bluuebunny/crossref_metadata_2025 huggingface dataset:
INFLUENCE OF CYSTEAMINE ON DIFFERENTIAL STAINING OF BUdR-SUBSTITUTED HUMAN CHROMOSOMES
Authors: Scheid W.
Published: November 2014

In 5-bromodeoxyuridine (BUdR)-substituted human chromosomes stained with 4′-6-diamidino-2-phenylindole (DAPI) differential staining is suppressed totally by the H+-donor cysteamine (concentration 0.08 M). We propose that differential staining appears because the double BUdR-substituted chromatid will be disintegrated via a photosensitive dye-visible light system. It is suggested that cysteamine prevents the production of strand breaks in DNA and, consequently, differential staining in BUdR-substituted chromosomes. Furthermore it is shown that differential staining with DAPI causes irreversible changes in the double BUdR-substituted chromatid. This finding can be explained with the above mentioned mechanism.
THE INHERITANCE OF RED-EYE, A SEX LINKED MUTANT OF THE AEDES SCUTELLARIS COMPLEX (DIPTERA: CULICIDAE)
Authors: Trpis Milan
Published: November 2014

Red-eye is a new mutant in the Aedes scutellaris complex of mosquitoes. The mutation is detectable in three developmental stages: larvae, pupae, and adults. In the larval stage only centrally located ommatidia of the compound eyes are red. In the pupal stage only ventro-laterally located ocelli are red; compound eyes are pigmentless. Shortly before the emergence of adults, the compound eyes of the pupae turn light red. Red-eye was isolated from Aedes sp. 'Tafahi', but is easily transferable to other members of the Ae. scutellaris complex by laboratory cross-breeding procedures. Survival of (re) is high, penetrance is complete and expressivity of red color is variable in intensity. The red-eye character is controlled by a single recessive gene linked to sex. The linkage distance between sex (M/m) and (re) locus estimated from both F2 and backcross data is 15.3 ± 2.7 map units.
MEIOSIS AND POLYPLOIDY IN ONTARIO SPECIES OFCRATAEGUSIN RELATION TO THEIR SYSTEMATICS
Authors: Muniyamma M. , Phipps J. B.
Published: November 2014

Chromosome number determinations of 68 accessions of about 20 species in 11 series of Crataegus (hawthorn), Rosaceae, occurring in southern Ontario are presented. This is the first extensive documentation of chromosome numbers in North American Crataegus since Longley's (1924) account which was based on sectioned material. Our results, taken in the context of our cytological work proving the presence of apomixis in the genus, and taxonomic studies, clearly establish that in Ontario Crataegus is part of an extensive agamic complex consisting of diploids (2n = 34), polyploids (3x and 4x) and some aneuploids. Cytological observations of the triploids (2n = 51) and tetraploids (2n = 68) that have indicated the occurrence of meiotic irregularities and various degrees of pollen sterility in some of the polyploid taxa studied, underline the significance of apomixis in Crataegus evolution. One of the common Ontario species, C. punctata, is shown to be a probable sexual diploid and further cytological work should now be concentrated on particular species complexes.
CHROMOSOME PAIRING AND FERTILITY OF F1 HYBRIDS OF AEGILOPS LONGISSIMA AND AE. SEARSII
Authors: Feldman Moshe , Strauss Ilana , Vardi Aliza
Published: November 2014

The recently described Aegilops searsii Feld. &Kis. is morphologically closely related to Ae. longissima Schweinf. et Muschl. The cytogenetic affinity of these two species was estimated by studying karyotypes, chromosomal pairing, pollen fertility and seed set in parental lines and in intra- and inter-specific F1 hybrids. Pairing in Ae. longissima × Ae. searsii hybrids was incomplete and indicative of several structural rearrangements of parental chromosomes. The hybrids were highly sterile, indicating that the two species are well isolated from one another by internal chromosomal and genetic barriers. These isolating mechanisms are superimposed upon strong ecological specialization of each species. The data further support the validity of the specific rank of Ae. searsii and indicate that it contains a distinct genome which was designated Ss.
STUDIES ON THE DEVELOPMENTAL CHARACTERISTICS OF FUSED MUTANTS OF DROSOPHILA MELANOGASTER
Authors: Wurst Glen G. , Hanratty William P.
Published: November 2014

The development of the lethal and visible effects of 16 independently arising fused mutations was studied. No complementation was observed in any of the 120 heteroallelic combinations of fused mutations. Temperature shift experiments indicated that there is coordinance of expression of all the pleiotropic fused effects, with regard to both temperature sensitive period and degree of expressivity. These studies showed that the expressivity of both the lethal and visible fused effects are directly related to pupal developmental time spent at the restrictive temperature. Gynandromorph studies indicated that all visible effects of the fused mutation develop autonomously and that the thoracic effects are localized in the posterior part of the anterior developmental compartment of the wing disc. These data support the conclusion that the fused locus contains a single functional unit. The data also suggest that the fused gene is expressed simultaneously in each affected tissue of the fly and that the fused product may perform a similar function in each affected part of the fly.
ANALYSIS OF MAIN STEM AND SIDE SHOOT WEIGHT FOR CYTOPLASMIC EFFECTS IN CROSSES BETWEEN FLAX GENOTROPHS AND GENOTYPES
Authors: Tyson H.
Published: November 2014

Certain genotypes of flax are susceptible to the level of inorganic nutrients supplied in the soil; heritable changes may be induced in a genotype, resulting in 'genotrophs' which behave as distinct genetic types. Two contrasting genotrophs and two other genotypes were intercrossed. For any two parents and their reciprocal F1 hybrids, crosses were made in all combinations to yield 16 different progenies from each of the four genotroph-genotype and one genotroph-genotroph combination. Cytoplasmic effects were then examined both within and across these segregating generations, in terms of the differences stemming from the use of the two reciprocal F1's as sources of either male or female gametes. Models were fitted by weighted least squares procedures to estimate genetic parameters and cytoplasmic effects. Cytoplasmic effects on both side shoot and main stem weight were transmitted through the male gametes to the progenies of each genotroph in crosses with the other two genotypes.
HORDEIN VARIATION IN WILD (HORDEUM SPONTANEUM) AND CULTIVATED (H.VULGARE) BARLEY
Authors: Doll Hans , Brown A. H. D.
Published: November 2014

The storage protein hordein contains two major groups of polypeptides which are highly polymorphic in barley, and in its evolutionary progenitor Hordeum spontaneum Koch. Crosses between the two species showed that the complex electrophoretic phenotypes within the two groups of polypeptides are governed by codominant alleles at two corresponding loci, Hor-1 and Hor-2, which are moderately linked (11% ± 2). In natural populations of the wild species, the two complex hordein loci were much more polymorphic than the allozyme loci. Furthermore, the variation at these two loci was highly correlated so that individuals differ from one another at both loci much more frequently than expected from the allele frequencies at the individual loci. Considerable hordein variation was also present in Composite Cross XXI, and there was evidence of reassortment of patterns by the seventeenth generation. Thus the complex hordein loci, with their extreme diversity and linkage disequilibrium, are ideal markers for monitoring evolutionary processes in both natural, or composite cross populations.
THE GENETICS OF FERTILITY RESTORATION IN CYTOPLASMIC MALE-STERILE RYE
Authors: Scoles G. J. , Evans L. E.
Published: November 2014

Three inbred lines of rye (Secale cereale L.) known to be capable of restoring fertility to a cytoplasmic male-sterile line were crossed with the sterile line. The proportions of male fertile, partially male fertile and male sterile plants in F2 and backcross progenies indicated that three dominant restorer genes were present in each line. These were designated Rf1, Rf2 and Rf3, their relative expressivity was Rf1>Rf2>Rf3. Expressivity was dependent upon environment. Partial fertility occurred when certain genotypes carried two of the three alleles as dominant, but was dependent upon genotype and environment.
THE INFLUENCE OF THE PO1A1 MUTATION UPON RECOMBINATION IN ESCHERICHIA COLI K12
Authors: Glickman Barry W. , Rutgers Tineke
Published: November 2014

Genetic recombination in Escherichia coli is a highly regulated process involving multiple gene products. We have investigated the role of DNA polymerase I in this process by studying the effect of the po1A1 mutation upon DNA transfer and conjugation in otherwise isogenic suppressor-free strains of E. coli K-12. It was found that the po1A1 mutation greatly reduces recombination in Hfr crosses (a factor of 20 in Po1+ × Po1A1 crosses and more than a factor of 100 in Po1A1 × Po1A1 crosses). However, since the po1A1 mutation reduces the strains capacity to act as a recipient for an F-prime and the analysis of recombination transfer gradients revealed no differences between Po1+ and Po1− strains, it is concluded that DNA polymerase I probably affects the transfer and/or stability of donor DNA rather than the recombinational process itself.
THE ORGANIZATION OF GENETIC VARIABILITY IN CENTRAL AND MARGINAL POPULATIONS OF LODGEPOLE PINEPINUS CONTORTAspp.LATIFOLIA
Authors: Yeh F. C. , Layton C.
Published: November 2014

A survey was conducted of genetic variation at 25 loci in extracts of individual megagametophytes of lodgepole pine. Collections were made in nine widely separated localities representing four marginal, two intermediate and three central populations. Single populations of lodgepole pine were, on the average, polymorphic at 58.67% of their loci, and had 1.90 alleles per locus. Both expected and observed heterozygosity averaged 0.16. There was a definite trend towards decreased genetic variability at the margins. The measures of gene diversity for the 25 loci showed a 4% but significant effect of interpopulation differentiation; 96% of the total gene diversity resided within populations. Estimated outcrossing rates [Formula: see text] for the nine populations ranged between 0.92–1.29. Comparisons among populations with different levels of outcrossing revealed no clear relationship between [Formula: see text] and amount of genetic variability. The overall pattern of genetic differentiation agrees with expectations based on the neutral mutation theory. However, two loci demonstrated conspicuous clinal variation patterns which may be incompatible with this stochastic model.
CYTOLOGY OF 2n POLLEN FORMATION IN DIPLOID ALFALFA, MEDICAGO SATIVA
Authors: Vorsa Nicholi , Bingham E. T.
Published: November 2014

Four diploid (2x) clones of alfalfa, Medicago sativa L., which produced good seed set when used as male parents in 4x-2x crosses were selected for study. The 2x clones descended from 2x haploids of cultivated 4x alfalfa. Fertility in the 4x-2x cross was due to the production of pollen with the unreduced chromosome number (2n pollen) from the 2x parent. The cytological mechanism of 2n pollen formation was found to be disorientation of spindles at metaphase II in up to 38% of the pollen mother cells. Thus, both n and 2n pollen were produced by all four diploids examined. Normal spindles at metaphase II were oriented such that they defined the poles of a tetrahedron and resulted in normal tetrads in a tetrahedral arrangement. Disoriented spindles were basically parallel to each other and resulted in formation of dyads and occasionally a triad. Dyads developed into two 2n pollen grains; triads developed into one 2n and two n pollen grains. Since both n and 2n pollen grains are produced by the diploids, they can be maintained as diploids or they can be used as male parents in crosses to tetraploids. The genetic constitution of 2n pollen resulting from parallel spindles is similar to that expected after first division restitution of meiosis and much of the heterozygosity of the diploid parent is conserved in the gametes. The 2n gamete mechanism has potential application in germplasm transfer and in maximizing heterozygosity in tetraploid hybrids.
ELECTROPHORETIC VARIANTS OF α-GLYCEROPHOSPHATE DEHYDROGENASE IN THE FIRE ANTSOLENOPSIS INVICTA
Authors: Hung Akey C. F. , Dowler Megan G. , Vinson S. Bradleigh
Published: November 2014

αGPDH exists in the fire ant Solenopsis invicta Buren in two isozymic forms representing two loci. The two isozymic forms are tissue specific and differentially expressed in different developmental stages as well as physiological states. GPDH-2 is monomorphic. GPDH-1 is polymorphic with fast and slow alleles. Clear differences in resistance to heat and urea denaturation were observed both between and within the two mobility classes.
CYTOGENETICS OF A BARLEY × RYE HYBRID
Authors: Fedak George
Published: November 2014

A viable hybrid with a somatic chromosome number of 14 was obtained by crossing Hordeum vulgare L. with Secale cereale L. Chromosome pairing in the hybrid was very low with an average chiasma frequency of 0.22. Phenotypically the hybrid resembled rye, the pollen parent, but the nucleolar characteristics were similar to barley.
SHORT-LIVED MUTAGEN IN SALMONELLA PRODUCED BY REACTION OF TRICHLOROACETIC ACID AND DIMETHYL SULPHOXIDE
Authors: Nestmann Earle R. , Chu Ih , Kowbel David J. , Matula Tibor I.
Published: November 2014

A chemical reaction occurs when trichloroacetic acid (TCA) is dissolved in dimethyl sulphoxide (DMSO), with the production of a short-lived mutagenic derivative which was detected using the Salmonella/mammalian-microsome plate overlay assay. Other interactions between test chemicals and solvents are discussed. Choice of proper solvents in mutagenicity testing is emphasized.
CHROMOSOME VARIATION AND EVOLUTION IN TRILLIUM GRANDIFLORUM
Authors: Fukuda I. , Grant W. F.
Published: November 2014

Chromosome analyses using cold-induced banding patterns were carried out on 25 wild populations of Trillium grandiflorum (Michx.) L. throughout the natural range of the species. Banding patterns were fairly uniform within and between populations with the exception of those occurring in chromosome D which varied from three to five times more than the other chromosomes. This is different from the situation in the western North American species T. ovatum Pursh. in which chromosome C is the most variable and the Japanese species T. kamtschaticum Pall. in which chromosome A is the most variable. There was greater homogeneity of karyotypes in northern populations than in southern ones. Supernumerary chromosomes were found in four of the 25 populations. In one plant the karyotype had been altered by a spontaneous translocation which has produced two new chromosome variants.
PRODUCTION, MORPHOLOGY AND MEIOSIS OF RECIPROCAL BARLEY-WHEAT HYBRIDS
Authors: Fedak George
Published: November 2014

The intercrossing of wheat (Triticum aestivum L. cv. Chinese Spring) and barley (Hordeum vulgare L. cv. Betzes) yielded hybrids at a frequency of 0.80% of pollinated florets for the barley-wheat combinations and 0.23% for the reciprocal cross. An increase in homoeologous pairing of wheat chromosomes was observed in both hybrids compared with the pairing observed in wheat haploids indicating that the barley genome had pairing promoting properties. Cytological abnormalities such as hyperploid meiotic cells and isochromosomes were attributed to abnormalities at premeiotic mitosis.
DEMONSTRATION OF A PARASEXUAL CYCLE IN THE ENTOMOPATHOGENIC FUNGUS METARHIZIUM ANISOPLIAE
Authors: Al-Aidroos K.
Published: November 2014

In an attempt to demonstrate the existence of a parasexual cycle in the imperfect entomopathogenic fungus, Metarhizium anisopliae (Metschnikoff) Sorokin, doubly- and triply-marked strains were forced to form heterokaryons. All heterokaryons produced diploid spores, two of which yielded putative recombinants.
CHROMOSOME LOCATION OF TWO LEAF RUST RESISTANCE GENES TRANSFERRED FROM TRITICUM SPELTOIDES TO T. AESTIVUM
Authors: Dvořák J. , Knott D. R.
Published: November 2014

Two homoeologous-recombination-produced gene transfer lines in which leaf rust resistance genes from Triticum speltoides Tausch were incorporated into the chromosome complement of Triticum aestivum L. emend. Thell. were analyzed. One line, F-7-3, originated from the cross T. aestivum cv. Neepawa × T. speltoides accession F and the other line, E-11-14, originated from the cross T. aestivum cv. Manitou × T. speltoides accession E. The lines were crossed with Chinese Spring monosomics. Segregation of the F2 progenies from monosomic F1's indicated that both genes were on chromosome 1B. The lines were then crossed with Chinese Spring ditelosomics 1BS and 1BL and the F1, plants were testcrossed to Manitou. Meiotic chromosome pairing in the F1 plants and the segregation of the telosomes and resistance in the testcrosses provided evidence that both gene transfers involved chromosome arm 1BL. The exchange points showed 41% and 4% recombination with the centromere in F-7-3 and E-11-14, respectively. Recombination between the transferred alien chromatin and the chromatin of the recipient wheat chromosome is either severely reduced or entirely absent when the wheat diploidizing mechanism is active.
YELLOW: A MUTANT PLUMAGE COLOR, SEGREGATING INDEPENDENTLY FROM BROWN, IN JAPANESE QUAIL
Authors: Roberts C. W. , Fulton J. E.
Published: November 2014

Two birds of Japanese quail (Coturnix coturnix japonica) with "yellow" plumage were found in a brown feathered population hatch. The trait was demonstrated to be due to the heterozygous condition of a single, dominant, autosomal gene (Y). The Y/Y genotype was found to be lethal presumably at a very early stage of embryonic development. A backcross test of 994 observations indicated that the loci for the brown and yellow plumage traits were inherited independently. The yellow feathered gene may also act as a partially dominant lethal with approximately 10% mortality.
THE GENETICS OF DIABETES MELLITUS IN MAN
Authors: Simpson Nancy E.
Published: November 2014

The genetics of diabetes mellitus in man has been reviewed. The evidence for genetic heterogeneity on clinical, biochemical and HLA (histocompatibility leukocyte antigens) data is presented. An attempt is made to interpret the meaning of the associations of the disease and certain HLA antigens and the complement factor, properdin in populations and in families. The population data can be best explained by the linkage disequilibrium hypothesis requiring tight linkage between the DS (diabetes susceptibility) locus and those in the MHC (major histocompatibility complex). Linkage between the DS locus and MHC from family data is estimated to be about 14%, which is not likely tight enough to be compatible with the population data; and a one locus or one allele hypothesis and genetic heterogeneity is postulated as the best explanation of the incompatibility between population and family data. It is still impossible to precisely define the exact genetic hypothesis for diabetes in man.
ON THE INHERITANCE OF INTERSEXUALITY IN SWINE
Authors: Sittmann K. , Breeuwsma A. J. , Brake J. H. A. te
Published: November 2014

Data of Breeuwsma (1970) were analyzed in an attempt to discriminate between major gene vs. multifactorial modes of inheritance of intersexuality in swine. Of 3708 females, 160 were intersexes with external phenotypes ranging from normal female (normal overlap) to testicular pseudohermaphrodite. Environment (litter size, parity, hormone treatment of dam) influenced detection of carriers but not origin of intersexes. Normal overlaps lowered penetrance, partly due to deaths in competition with male littermates. Phenocopies (intersex with unusual genotype or with karyotype other than 38,XX) were rare. Sex ratio variation between mating types could be ascribed to the ascertainment method. Segregation ratio estimates for female sibships increased from those with at least one to those with at least two intersexes less than expected for polygenic inheritance. The latter could not be ruled out (heritability of liability by three methods was 78%), but duplicate epistasis provided a more parsimonious explanation. Separation of litters from retrospectively known carriers into identifying and post-identifying groups produced patterns of segregation estimates supporting inheritance by few rather than many genes. Crossbred intersexes indicate homology of genes for intersexuality in several European breeds of pigs.
REDUCTION OF CHROMOSOME PAIRING BY A SPONTANEOUS MUTATION ON CHROMOSOMAL ARM 5DL OF TRITICUM AESTIVUM
Authors: Viegas Wanda S. , Mello-Sampayo T. , Feldman Moshe , Avivi Lydia
Published: November 2014

In a plant of Triticum aestivum L. em. Thell. cultivar Chinese Spring which was disomic for a mutant isochromosome of the long arm of chromosome 5D (di-isosomic 5DLM), partial chromosome asynapsis was detected at meiosis. Chromosome pairing in F1 hybrids from crosses of T. aestivum plants carrying the mutant isochromosome with Secale cereale, an intermediate pairing line of T. longissimum and with T. sharonensis disclosed that 5DLM carried a gene that reduced homoeologous chromosome pairing. This gene, designated Ph3 is less potent than its assumed homoeoallele on chromosomal arm 5BL, i.e., Ph1. The possibility of Ph1 being transferred from 5BL to 5DL through homoeologous chromosome pairing and recombination was discarded. Rather, it seems more likely that this allele resulted from a spontaneous mutation of the pairing-promoter allele known to be located on 5DL.
CHANGES IN CHROMOSOME NUMBER IN MICROSPORE CALLUS OF RICE DURING SUCCESSIVE SUBCULTURES
Authors: Chen Chi-Chang , Chen Chung-Mong
Published: November 2014

Forty-six callus cultures of rice (Oryza sativa L., 2n = 24), each presumably originating from a single microspore, were established and maintained on a medium containing 2,4-D. At the end of the first transfer 24% of the cultures were nonhaploid consisting of only diploid or polyploid cells, or of cells of two ploidy levels. Nuclear fusion and endomitosis occurring during the initial stages of in vitro microspore development were postulated to account for the formation of nonhaploid callus. Seventeen cultures were studied cytologically through 19 transfers. Only in one tetraploid and one hexaploid callus did the ploidy levels of cells remain unchanged during culture. Chromosome numbers in 13 cultures fell into a geometric series. Since no diplo- and quadruplochromosomes were observed, it was inferred that endomitosis rather than endoreduplication was responsible for the changes. In spite of the tendency for chromosome doubling, the proportions of cells of different ploidy levels were fixed in the 13 cultures at later transfers. Haploid cells were eliminated from all cultures. Diploid cells became predominant in eight cultures and tetraploid cells in five, suggesting a selection for either cell type. Triploids appeared in two cultures which initially did not contain this type of cell. Limited cytological information indicated that triploid cells might have originated from tetraploid cells through reductional grouping of chromosomes accompanied by multipolar formation.
GENETICS SOCIETY OF CANADA AWARD OF EXCELLENCE LECTURE: THE GENETICS OF COMMON FAMILIAL DISORDERS — MAJOR GENES OR MULTIFACTORIAL?
Authors: Fraser F. C.
Published: November 2014

The common familial disorders were, until recently, neglected by geneticists because their familial distributions did not neatly fit the Mendelian mold, and no specific genes could be identified. The multifactorial-threshold model made the familial characteristics of these disorders more intelligible. Although it originally postulated a polygenic genetic component the model can also accommodate one or more major genes with low penetrance. The resulting upsurge of interest has led to (1) the development of increasingly sophisticated mathematical models from which to calculate recurrence risks for specific family situations and (2) the identification of specific predisposing genes in a number of such disorders. One of the corollaries of the model is that any pharmacological agent at therapeutic doses is likely to be teratogenic to at least some embryos, so that regulation should be in terms of "acceptably low" levels of teratogenicity rather than "safety".
ELECTROPHORETIC VARIATION IN FOUR FRENCH POPULATIONS OF DOMESTICATED RAINBOW TROUT (SALMO GAIRDNERI)
Authors: Guyomard René
Published: November 2014

Electrophoretic variation of 12 enzyme systems, representing 26 loci in four strains of domesticated rainbow trout (Salmo gairdneri Richardson) were studied. The variances among and within strains, estimated from observed frequencies, were compared to data of other studies of biochemical polymorphism carried out in this species. These preliminary results show that a large proportion of the variability in rainbow trout is present in the French hatchery stocks studied and that isolation of these groups for several generations has not caused a significant genetic differentiation as compared to all the domesticated strains studied.
THE CHROMOSOMAL BASIS OF VIABILITY IN INTERSPECIFIC HYBRIDS BETWEENDROSOPHILA ARIZONENSISANDDROSOPHILA MOJAVENSIS
Authors: Zouros E.
Published: November 2014

The chromosomal effects on differences in viability among progeny from interspecific crosses was studied in the interfertile pair Drosophila arizonensis and Drosophila mojavensis. Interspecific crossing-over was avoided by crossing hybrid males to pure-species females, and chromosomal identification in backcross progeny was possible by means of electrophoretic markers. The main findings are as follows. One chromosome supresses viability when in the heterospecific state, this being mainly so when the rest of the genotype is predominantly of mojavensis type; the other chromosomes show occasional interspecific heterosis, but are neutral in the majority of cases; interactions are not significant, except in one pair of chromosomes within a mojavensis background; there is no correlation between numbers of heterospecific chromosomes and viability scores. It is concluded that hybrid and backcross progeny inviability is not a very potent mechanism for keeping these species apart. Should etiological and ecological barriers break down, introgressive hybridization is a real possibility. The findings are compared with those from studies concerning hybrid sterility and mating behavior in these two species. It is concluded that there is no common chromosomal basis for these phenomena. In particular, the role of interspecific inversions to speciation remains obscure.
GENETICS OF GROWTH RATE IN OYSTERS AND ITS IMPLICATIONS FOR AQUACULTURE
Authors: Singh Shiva M. , Zouros E.
Published: November 2014

Two samples of one-year-old American oysters (Crassostrea virginica Gmelin) obtained from the same inlet two years apart and grown under identical conditions were analyzed for their weight distribution and electrophoretic profiles at several enzyme loci. Although growth in the two years was significantly different, the electrophoretic profiles of the two populations were remarkably similar. On both occasions heterozygosity was positively correlated with mean weight and negatively correlated with the coefficient of variation. In general there was a deficiency of heterozygotes. This deficiency was more pronounced in the slow-growers than in the fast-growers. These observations suggest that growth rate (a limiting factor in current oyster aquaculture) can be improved by genetic manipulation. Use of large scale electrophoretic survey in providing guidelines for genetic improvement are discussed.
CYTOGENETICS OF SOME NATURAL INTERGENERIC HYBRIDS BETWEEN ELYMUS AND AGROPYRON SPECIES
Authors: Sadasivaiah R. S. , Weijer J.
Published: November 2014

The occurrence of natural interspecific hybrids between Elymus and Agropyron species was detected and verified by cytomorphological studies. The hybrids were highly vigorous and resembled Elymus species in vegetative growth habit, although their spikes were sterile, and intermediate between the putative parents in morphology. Chromosome pairing in the hybrids was highly irregular with 14 to 28 univalents per cell. The formation of up to seven bivalents, with mean frequencies of 2.86 to 3.14 per cell in different hybrids, was attributed to homoeologous relationships existing between the genomes of E. innovatus (JJXX) and those of Agropyron species (SSHH).
GENETIC CONTROL OF BODY TRAITS AND GROWTH PATTERN IN LEBISTES
Authors: Vanelli M. Luisa , Pancaldi Carlo , Alicchio Rita , Palenzona Domenico
Published: November 2014

Genetic variability and growth pattern of metric traits were studied in inbred lines of Lebistes reticulatus (Peters) obtained by crossing full sibs in three generations. Sub-sublines with different growth rates of body length and body weight were identified; on the whole inbred population a genetical analysis was performed for both traits at different ages on raw data and on data adjusted for growth rate regression. Both analyses reveal the presence of a great amount of genotype—environment interaction and of a certain amount of genetic variation for body traits. The differences concerning the genetic components of variation observed in the two analyses within each population indicate an influence of the different growth rates of sub-sublines on the detection of genetic variability.
THE EFFECTS OF GENOTYPE AND TEMPERATURE ON THE RESISTANCE TO PUCCINIA GRAMINIS TRITICI CONTROLLED BY THE GENE Sr6 IN TRITICUM AESTIVUM
Authors: Knott D. R.
Published: November 2014

A line of wheat (Triticum aestivum L.). Kenya 58/10* Marquis (K58Mq10), homozygous for gene Sr6 for resistance to stem rust (Puccinia graminis tritici Eriks. and Henn.), was crossed with four rust susceptible cultivars or lines. The F1 seedlings were tested with rust races 56 and 15B-1, twice under greenhouse conditions and three times in growth chambers, and F2 seedlings were tested twice in the greenhouse. In conditions that resulted in maximum resistance, Sr6 was dominant with both race 56 and race 15B-1 in two crosses, dominant with race 56 and recessive with race 15B-1 in one cross, and recessive with both races in the fourth cross. Thus, the dominance of Sr6 depended on the susceptible parent with which K58Mq10 had been crossed. The data indicated that the dominance of Sr6 was not controlled either by a single independent modifier locus or by the general genetic background of the susceptible parents. Although the possibility of a linked modifier has not been eliminated, it appears that the results may be due to the effects of different alleles for susceptibility at the Sr6 locus. The degree of resistance conditioned by Sr6 is determined by a complex interaction between genotype and environment.
HUMAN CHROMOSOMAL HETEROMORPHISMS IN AMERICAN BLACKS. IV. INTENSITY VARIATION IN CENTROMERIC REGIONS OF CHROMOSOMES 3 AND 4
Authors: Verma Ram S. , Dosik Harvey
Published: November 2014

One hundred normal American Blacks were studied by Q-banding technique in order to estimate the type and frequency of heteromorphisms in the centromeric regions of chromosomes 3 and 4. Heteromorphisms were classified using the scale of five intensity levels namely, negative, pale, medium, intense and brilliant fluorescence. QFQ intensity heteromorphisms [Formula: see text] for chromosomes 3 and 4 were 54.5 and 7%, respectively. The distribution of different intensities was significantly different in American Blacks compared with Caucasians.
THE EFFECTS OF PRETREATMENT OF SYNCHRONIZED CHO CELLS WITH 5-BUdR AND TdR ON CHROMOSOMAL DAMAGE AND CELL DEATH
Authors: Bhambhani R. , Kuspira J.
Published: November 2014

Chinese hamster ovary (CHO) cell populations were exposed independently to thymidine (TdR) or 5-bromodeoxyuridine (5-BUdR) for either one cell generation (approximately 18 h) or two (36 h) and subsequently synchronized in mitosis either by chemical arrest with colcemid or by mechanical shaking. Upon subsequent X-irradiation at various stages in the cell cycle, the synchronized populations were analyzed for cellular lethality and chromosomal damage. This investigation confirmed that each radiation response was "age-dependent" and essentially similar for both methods of synchrony. Cells irradiated in mitosis were found to be most radio-sensitive while cells irradiated during the DNA synthesis stage were most radio-resistant. A comparative analysis revealed that the two responses of radiation were more pronounced for cells labelled with 5-BUdR than they were for TdR-labelled cells. A further enhancement of radiation responses was noted for cells that were grown in the presence of the halogenated pyrimidine analog for two cell generations, thus re-affirming that the nucleus is a primary target for radiation damage. The comprehensive conclusion sought with regard to the degree of correlation between chromosomal damage and loss of cellular reproduction integrity awaits such information as the molecular organization of mammalian chromosomes and the mechanisms by which aberrations are produced within these chromosomes.
ANEUPLOID ANALYSIS OF A GENE FOR LEAF RUST RESISTANCE DERIVED FROM THE COMMON WHEAT CULTIVAR TERENZIO
Authors: Dyck P. L. , Kerber E. R.
Published: November 2014

The LrT gene for resistance to leaf rust present in the common wheat (Triticum aestivum L.) backcross line RL 6049, and originally derived from the cultivar Terenzio, was shown to be on chromosome 4B. Farther analysis indicated that it is on the long arm of this chromosome, 2.9 ± 1.3 crossover units from the centromere. It is independent of or loosely linked with Sr7a, a gene for stem rust resistance known to be on the long arm of chromosome 4B. It is inherited independently of leaf rust resistance genes Lr1, Lr2a, Lr3, Lr10, Lr14b, Lr16, Lr17 and Lr18. LrT has been redesignated Lr30.
GENETIC STUDIES OFEUDORINA ELEGANS(CHLOROPHYCEAE)
Authors: Kemp C. Lindley
Published: November 2014

Procedures have been established for sexual induction and germination in the alga Eudorina elegans (Ehrenberg). Gamete induction occurs following nitrogen removal and zygospores are germinated following drying. A series of mutants have been crossed using these procedures. Ten ac-dependent strains isolated from a single enrichment experiment represent seven or eight independent loci. Four independently isolated nitrogen metabolism mutants also represent different loci. In contrast, three independently isolated nicotinamide requiring mutants and two independently isolated para-aminobenzoic acid requiring mutants appear to affect single loci. Streptomycin resistance was transmitted exclusively by the female parent.
INSECT CHROMOSOME ISOLATION: A METHOD FOR METAPHASE CHROMOSOME HARVEST FROM CULTURED CELLS OF THE MOSQUITO AEDES ALBOPICTUS
Authors: Mukherjee Asit B. , DeGiorgio Lorraine
Published: November 2014

A modified technique for bulk isolation of metaphase chromosomes from an in vitro cell line of the mosquito Aedes albopictus (Skuse) is described.
CORRELATIONS AND PATH ANALYSIS IN CASTOR (RICINUS COMMUNIS)
Authors: Bhatt Deepika , Reddy Tummala P.
Published: November 2014

Estimates of broad sense heritability, genotypic and phenotypic coefficients of variation, genetic advance, correlation coefficients, and path coefficient analysis were made on eight attributes of castor (Ricinus communis L.). Almost all characters showed high genotypic and phenotypic coefficients of variation. Heritability estimates ranged from 0.152 for bean yield/plant to 0.893 for number of nodes to primary raceme. High genetic advance was exhibited by the characters plant height (124.0) and days to flowering (37.8). High positive phenotypic correlations on bean yield/plant were shown by all characters except days to flowering and number of nodes to primary raceme. Path-coefficient analysis indicated that both the number of capsules/primary raceme (0.74) and the number of secondary branches (0.62) have large positive direct effects on bean yield/plant. These observations indicate that semi-dwarf lines with a larger number of capsules/primary raceme, and a moderate number of primary and secondary branches should be considered as parents for castor breeding programs.
THE INHERITANCE OF GOLDEN BODY, A SEX LINKED MUTANT IN THE MALARIA VECTOR ANOPHELES CULICIFACIES
Authors: Sakai R. K. , Baker R. H. , Dubash C. J.
Published: November 2014

Genetic analysis of a golden body mutant in Anopheles culicifacies Giles indicated that it is linked to the X chromosome. Linkage experiments with two other X-linked mutants indicated that the gene sequence was re-Vs-go and the observed recombination frequencies among them were as follows: re-Vs = 14.0%, Vs-go = 7.8% and re-go = 21.8%.
THE ANALYSIS OF MEIOSIS IN HYBRIDS. IV. PENTAPLOID HYBRIDS
Authors: Espinasse A. , Kimber G.
Published: November 2014

Models are developed which simulate expected chromosome pairing in pentaploid hybrids. Comparison of the various models with observed meiotic data allow the measurement of genomic affinity and therefore a new investigation of species and evolutionary relationships. The advantages and disadvantages of investigations at the pentaploid level are compared with those of the previously developed models for triploids and tetraploids.
ATTEMPTED GENE TRANSFER FROM TETRAPLOIDS TO DIPLOIDS INTRITICUM
Authors: Sharma H. C. , Waines J. G.
Published: November 2014

The possibility of introgression from tetraploid (2n = 28) AABB to diploid (2n = 14) AA wheats was investigated. Reciprocal crosses were made between tetraploid Triticum turgidum L. var. durum Desf. and diploids T. monococcum L. var. boeoticum Boiss., or T. urartu Tum.; and between T. turgidum var. carthlicum Nevski and T. monococcum L., or boeoticum, or urartu. The triploid F1hybrids were backcrossed to diploid parents. All backcross derivatives were lethal at BC1or BC2except those of durum × boeoticum which were carried to BC4. However, neither fertile plants nor plants with the diploid chromosome number were obtained up to BC4generation. As backcross generations advanced, backcross seed set, seed development, seed viability and plant vigor decreased. The failure of introgression from tetraploid to diploid wheats may be due to differential selection for unreduced gametes and adverse nucleo-cytoplasmic interactions.
THE RYE GENOME IN WINTER HEXAPLOID TRITICALES
Authors: Seal A. G. , Bennett M. D.
Published: November 2014

In eight winter triticales (× Triticosecale Wittmack) chosen from the Cambridge crossing program all seven rye (Secale cereale L.) chromosomes were present. However, a number of rye chromosomes showed an obvious reduction in the size of C-bands at one or more telomeres, compared with normal rye. In two lines the C-band at the short arm telomere of 2R was obviously larger than normal in rye. Comparison of these results with those published for spring triticales suggests that divergent selection pressures may determine the number and structure of rye chromosomes in winter and spring lines. In particular it is suggested that the differences may represent environmental adaptation and reflect selection pressure on the rye genome in triticale to conform to the cline for DNA amount per diploid genome on latitude previously described in cereal grain crops.
PANDRCONTROL OF FLAVONOIDS INBRONZECOLEOPTILES OF MAIZE
Authors: Styles E. Derek , Ceska Oldriska
Published: November 2014

Flavonols can accumulate in the coleoptiles of Zea mays as a function of either the P locus or the R locus. The P locus determines the accumulation of some 3-glucosylated flavonols and, in bz only, flavonol glycosides with the 3-hydroxyl free. The R locus determines the accumulation not only of the same flavonols, but also others that, in the coleoptile at least, appear R specific. Flavonol 3-glucosides can be produced in bz coleoptiles, presumably as a function of a second transferase enzyme, independent of Bz locus control, that has been reported previously by others. This second enzyme may be specific to flavonol glycosylation, and its activity can be quite high in some stocks.
ISOZYMES OF CULEX P. FATIGANS. III. GENETICS OF LEUCINE-AMINO-PEPTIDASE
Authors: Bhalla Satish C. , Narang Sudhir
Published: November 2014

Zymograms of leucine-amino-peptidases (LAP) of the mosquito Culex pipiens fatigans Wiedemann (C. p. quinquefasciatus) showed 20 isozyme bands in the fourth instar larvae, 13 in the pupae and 3 in the older adults. Homozygous strains of Lap-1F (Fast) and Lap-IS (Slow) were isolated and linkage studies carried out. Lap-1F and Lap-1S allozymes act as codominant alleles, are sex linked and are located in linkage group I. The gene sequence is e-M-mar-Lap-1 (eye-gap, sex, maroon-eye, leucine-amino-peptidase-1), and the linkage distances in the M-mar and mar-Lap-1 segments are 22.0 and 10.5, respectively. Gene frequency analysis of natural populations from Brazil and Pakistan showed the S allele was more frequent in the Brazilian populations whereas F was more frequent in the Pakistani populations. Fixation of F allele had occurred in two Pakistani populations.
THE CONTROL OF ALDEHYDE OXIDASE AND XANTHINE DEHYDROGENASE ACTIVITIES AND CRM LEVELS BY THEmalLOCUS INDROSOPHILA MELANOGASTER
Authors: Bentley M. M. , Williamson J. H.
Published: November 2014

The effects of five new mal alleles on aldehyde oxidase (AO) and xanthine dehydrogenase (XDH) activities and CRM levels in Drosophila melanogaster are described. These alleles were isolated by taking full advantage of the pleiotropic phenotype exhibited by all previously described mal alleles and represent at least three unique examples of mal function. At least one of these alleles is a representative of a new complementation group. Two other alleles exhibit a wild-type eye color in homozygous stock and one of these is "leaky", exhibiting some 50% of the XDH activity normally found in Oregon-R control flies and some 12% of the AO activity. CRM and activity levels have been quantitated for both enzymes in all allelic heterozygotes. XDH-CRM levels vary only slightly around wild-type levels while AO-CRM levels appear much more sensitive to mutational alterations.
THE EFFECT OF TELOMERIC HETEROCHROMATIN FROM SECALE CEREALE ON TRITICALE (X TRITICOSECALE). II. THE PRESENCE OR ABSENCE OF BLOCKS OF HETEROCHROMATIN IN ISOGENIC BACKGROUNDS
Authors: Bennett M. D. , Gustafson J. P.
Published: November 2014

The influence of telomeric heterochromatin blocks on early embryo and endosperm development, and on various agronomic parameters seen at maturity, was investigated using triticales (× Triticosecale Wittmack) isogenic for the presence or absence of the heterochromatin blocks on rye (Secale cereale L.) chromosomes 6R and 7R/4R. Absence of the telomeric heterochromatin blocks from the long arm of rye chromosome pair 7R/4R in DRIRA, and from the short arm of rye chromosome pair 6R in Rosner was significantly related with a lower production of aberrant endosperm nuclei and an increased kernel weight. The loss of the heterochromatin block on rye chromosome pair 7R/4R in DRIRA resulted in a significant yield increase, while there was no increase in yield when the heterochromatin block was missing from rye chromosome pair 6R in Rosner. The lack of yield increase in Rosner was apparently due to a significant decrease in fertility when the heterochromatin block on 6R was lost. The loss of the heterochromatin block on the short arm of rye chromosome 6R appears to have the same effect on aberrant endosperm nuclei production and kernel weight in two different genetic backgrounds. The rate of embryo and endosperm development showed a small but significant increase when the heterochromatin blocks were lost from both 6R and 7R/4R.
GENETIC VARIABILITY IN A HETEROGENEOUS POPULATION OF BARLEY (HORDEUM VULGARE)
Authors: Acharya S. N. , Jana S.
Published: November 2014

Two populations, dryland (D) and irrigated (I), were developed by propagating Composite Cross XXI (CCXXI) of barley (Hordeum vulgare L.) under contrasting soil moisture levels. Both populations were characterized by low outcrossing rates (less than 1%) and high levels of genetic variability. The means of these two populations did not show much divergence for six quantitative characters. However, substantially greater variability was observed in the D population for grain size and yield. Exposure to greater fluctuations of soil moisture and reduced intergenotype competition under dryland conditions were considered responsible for maintaining greater variability in the D population. The results indicated that continuous propagation of heterogeneous populations such as composite crosses of barley under low rainfall (average annual precipitation of about 350 mm) conditions is more effective in reducing genetic erosion and maintaining agriculturally useful variability than under more favorable rainfed conditions.
ANALYSIS OF THE RELATIONSHIP BETWEEN FLOWER COLOR AND DEGREE OF SIDE BRANCHING IN CROSSES BETWEEN FLAX GENOTYPES AND GENOTROPHS
Authors: Tyson Hugh , Fieldes Mary Ann
Published: November 2014

Side branching from the base of the main stem was examined in a diallel cross between flax genotypes and genotrophs. The flax genotrophs were produced by Durrant; the side branching in the diallel was studied in relation to segregation of flower color. The six parents were two linseed genotypes (highly branched), two fiber flax genotypes (sparsely branched), and the L and S genotrophs induced within the flax genotype Stormont Cirrus by one generation of NPK or NK treatment, respectively. L resembled linseed genotypes, which have been selected for seed production and characteristically have profuse basal branching. In contrast, S resembled fiber flaxes selected for tall, unbranched stems. One of the flax genotypes (Mandarin = M) carried a recessive flower color gene (mauve); the remaining five parents were all blue flowered. Crosses segregated in the F2for blue versus mauve. In the F2progeny of crosses with parent M and a linseed parent, blue flowered segregants had more side branching than corresponding mauve flowered segregants. In contrast, when the other parent crossed with M was a fiber flax, blue flowered segregants had less side branching than mauves. L behaved like the linseed parents and S like the fiber flax parents in this respect. Causes of the apparent association between the flower color loci and loci involved with side branching are discussed.
SIGNIFICANCE OF PLANT METABOLISM IN THE MUTAGENICITY AND TOXICITY OF PESTICIDES
Authors: Wildeman Alan G. , Nazar Ross N.
Published: November 2014

In an attempt to gain an overall estimate for the influence of plant metabolism on environmental mutagenesis, the mutagenicity of an assortment of agricultural pesticide preparations in the Salmonella bio-assay was evaluated using both rat liver S9 and plant enzyme homogenates as activating systems. The study indicates that plant metabolism can alter the results of this short-term mutagenicity test: some compounds which are non mutagenic in the Salmonella bio-assay (e.g. diquat) give positive responses, some preparations such as captan become more or less mutagenic, and some, such as triallate, become significantly more toxic to the tester strains. Furthermore, dose response curves suggest that even when both plant homogenates and rat liver S9 supernatant activate a compound, the mutagens which are formed may differ. Five-day old alfalfa (Medicago sativa L.), corn (Zea mays L. var. Golden Jubilee), bean (Vicia faba L.), pea (Pisum sativum L. var. Laxton's Progress), sunflower (Helianthus annuus var. Krasnodarets), tobacco (Nicotiana tabaccum L. var. Wisconsin 58), and wheat (Triticum aestivum L.) were tested and compared as activating systems; these were prepared by an assortment of cell disruption techniques including blending, homogenizing, sonication, and high pressure disruption methods. For routine testing, filter sterilized, blended, S14 supernatants of corn or wheat were the most promising. No correlation was observed between levels of activation by the various plant species and their protein contents, catalase, or peroxidase activities. The preparations, however, could be standardized using specific chemical compounds in the bio-assay.