. dicoccoides (Korn. in litt. in Schweinf.). The mutants induced increased multivalent frequency over the normal pentaploid. Lower univalent frequencies in the ph2-pentaploid, compared with the normal pentaploid, indicated that D-genome chromosomes of the former were substantially involved in homoeologous pairing. Certain differences in other meiotic processes and fertility among the pentaploids may reflect differences in the activity of the pairing genes. There appeared to be a higher level of univalent elimination in pollen and egg cells in the ph2-, compared with the ph1b-pentaploid. Tetrad formation was close to normal in the ph2- pentaploid but exhibited high levels of abnormality (monads, dyads, triads and apolar tetrads) in the ph1b-pentaploid. Fertility levels in crosses of the pentaploids with hexaploid wheat, while low, were much lower for the ph1b-, compared with the ph2-pentaploid.
INHERITANCE OF BRANCHED RACEME AND CAULIFLOWER CHARACTERS IN ALFALFA
Authors: Kinoshita Toshiro , Suginobu Ken-Ichi
Published: November 2014

The inheritance of the branched raceme character in alfalfa (Medicago saliva L.) was studied. In the segregation of inflorescence types, the cauliflower type with vestigial flowers appeared in the segregating population together with the branched raceme and normal types. According to the inheritance patterns observed in F2, F3, F4 and test cross, it was postulated that a single recessive tetrasomically inherited gene is responsible for both types of inflorescence; the genotypes for branched raceme and cauliflower types were designated as simplex (Aaaa) and nulliplex (aaaa), respectively. Various segregation ratios obtained in the progenies from inter-crossings and backcrossings were explained consistently due to the possible combination of the genotypes used for the parents. Test crossings between cauliflower and normal types also demonstrated the simple tetrasomic inheritance in F2 populations under random chromosome assortment. It was determined that the branched raceme character used for the experiments possesses the heterozygous simplex genotype (Aaaa).
THE TEMPORAL RESPONSE OF RECOMBINATION EVENTS TO GAMMA RADIATION OF MEIOTIC CELLS INSORDARIA BREVICOLLIS
Authors: Lewis Leslie A.
Published: November 2014

The temporal frequencies of different stages of prophase I were determined cytologically in Sordaria brevicollis (Olive and Fantini) as the basis for ascertaining the degree of synchrony in meiosis in this ascomycete. Croziers, karyogamy-zygotene and pachytene asci were shown to be in significant majorities at three distinct periods of the meiotic cycle. The response of recombination frequency to ionizing radiation was examined for the entire meiotic cycle. Three radiosensitive periods were determined. This response, which correlated temporally with each of the three peaks in ascal frequency, is interpreted as showing that the meiotic cycle of this organism is divided into periods of recombination commitment (radiation reduced frequencies) during the pre-meiotic S phase and recombination consummation (radiation induced frequencies) during zygotene and pachytene. The results are discussed in the context of the time at which recombination is consummated in eukaryotes such as yeast and Drosophila.
UNUSUAL VARIATIONS IN NUCLEAR DNA CONTENTS IN THE MARINE COPEPODPSEUDOCALANUS
Authors: Robins Judith H. , McLaren Ian A.
Published: November 2014

Variations in DNA/nucleus within adult females are similar, when normalized for mean differences, in the copepods Pseudocalanus sp. and Eurytemora herdmani. However, Pseudocalanus shows great variation among individuals, with no evidence of significant groupings (species?), except perhaps for a few individuals with abnormally small DNA values. Body lengths of adult female Pseudocalanus are approximately proportional to the cube root of DNA/nucleus. It is inferred that nuclear size, not nuclear number, determines body size, and this is supported by generally similar nuclear counts in newly hatched nauplii and among first copepodid stages. Although body size and development rate of Pseudocalanus had earlier been shown to be strongly heritable, an offspring-parent regression reflected no heritability of DNA/nucleus (and some abnormally small offspring values) under the probably suboptimal conditions of rearing. Some variability in DNA content of adult somatic nuclei may be related to chromatin diminution during embryogenesis. An unusual loss of nonchromosomal, Feulgen-positive material is documented for first cleavage in Pseudocalanus, but not E. herdmani.
A DURUM WHEAT DISOMIC-SUBSTITUTION LINE HAVING A PAIR OF CHROMOSOMES FROMTRITICUM BOEOTICUM: EFFECT ON GERMINATION AND GROWTH
Authors: Joppa L. R. , Maan S. S.
Published: November 2014

Durum wheat selection 56-1 was crossed with an accession of Triticum boeoticum Boiss.; and a F2plant had 13 pairs plus 2 univalents (13″ + 2′) at metaphase I. In subsequent generations, plants with the chromosome configuration 14″ + 1′ were selected. Plants with 14″ + 1′ produced two types of seed. Approximately 78% of the seeds had purple pericarp and the rest were amber. Purple seeds failed to germinate unless they were soaked overnight in a one mg/l solution of gibberellic acid (GA3). The seeds with purple pericarp had 28 chromosomes including a pair of T. boeoticum chromosomes which were substituted for a pair of 4B chromosomes from durum wheat. The disomic-substitution plants were dwarfs and male-sterile. Amber seeds had the chromosome constitution 13″ + X″ + 4B′ (X = the T. boeoticum chromosome) and produced male-fertile, normal height plants. Chromosome pairing relationships indicated that the T. boeoticum chromosome had no more homology with wheat chromosomes 4A, 4B, and 4D than they had with each other. The T. boeoticum chromosome compensated for the loss of durum chromosome 4B except for a locus affecting GA.
WHITE EYE AND CURLED, RECESSIVE MUTANTS ON THE X CHROMOSOME OF ANOPHELES ALBIMANUS
Authors: Seawright J. A. , Benedict M. Q. , Narang S. , Kaiser P. E.
Published: November 2014

Two new mutants, white eye (we) and curled (cr), of Anopheles albimanus Wiedemann were isolated and studied. Both mutants are recessive and are approximately 18.9 ± 1.9 units apart on the X chromosome. White eye is fully viable, but cr is a recessive lethal. The mode of inheritance of these two mutants provides further evidence of an X-Y sex determination system in An. albimanus and a lack of homology between the X and Y chromosomes.
A TECHNIQUE FOR LIGHT AND ELECTRON MICROSCOPY OF THE SYNAPTONEMAL COMPLEX OF THE MOUSE OOCYTE
Authors: Sung Weng Kong , Jagiello Georgiana
Published: November 2014

A method is described for obtaining synaptonemal complex preparations from mouse pachytene oocytes for light and electron microscopic examination. A karyotype based on the whole complement of synaptonemal complexes of a pachytene oocyte as visualized by electron microscopy is presented.
ÉTUDE BIOMÉTRIQUE DU CARYOTYPE DE LA BRUCHE DU HARICOT (ACANTHOSCELIDES OBTECTUS, COLÉOPTÈRES, BRUCHIDAE)
Authors: Garaud P. , Lecher P.
Published: November 2014

The karyotype of a European strain of the bean beetle, Acanthoscelides obtectus, has been made using biometrical methods with two parameters: arm ratio and relative length; each chromosome is defined by two values. Graphic representation of all chromosomes gave well scattered points. This method allowed us to determine the diploid number (2n = 20), sex mechanism (XY/XX) and the establishment of a definite karyotype. This study is part of an ongoing comparative analysis of strains from various geographical origins.[Translated by the journal]
SPONTANEOUS ANEUPLOIDS OF MAIZE (ZEA MAYS) IN A SELECTED SAMPLE
Authors: Ghidoni A. , Pogna N. E. , Villa N.
Published: November 2014

A maize (Zea mays L.) sample with a high frequency of spontaneous aneuploids was prepared by selecting seeds and plants. The study was carried out on seeds discarded during the mechanical processing of a commercial hybrid. Starting from a discarded bulk of 20,000, a selected fraction of about 4,000 small and malformed kernels was planted in the field. Further selection was made by examining the developing plants and their pollen. A group of 46 plants was selected because of relatively high pollen sterility or abnormal plant growth and subjected to genetic investigation. After crossing these plants to inbred lines, 14 of them (about 30%) produced aneuploids among the offspring; a few of these aneuploids were cytologically identified as primary trisomics. The high pollen sterility was not associated with the aneuploid condition. This finding suggests that selection was made for structurally altered chromosomes whose behavior during the meiotic process gave rise to aneuploids.
DIFFERENTIAL SURVIVAL AS AN INDICATOR OF POTENTIAL MUTAGENICITY USING REPAIR DEFICIENT STRAINS OFSACCHAROMYCES CEREVISIAEANDSCHIZOSACCHAROMYCES POMBE
Authors: Nestmann Earle R. , Stephen Eric R. , Kowbel David J. , Nasim A.
Published: November 2014

A method is presented to screen chemicals for potential mutagenicity on the basis of their ability to cause more killing in cells of repair-deficient yeast than in wild type cells. Two species were chosen in the event that one might be more sensitive to certain chemicals. The strains used were RAD+and rad6 derivatives of Saccharomyces cerevisiae and RAD+and rad3 derivatives of Schizosaccharomyces pombe. This report describes the test system and results for 12 known, direct-acting mutagens (i.e., not requiring mammalian metabolic activation). These compounds showed more lethality in one or both of the repair-deficient strains, indicating that they induce damage to DNA which is subject to repair in wild type cells. Advantages of this system include the use of eukaryotic yeast cells which can be manipulated as easily as bacteria, and that exogenous enzymes (S9) can be added for metabolic activation. Growing yeast cells can activate certain promutagens, and preliminary experiments showed positive responses for diethylnitrosamine and 2-acetylaminofluorene without the addition of S9.
Chromosome numbers of 15 North American bumble bee species (Hymenoptera, Apidae, Bombini)
Authors: Owen Robin E.
Published: November 2014

Chromosome counts were obtained for 14 Bombus Latr. species (the social bumble bees) belonging to four subgenera and for one Psithyrus Lep. species (the social parasitic bumble bees). In Bombus the haploid numbers were consistent within each subgenus and there was variation between subgenera; the subgenera Bombus s.s. and Pyrobombus have n = 18, while Separatobombus and Cullumanobombus have n = 19. Thus considerable morphological divergence between subgenera is often, but not always, paralleled by divergence in chromosome number. Psithyrus ashtoni has n = 25, higher than all Bombus species yet examined. This provides support for the monophyletic origin of Psithyrus, but the high n is not expected if eusociality selects for increase in chromosome number.
Inheritance of virulence of Ustilago nuda on the barley cultivars Warrior, Compana, Valkie, Keystone, and Bonanza
Authors: Thomas P. L.
Published: November 2014

A hybrid between two biotypes of Ustilago nuda (Jens.) Rostr. produced segregating progeny that were used to identify two genes for virulence on five cultivars of barley. Gene Unv1 was responsible for virulence on 'Warrior,' 'Compana,' and 'Valkie' while gene Unv2 was responsible for virulence on 'Keystone' and 'Bonanza'. The two genes were recessive and inherited independently from each other and from the loci for mating type and spore color.
Allozyme variability and evolution of lodgepole pine (Pinus contorta var. latifolia) and jack pine (P. banksiana) in Alberta
Authors: Dancik Bruce P. , Yeh Francis C.
Published: November 2014

not available
Haploids in Triticum ventricosum via intergeneric hybridization with Hordeum bulbosum
Authors: Fedak George
Published: November 2014

Haploids were induced in Triticum ventricosum Ces. following intergeneric hybridization with Hordeum bulbosum L. (2n = 4x = 28) at a frequency of 8% of pollinated florets. The average chiasma frequency in the polyhaploids was 0.46 indicating negligible homoeology between the component genomes (DvMv).
The characterization of a mutant affecting DNA metabolism in the development of D. melanogaster
Authors: Stone J. C. , Dower N. A. , Hauseman J. , Cseko Y. M. T. , Sederoff R.
Published: November 2014

Using a "single-fly" nucleic acid hybridization method, we have surveyed a collection of D. melanogaster strains in search of variants which affect DNA complementary to the polypyrimidine sequence corresponding to one strand of the 1.705 satellite. Hybridization of labelled polypyrimidine probe to polypurine sequence in nucleic acid extracts of single flies, followed by thermal chromatography over hydroxyapatite led to the identification of one variant. The strain Cy/M(2)S210 produced excess hybrid, much of which had low thermal stability. A developmental analysis of the low-melt hybrid phenotype showed that certain tissues, in particular the ovaries, were affected. In addition to the biochemical phenotype, the break down of nurse cell nuclei in Cy/M(2)S210 ovaries during oocyte maturation was abnormal. A genetic analysis demonstrated that both the biochemical and cytological phenotypes were the consequences of a single recessive mutation in the DNase-1 gene on chromosome III. Studies with purified DNA demonstrated that the low-melt hybrid phenotype resulted from the accumulation of low molecular weight DNA complementary to the polypyrimidine probe.
Genetic analysis of quantitative characters in cigar and pipe tobacco, Nicotiana tabacum. III. Economic indices: grade index, yield, and crop revenue
Authors: Ogilvie I. S. , Kozumplik V.
Published: November 2014

A diallel cross of four cigar cultivars and one pipe tobacco (Nicotiana tabacum L.) cultivar was analyzed for the following parameters: grade index, yield, crop revenue or index, percentage of nicotine, percentage of total alkaloids, and susceptability to pole rot. The experiment was performed over 3 years. Analysis was done for general combining ability and specific combining ability. General combining ability was greater than specific combining ability for all variables although significant specific combining ability effects were also present for all parameters with the exception of nicotine and total alkaloids. Reciprocal effects were completely absent. The line Pennbel 69 showed a positive general combining ability effect for yield, crop index, and infestation by pole rot and a high negative general combining ability effect for grade index and percentage of nicotine and total alkaloids. Petit Havane showed a complete reverse of general combining ability effects for these parameters while the other three cultivars were intermediate. High positive specific combining ability effects for grade index, yield, and crop index and high negative specific combining ability effects for the percentage of pole rot were shown by crosses of Pennbel 69.
Light intensity as a factor in the choice of an oviposition site by Drosophila pseudoobscura and Drosophila persimilis
Authors: Wogaman Dennis J. , Seiger Marvin B.
Published: November 2014

Light preferences for ovipositing of the sibling species Drosophila pseudoobscura and D. persimilis were measured in a multichoice chamber. Behavioral differentiation was found among sympatric populations of D. pseudoobscura and D. persimilis and between allopatric populations of D. pseudoobscura. Differences among isofemale lines within populations indicated genetic variability for the behavior. Both D. pseudoobscura populations were less fecund in a uniform light environment than in the multichoice environment while D. persimilis showed no difference in fecundity in the two environments. The patterns for general photoresponse and ovipositional light response were shown to be different for each population. Thus, the motivation to oviposit may affect photopreference differentially in each population.
Telomere arrangement in differentiated interphase cells of Allium cepa: a function of chromosome arm lengths at anaphase–telophase
Authors: Fussell Catharine P.
Published: November 2014

The arrangement of telomeres in eight types of differentiated Allium cepa L. interphase cells was studied to find whether the distribution pattern varies with differentiation as centromere distribution appears to in differentiated cells of mice and Triturus vulgaris L. The results show that telomere positions and groupings in A. cepa are essentially the same in differentiated and meristematic interphase nuclei; telomeres, which are roughly paired, are arranged in a telophase configuration along one side of the nucleus. Thus telomeres appear to maintain the same basic arrangement in differentiated and in meristematic cells. Comparison of chromosome arm lengths and interphase telomere positions suggests that interphase telomere arrangements are a function of chromosome arm lengths at the time the nuclear envelope forms. Such an arrangement would place homologous telomeres in the same latitudinal band of the interphase nucleus.
Polarization of the honey bee gynandromorphic blastoderm
Authors: Milne Jr. Charles P. , Rothenbuhler Walter C.
Published: November 2014

Honey bee (Apis mellifera L.) gynandromorphs arise because one or more accessory sperms, which normally degenerate, develop into male tissue. Twenty-two external morphological structures were examined in 1555 gynandromorphs from 8 gynandromorph-producing queens. The frequency with which a structure was male (percent male) and its longitudinal position on the blastoderm fate map were examined for each structure. When grouped by body region, there were no significant differences between the head, thorax or abdomen in the frequency at which a structure was male. In the head region, a significant relationship was discovered between the frequency that a structure was male and its longitudinal location on the blastoderm (r = −0.884, F = 35.76, degrees of freedom (DF) = 1 and 10, p < 0.0001). A reasonable contour map of the blastoderm was prepared showing the regions with comparable frequency of structures being found male. The compound eye (73.9%) and lateral ocellus (63.9%) were the structures most frequently male. The mouthparts, for example the labial palp (24.5%), showed the least frequency of being male. A hypothesis based upon previous cytological observations was formulated to explain these results. The diploid zygotic nucleus, which will form the female tissue of a gynandromorph, is near the primordia for the mouthparts when it initiates cleavage. Most of the time the mouthparts primordia on the blastoderm are populated by female cells, and the adult structures are most often female. The compound eye and lateral ocellus primordia are near the cephalic pole where the haploid accessory sperm(s) begin division.
Environmental induction of high frequency 2n pollen formation in diploid Solanum
Authors: McHale N. A.
Published: November 2014

Ten genotypes of Solanum phureja Juz. and Buk. producing 2n pollen via fused (FS) and tripolar (TPS) spindles at the second meiotic division were grown in 2 consecutive years at a cool field site (E1, 8–22 °C) and in a warm greenhouse (E2, 14–40 °C) to examine environmental effects on mean frequency and phenotypic stability of 2n pollen production. Overall frequencies of big pollen (BP) and dyad formation were substantially higher in E1 in both years. The stable standard (154-1) gave almost complete expressions of dyads in E1, with no bud below 99%. Four other genotypes (413, 414, 416, 417) gave a similar response in E1, producing mean dyad frequencies between 93 and 99%, with no bud below 80%. The other four genotypes (420, 424, 427, 429) and the variable standard (127–14) produced higher dyad frequencies in E1 versus E2, but their phenotypes remained variable in E1, showing disparities up to 79% between buds of a single collection. The fidelity of stable and variable phenotypes in E1 was examined by scoring dyad frequencies in putatively stable (413, 414, 415, 416) versus variable (420, 424, 427, 127–14) genotypes at four dates spanning the flowering period in this environment. The four stable genotypes showed consistent expression of high dyad frequency (86–99%) at all four dates. In contrast, dyad frequencies of the variable genotypes were substantially lower and more variable between and within collections.
The effect of rye genotype on wheat–rye crossability and on the development of F1 seed
Authors: Scoles Graham J.
Published: November 2014

Five inbred lines of rye (Secale cereale L.) and an open-pollinated rye cultivar were used to pollinate wheat (Triticum aestivum L.) cultivars of differeing crossability. No hybrid seed was produced with the cultivar of low crossability, but with the highly crossable cultivar an average seed set of 65% was obtained. Significant differences in terms of seed set and weight of F1 seed were detected among the inbreds.
Genetic mapping in the Mexican axolotl, Ambystoma mexicanum
Authors: Armstrong John B.
Published: November 2014

In the Mexican axolotl, Ambystoma mexicanum, gynogenetic diploids can be produced by suppressing the release of the second polar body in eggs activated with irradiated sperm. If the female is heterozygous for a particular mutation, some of the progeny will be homozygous for the mutation. The proportion depends on the distance from the centromere and can be used to determine the gene–centromere (or gene–kinetochore) distance. The mapping function is based on the Neurospora tetrad mapping function. Several variations on this function, based on considerations of how coincidence varies with map distance, are considered. Three genes have been mapped: c at 5.9, t at 24.3, and m at 59.1 map units from their respective centromeres. Four other genes (a, ax, p, and the sex locus) appear to be distant from their centromeres but precise map distances cannot be determined. Based on these data, the total length of the genome has been estimated as at least 2600 map units.
Cytology and breeding behavior of interspecific hybrids and induced amphiploids of Zinnia elegans and Zinnia angustifolia
Authors: Terry-Lewandowski Veronica M. , Bauchan Gary R. , Stimart Dennis P.
Published: November 2014

Cytological studies were performed on interspecific hybrids and induced amphiploids of Zinnia angustifolia HBK (2n = 22) and Zinnia elegans Jacq. (2n = 24) to ascertain their potential in serving as intermediaries in the transfer of genes for disease resistance. Partial fertility was restored in sterile F1 hybrids (2n = 23) through colchicine treatment of axillary buds. Lagging univalents and irregular distribution of chromosomes to the gametes were the major contributing factors to the sterility observed among the F1 hybrids. Bivalent associations in the F1 indicated partial homology between parental genomes. The induced amphiploids (2n = 46) formed predominantly bivalents at metaphase I owing to the suppression of pairing between homoeologous chromosomes. Consequently, these segmental allopolyploids resembled diploids in their cytological and genetic behavior and bred true to their intermediate condition with little or no segregation in later generations. It is postulated that the gene(s) controlling chromosome pairing is derived from Z. elegans. The cytological and genetic performance of colchicine-induced amphiploids of Z. elegans and Z. angustifolia suggest considerable potential for the improvement of Z. elegans cultivars with respect to disease resistance and the immediate stabilization of characters through genetic uniformity.
Effects of interacting genetic factors and temperature on meiosis and fertility in soybean × Glycine soja hybrids
Authors: Ahmad Q. N. , Britten E. J. , Byth D. E.
Published: November 2014

Hybrids between the soybean, Glycine max (L.) Merrill, and the wild Glycine soja Sieb. and Zucc. exhibited marked differences in chromosome behaviour and fertility, depending on parentage of the hybrids and temperature of the culture. Meiosis in some F1 hybrids was regular, while in others the frequency of pollen mother cells (PMCs) with irregularities ranged up to 44%. Degeneration of pollen and seed was not, however, always proportional to meiotic irregularity. The results from glasshouse and controlled environment studies suggest that at least three factors were influencing chromosome behaviour and fertility. These factors were genotype, temperature, and genotype–temperature interaction. An aspect of practical significance arises where off-season nurseries are used to increase seed in which gene transfer is expected. If temperatures at the site are suboptimal for chromosome pairing and chiasmata formation, the operation may be selfdefeating. These results also have implications in studies in which the affinity of two taxa is being determined by chromosome behaviour of the hybrid between them. Unless crosses involve a number of parents with different genetic constitutions and are studied under a range of temperatures, the results may be misleading.
Genetic control of swimming stamina in Atlantic salmon (Salmo salar)
Authors: Hurley S. M. , Schom C. B.
Published: November 2014

A rigorous regime was used to test fish stamina in a stress tunnel. The heritability of swimming stamina was 0.24. The genetic correlation of −0.14 with length was small and negative, while the environmental correlation of 0.43 was larger. This can be taken to imply a relatively small additive component affecting swimming with the possibility of dominance deviation in the correlated responses.
Gametocidal genes in wheat and its relatives. I. Genetic analyses in common wheat of a gametocidal gene derived from Aegilops speltoides
Authors: Tsujimoto H. , Tsunewaki K.
Published: November 2014

Alloplasmic lines of 12 common wheats carrying G-type cytoplasm derived from an aucheri-type strain of Aegilops speltoides show about 50% reduction of female fertility compared with the alloplasmic lines of the same common wheats carrying G-type cytoplasms from other sources. This reduction of female fertility is caused by a gametocidal gene derived from Ae. speltoides. This gene has been preferentially transmitted through 16 successive backcrosses in which common wheat was the recurrent pollen parent, and has been present in the heterozygous state in every backcross generation. The karyotype and meiotic chromosome pairing of hybrid from reciprocal crosses between (Ae. speltoides) – cv. Chinese Spring and (Triticum aestivum) – cv. Chinese Spring are normal, indicating that the gametocidal gene derived from an Ae. speltoides chromosome subsequently was translocated to a wheat chromosome. This is the first case reported of the integration of a gametocidal gene into a wheat genome; the symbol given to it is Gcl. The F1 female and male gametes not carrying this gene abort and, consequently, all F2 progeny are homozygous for the gene and fully fertile. The origin and distribution of the Gcl gene and its potential use for hybrid wheat production have been discussed.
Chromosome engineering in triticale
Authors: Kaltsikes P. J. , Gustafson J. P. , Lukaszewski A. J.
Published: November 2014

Triticale has been treated as a botanical oddity until the past few years when it has become accepted as a commercial cereal crop. This paper assesses the improvements that have been made to triticale through chromosome manipulation and modification. In addition, insights into further chromosome manipulations are discussed.Key words: heterochromatin, triticale, chromosome pairing, endosperm.
The inheritance of resistance to race 56 of stem rust in 'Marquillo' wheat
Authors: Knott D. R.
Published: November 2014

The common wheat (Triticum aestivum L.) cultivar 'Marquillo' was crossed and backcrossed to 'Marquis,' and was also crossed with the 'Chinese Spring' monosomics. Seedlings from the F2 families from the backcross and from F2 and F3 families from the crosses with the monosomics were tested with race 56 of stem rust (Puccinia graminis tritici Eriks. and Henn.). The results indicated that 'Marquillo' carries a single recessive gene for resistance to race 56, located on chromosome 3B. The gene which was identified as Sr12, appears to be temperature sensitive and was affected by a recessive modifier.Key words: wheat, Triticum aestivum, Puccinia graminis, monosomics, rust resistance.
The influence of wheat–rye parental species on the protein characteristics of primary triticale
Authors: Virdi B. V. , Larter E. N.
Published: November 2014

The influence of parental tetraploid wheats (Triticum turgidum L.) and diploid ryes (Secale cereale L.) of predetermined protein content on the protein characteristics of derived hexaploid (2n = 6x = 42) triticale amphidiploids (× Triticosecale Wittmack) was investigated. Although the two parental species contributed independently to the protein content of the derived triticale. the maternal wheat parent had a greater influence than did the rye parent. Thus, triticales derived from combinations of wheat × rye of "high × high" protein content were themselves of high protein content, followed in descending order of protein by "high × low," "low × high." and "low × low" combinations. The difference in protein content of triticales derived from the reciprocal combinations of the wheat–rye protein groups (i.e., high × low versus low × high) was significant. Polyacrylamide gel electrophoretic analyses of extracted prolamine from the triticale amphidiploids and their parents revealed that polymorphism can exist in the protein banding patterns of any given population. As expected, the degree of polymorphism was greatest in those triticale populations synthesized from open-pollinated heterozygous rye strains, but polymorphism was also seen within some amphidiploid populations derived from inbred (S6–S8) parental ryes. For purposes of biological studies, it is important to recognize the genetic heterogeneity that can still exist within populations of plant species and their hybrids assumed to be genetically and chromosomally stable.Key words: × Triticosecale Wittmack, protein electrophoresis, wheat–rye hybrids, amphidiploids.
Sibling species and sex chromosome differentiation in Simulium neornatipes (Diptera: Simuliidae)
Authors: Bedo D. G.
Published: November 2014

Polytene chromosome analysis of five Simulium neornatipes populations not only confirms the existence of the two sibling species, S. neornatipes 1 and 2, proposed earlier but reveals a third. S. neornatipes 3. These sibling species share a common standard polytene chromosome banding sequence which differs from the Australian S. ornatipes complex standard by five fixed inversions. The sharing of polymorphic inversions between the ornatipes and neornatipes complexes indicates their close relationship. The neornatipes species are distinguished from each other by additional fixed inversions and differentiated sex chromosomes. Extensive sex chromosome differentiation involving chromosome III has occurred in S. neornatipes 1 and 2. A period of incomplete sex-linkage allowing reassortment of inversions must have preceded the currently observed strong sex-linkage of differentiated sex chromosomes to account for the complex array of sex chromosomes found. The close association of sex chromosome differentiation with speciation in black flies is discussed in relation to appropriate speciation mechanisms. It is concluded that the rearrangements themselves have no direct role in the speciation process.Key words: sibling species, sex chromosomes, Simuliidae.
Structure, orientation, and segregation of the sex trivalent in Pyrophorus luminosus III. (Coleoptera, Elateridae)
Authors: Virkki N. , Flores M. , Escudero J.
Published: November 2014

An endemic Puerto Rican Elaterid, Pyrophorus luminosus III., has 17 chromosomes in the male, the meiotic karyoformula being 7 + X1X2Y, or as expressed structurally, 7 + XpneoXneoYp. Xp is heteropycnotic in prophase and differentially argentophilous from prophase to metaphase II. The parachute of a modified shape is only slightly stained by AgNO3 and by Rattenbury's nucleolus staining method.Key words: Elateridae, Pyrophorini, sex chromosomes, sex trivalent.
Genetic differences for size and shape in inbred lines of Poecilia reticulata
Authors: Vanelli Maria Luisa , Rocchetta Gabriella , Pancaldi Carlo
Published: November 2014

The model of K. Mather is applied to partition the mean phenotypic expression of the "size" and "shape" traits during the growth in inbred lines and their F1 generations of Poecilia reticulata. In particular, the dynamics of the environmental and interaction components during growth have been analyzed. The results obtained for the "shape" show that the genotype – environment interaction is proportional to the effect of the environment so that the genetic differences evaluated for this trait are amplified in the last age considered. On the other hand, the lack of this kind of relationship, estimated for the size trait, and a greater weight of the environmental component, suggest that it is not possible to identify a particular age at which genetic differences between lines could be more easily detectable for this trait within the range analyzed.Key words: Poecilia, quantitative.
Chromosome instability in Coix gigantea Koen. (Maydeae)
Authors: Nirmala A. , Rao Panuganti N.
Published: November 2014

In Coix gigantea Koen. (2n = 20), six of the plants that survived in the progenies raised from seed collected from Madhya Pradesh showed wide intraplant variation in chromosome number and behaviour. The chromosome number varied from 2n = 7 to 29. Higher configurations involving up to 10 chromosomes were found, though associations of 3 and 4 chromosomes were more prevalent. Univalents were also fairly common. Further, chromosome fragments ranging from one to three per cell were found in several of the cells. Similar variations in chromosome number and fragments were also observed in tapetal cells. Chromosomal associations and chiasma frequency were studied in each of the chromosome classes. Laggards, ranging from one to five were observed at anaphase I and II. Pollen grains were polymorphic and completely sterile, and there was no seed set. The instability was considered as part of the genomic plasticity, coupled with polyploidy, serving to enlarge the cytogenetic diversity in the species. However, it occurs in this population to levels beyond the tolerance limits of the genome affecting the fitness of the individual.Key words: Coix, chromosomal variation.
Induction of G-bands in the chromosomes of Melanoplus sanguinipes (Orthoptera, Acrididae)
Authors: Zhan T. S. , Pathak S. , Liang J. C.
Published: November 2014

Pretreatment of embryos of a nondiapause strain of the migratory grasshopper (Melanoplus sanguinipes) with actinomycin D, followed by posttreatment of chromosome preparations obtained from them with NaOH and Sörenson's buffer, induced longitudinal differentiation of each chromosome after Giemsa staining. We consider such crossbands to be G-bands because of the following: (i) they were present along the entire length of each chromosome; (ii) the centromeric region of each chromosome was unstained; (iii) each pair of chromosomes showed its own distinctive banding pattern; (iv) the banding pattern was consistent from cell to cell for the same pair of chromosomes; and (v) a similar procedure is known to induce G-bands in human chromosomes. C-bands induced by the Ba(OH)2 technique showed constitutive heterochromatin to be confined to the centromeric region of each chromosome.Key words: Melanoplus, G-bands.
Allozyme variation, population structure, and sibling species in Aphis pomi
Authors: Singh Rama S. , Rhomberg Lorenz
Published: November 2014

Apterous apple aphids (Aphis pomi de Geer) collected from several southern Ontario orchards in several seasons were studied electrophoretically for 17 enzyme and 2 protein loci. Sixteen loci proved monomorphic. The remaining three showed a strong association among loci; all individuals that are homozygous for the fast allele of glutamate oxaloacetate transaminase (Got) also have no esterase-1 activity (presumably being fixed for a null allele) and have a unique banding phenotype for esterase-2 (a locus for which no Mendelian model could be made). The remaining aphids are fixed for the slow Got allele, have two active alleles segregating at esterase-1 and show either of two banding phenotypes at esterase-2. Apparently. Aphis pomi consists of two differentiated, noninterbreeding subpopulations. The first type has increased from rarity to near fixation in southern Ontario since 1978, and may be spreading up the Niagara Peninsula. It has greater resistance to malathion than the replaced type.Key words: aphid, allozymes, population genetics, polymorphisms, speciation.
The taxonomy of multivalent orientation: six modes of alternate or one?
Authors: Sybenga J.
Published: November 2014

Unlike adjacent I and II, alternate I and II orientations of interchange and tetrasome quadrivalents can be considered extremes within one particular population of orientations (alternate) and thus lack sufficient distinction to justify a separate taxonomic status. Within the population up to six types may be distinguished, but the biological significance of this distinction is small.Key words: multivalent, alternate orientation, adjacent orientation, chiasmata.
Linkage betwen the male sterility gene (ms1) and a translocation breakpoint in soybean, Glycine max
Authors: Sacks Jerome M. , Sadanaga Kiyoshi
Published: November 2014

The F2 distribution of male sterility (ms1) and flower color (w1) in a cross between translocation 172-11-3 (W1W1Ms1Ms1) and A77-139 (w1w1Ms1ms1) in soybean, Glycine max (L.) Merr., was highly abnormal. Duplicate-deficient and 41-chromosome progenies constituted 32% of the F2 population. The w1, and ms1 loci are located on the translocation exchange chromosomes designated T1 and T2, respectively. Evidence from other translocations suggests that linkage group 8 (LG8) is located on the single satellited normal chromosome designated NI. The breakpoint lies between the ms1 and w1, loci with recombination values of 18.4 ± 3.3% and 2.0 ± 1.2%, respectively.Key words: linkage, translocation, soybean, Glycine.
Evidence of nonchiasmate bonds at metaphase I in inbred rye
Authors: Cermeño M. C. , Orellana J. , Lacadena J. R.
Published: November 2014

The loss of bound chromosome arms through early, middle, and late metaphase I has been analyzed in a plant of inbred rye (Secale cereale L.) heterozygous for a terminal heterochromatic C-band of the long arm of chromosome 1R. From the increase in the number of univalent pairs due to bound arm loss, and from the comparison between the frequencies of bound arms at metaphase I and recombinant chromosomes at anaphase I, it is concluded that some of the chromosome bonds appearing at metaphase I are actually nonchiasmate associations that can be considered as remnants of prophase pairing. Conclusions concerning recombination obtained solely from the analysis of chiasma frequency measured as bound arms may be invalid.Key words: inbred rye, C-heterochromatin, meiotic pairing, nonchiasmate bonds.