bluuebunny/crossref_metadata_2025 huggingface dataset:
THE INTERRELATIONSHIP OF GENETIC AND MATERNAL CONTROL IN A SELECTED POPULATION OF LOLIUM PERENNE
Authors: Hayward M. D. , Lawrence T.
Published: November 2014

The interrelationship of the maternal and genetic control for seed weight, rate of tiller production, length of fifth leaf, and total adult plant production in a 5 × 5 diallel cross of Lolium perenne L. were studied by estimation of the phenotypic, environmental, genetic, and maternal correlations. Genetic and maternal components of increased seed size lead to a reduction in tillering, leaf size and final production indicating that large seeds are not generally advantageous to growth and development. Environmental factors which promoted tillering also increased leaf length. Maternal control showed a similar pattern. However, genetic control indicated that the faster the tillering, the shorter the leaves, thus emphasizing the possible danger of considering only a single factor in selecting for increased yield. Phenotypic correlations indicate that total production was determined largely by tiller production with environmental factors influencing leaf length and tiller production. Neither genetic nor maternal control of tiller number or leaf size at the seedling stage greatly influenced final production, indicating that selection for either of these characters separately would not likely influence yield. The controls for maternal and additive genetic effects were found to be different. Maternal effects were strong and extended well beyond the influence of seed size effects.
THE EFFECT OF TEMPERATURE ON MEIOSIS AND POLLEN DEVELOPMENT IN WHEAT AND RYE
Authors: Bennett M. D. , Smith J. B. , Kemble R.
Published: November 2014

The durations of meiosis and pollen development were estimated in Petkus Spring rye and Chinese Spring wheat grown at 15, 20 and 25 °C. Over the range 15-25 °C, meiotic duration and pollen maturation time decreased with increasing temperature and the ratio between the durations of these stages at 25 °C and at 15 °C (Q10) indicated that the temperature responses of meiotic and pollen development were similar in both species. Both within and between species meiosis and pollen maturation had constant relative durations at each temperature. The effect of low temperature on the duration of meiosis and pollen development was similar in Holdfast, an extreme type of winter wheat, as in Chinese Spring. The relevance of these results to hybrid cereal breeding are mentioned. In plants grown at 25 °C, abnormal meiotic and pollen development resulting in male sterility was seen in some anthers. The cause of male sterility appeared to be thickening of tapetal cell walls concurrent with abnormal late meiotic development in PMC's.
AVENA DAMASCENA: A NEW DIPLOID OAT SPECIES
Authors: Rajhathy Tibor , Baum B. R.
Published: November 2014

A new diploid species of oat from Syria, named Avena damascena Rajhathy et Baum, is described. It has some macro- and micromorphological similarities to A. wiestii and A. prostrata, both diploids, and to tetraploid A. barbata. It differs from one or the other of them in its lemma tips, lodicules, epiblast and in the unique structure of the cuticle on the glumes. Avena damascena has a distinct symmetrical karyotype, designated Ad. The karyotype of A. prostrata is designated Ap. Avena damascena is isolated from A. prostrata by hybrid sterility and from the other diploids by cross-incompatibility. Avena damascena and A. prostrata are considered relicts of a common population because they retain a high degree of genome homology. Their chromosomes differ by two interdependent interchange complexes which led to a pollen sterility. Genome relationships in the A genome group of diploids are briefly discussed in terms of meiotic pairing patterns and karyotypes.
THE EFFECT OF ADENOSINE TRIPHOSPHATE ON MITOMYCIN C-INDUCED ABERRATION YIELD INVICIA FABA
Authors: Bempong Maxwell A. , Newsome Yvonne L.
Published: November 2014

The effect of adenosine triphosphate (ATP) on the yield of mitomycin C-induced chromosome aberrations was examined with the root meristematic cells of Vicia faba. ATP content of root tips, as determined by luciferin-luciferinase assay, increased by over twofold after treatment in an ATP solution. The results indicated that ATP, given as a pre- or post-treatment, reduced the aberration yield. The equal efficacy of both pre- and post-ATP treatment in the modification of aberration yield may suggest a significant biochemical role played by ATP during the recovery period. The suggestion is further made that ATP serves as an energy source for a metabolic process which regulates repair of damaged chromosomes.
AN EXAMINATION OF CHROMOSOMAL INDICES
Authors: Filion W. Gary
Published: November 2014

Equations relating the effects of an increment and a decrement of a chromosome arm on arm ratio, centromeric index and morphological index were derived. These equations demonstrate that an increment and decrement of the same magnitude alter specific indices by differing amounts. Further, the equations for centromeric index and morphological index with one exception were chromosome dependent. The use of these indices in applied cytogenetics may require reconsideration.
THE GENETIC BASIS FOR THE DIFFERENCE IN SEED WEIGHT BETWEEN THATCHER AND SELKIRK WHEATS
Authors: Talukdar B. S.
Published: November 2014

The inbred backcross line method was used to study the genetics of the difference in seed weight between two hard red spring wheat cultivars, Thatcher and Selkirk. Three major genes, one with large and two with relatively small but equal effects, were found to control the difference. The distribution of the alleles was unidirectional with Thatcher carrying the alleles for light and Selkirk carrying the alleles for heavy seed. Linkage, dominance, and epistasis caused practically no bias in the analysis. The result indicates that breeding for seed weight should be simple.
ETHIDIUM BROMIDE RESISTANCE AND PETITE INDUCTION IN SACCHAROMYCES CEREVISIAE
Authors: Bech-Hansen N. T. , Rank G. H.
Published: November 2014

Six ethidium bromide (EB) resistant mutants were isolated and characterized. The resistance in three isolates was stable, nuclearly inherited and sensitive to glucose repression. Unstable EB dependent resistance was present in the other isolates. The mutants with stable and one of those with unstable EB resistance showed cross resistance to the cationic detergent, cetyltrimethylammonium bromide. Both anaerobiosis and oligomycin inhibited EB induction of petites in the EB sensitive strain and in the EB-sensitized resistant strains. The observations are discussed in relationship to a mechanism of EB resistance and petite induction at the level of the mitochondrial membrane.
TWO CYTOPLASMICALLY INHERITED CHLORAMPHENICOL RESISTANCE LOCI IN YEAST (SACCHAROMYCES CEREVISIAE)
Authors: Kleese R. A. , Grotbeck R. C. , Snyder J. R.
Published: November 2014

Cytoplasmically inherited chloramphenicol resistant mutants were tested for allelism and found to be non-allelic. The loci appear linked but it has not yet been possible to obtain a good estimate of the amount of linkage.
THE SIGNIFICANCE OF MEIOTIC CHROMOSOME PAIRING IN TETRAPLOID (2n = 28) BROMUS PUMPELLIANUS SCRIBN. SSP. DICKSONII
Authors: Armstrong K. C.
Published: November 2014

Bivalent formation was predominant at meiosis in B. pumpellianus ssp. dicksonii. The average in 15 plants ranged from 11.38 to 13.77 bivalents per cell. The high chiasma frequency (23.41-26.74) was a reflection of the high frequency of ring bivalents (9.48-12.42). A low frequency of quadrivalents occurred (0.06-1.22). A karyotype of this species was presented from both a highly contracted and moderately contracted cell and the differences between these two were noted. Four satellites were found, two large and two minute. There were 3-5 submedian and 5-7 median chromosomes depending on the cell studied. In addition two subterminal chromosomes were present. The meiotic and karyotype analysis suggest a deviation from an autotetraploid behaviour, but the presence of quadrivalents and similarities between pairs in the karyotype suggested closely related genomes. Alternatively it was considered that the quadrivalents could be due to translocation heterozygotes. The implications of these results were discussed in relation to the reported meiotic events in the octoploids, B. inermis and B. pumpellianus.
INCREASED FREQUENCY OF AUXOTROPHIC MUTANTS OF USTILAGO HORDEI AFTER COMBINED UV IRRADIATION AND INOSITOL STARVATION
Authors: Thomas P. L.
Published: November 2014

Auxotrophic mutants of Ustilago hordei were recovered after UV irradiation of a wild-type culture, inositol starvation of an inositol-requiring culture and a combination of the two methods. 1.9% of the survivors of UV irradiation followed by inositol starvation were found to carry a requirement additional to inositol. Inositol starvation by itself gave only 0.27% recovery while UV irradiation alone was even less efficient.
THE EFFECT OF IONS ON THE STRUCTURE AND FUNCTION OF FACULTATIVE HETEROCHROMATIN IN THE MEALY BUG
Authors: Pallotta Dominick
Published: November 2014

When mealy bug testis cells are placed in an isotonic salt solution, a large mass of heterochromatic chromosomes is visible. As the ionic strength is lowered, these chromosomes decondense and can no longer be distinguished from the euchromatic chromosomes. This change is reversed by returning the cells to isotonic medium. Labeling experiments showed that this recondensation process is specific in the sense that it is the original heterochromatic chromosomes which recondense. In isotonic salt solutions, the heterochromatic chromosomes synthesize little or no RNA as compared to the euchromatic chromosomes. In hypotonic solution, cells show a general decrease in RNA synthesis, but they exhibit the same pattern of RNA synthesis as cells in isotonic solution. Therefore, it is concluded that this ion-mediated decondensation of chromosomes does not increase their capacity to synthesize RNA.
EFFECT OF POPULATION DENSITY ON THE SPECIFIC ACTIVITY OF VARIOUS ACID HYDROLASES IN HUMAN SKIN FIBROBLAST MONOLAYERS
Authors: Shanfield Bernice , Pinsky Leonard
Published: November 2014

The specific activity of β-D-galactosidase, α-L-fucosidase, β-D-N-acetyl-galactosaminidase, and acid phosphatase have been measured as a function of cell density in human skin fibroblast monolayer cultures. Over a fivefold range of cell density, extracts of cells at the highest density had 2.5-fold as much specific activity of the three acid glycosidases as those at the lowest density. In contrast, the concomitant increase of acid phosphatase activity was only 0.5-fold. These results are in accord, qualitatively, with two previous studies. In the present study, the acquisition of specific acid glycosidase activity was related linearly to increasing cell density; in the preceding ones the rise of specific enzyme activity began several days after subculture. It is suggested that one source of this disparity is a difference in experimental design. In the present study, flasks with various cell densities were harvested at the same time; in the former studies, flasks initially innoculated with the same number of cells were harvested at progressively longer times after subculture. The latter protocol permits a disproportionate influence of "subculture shock" on cells in the flasks with relatively low cell densities.
GENETIC CONTROL OF AGGRESSIVENESS IN USTILAGO HORDEI. I. NATURAL VARIABILITY AMONG PHYSIOLOGICAL RACES
Authors: Emara Y. A.
Published: November 2014

A biometrical genetic study was carried out to investigate the natural variability in aggressiveness (degree of virulence) among the 13 races of U. hordei using monosporidial cultures isolated at random to set up all possible combinations among the races. Barley plants of the variety Odessa were used as host in a completely randomized blocks experiment where aggressiveness was recorded as percentage of infected spikes in a row of 30 plants.A considerable amount of variability was detected, race No. 1 being the most and race No. 5 the least in aggressiveness. Genetic variability amounted to 51.23% of the total phenotypic variability. It was obvious that most of the genetic variability was due to additive genetic effects, suggesting no important role of dominance and epistasis. The practical application of the findings in developing resistant varieties of plants is discussed.
CELLULAR DISTRIBUTION AND POSSIBLE MECHANISM OF SEX-DIFFERENTIATION IN XX/XY CHIMERIC MICE
Authors: Milet Rene G. , Mukherjee Barid B. , Whitten Wesley K.
Published: November 2014

Anatomical, histological and karyological analyses on various somatic tissues from four artificially assembled XX/XY mouse chimeras were carried out in an attempt to determine the possible mechanism of sex differentiation in sex-chromosome chimeric mice. The data obtained from the present experiment suggest that genetic sex of various body cells has no bearing on the host's phenotypic sex, at least in mice. The analysis of the experimental data available in the literature and from the present experiment allowed the authors to postulate a possible mechanism for sex-determination in mammals. According to this model, the male- and female-determining factors of the sex chromosomes do not assert their influences on gonadal differentiation through either the somatic or the germinal elements of the primordial gonads alone. Rather there is an interaction of the sex constitution of both cell types; that is, the primordial germ cells and the blastema cells of the gonadal ridges play complementary roles in gonadal differentiation, and the final composition of the gonad is determined by thresholds of these factors.
USE OF MONOTELOTRISOMICS FOR LINKAGE MAPPING IN BARLEY
Authors: Fedak George , Tsuchiya T. , Helgason S. B.
Published: November 2014

Analysis of bulk F2 progenies from monotelotrisomic hybrids for two known genes fc and br showed that the gene-centromere distance and frequency of homozygous recessive F2 segregates were inversely related. Based on this relationship the new genes sb, ea, gs3, f5 were assigned to positions on chromosome 1 relative to the previously mapped genes. The centromere position on chromosome 1 was located between the markers rs and n. Two previously undescribed recessive mutants, revoluted leaf (rvl) and Parkland spot (sp,,b), were associated with the long arm of chromosome 5 through the use of monotelotrisomic 14 + 5L.
CORRELATED RESPONSE TO NATURAL SELECTION IN LABORATORY POPULATIONS OFTRIBOLIUM CASTANEUM
Authors: Soliman M. Hani
Published: November 2014

Intra- and interpopulation correlations between productivity and period of productivity were significant. One-day-old pupae and one-day-old adult weights were not associated with productivity. The intrapopulation correlation coefficients between productivity and developmental time were found to be significant. However, all of them (except one) were negative. Significant interpopulation relationships were noted when productivity was correlated with 13-day larval weight and with developmental time. Positive and negative correlations were found between productivity-larval weight and productivity-developmental time, respectively. It is concluded that developmental time is the most important factor in controlling productivity in T. castaneum under the constant conditions of the present investigation.
SEX-LINKED TRANSLOCATIONS, SEMISTERILITY AND LINKAGE ALTERATIONS IN THE MOSQUITOAEDES AEGYPTI
Authors: Bhalla Satish C.
Published: November 2014

Seven sex-linked translocations were artificially induced and isolated in the mosquito Aedes aegypti. All translocations have passed through four generations. Each translocation heterozygote shows characteristic sterility with small variation. Egg hatches of the seven translocation heterozygotes ranged from 18% – 71%. Two translocations are TMtype, i.e. linked to the M chromosome, and the remaining five are Tmtype, i.e. linked to the m chromosome. Possibilities of using both types of translocation for genetic manipulation of field population are discussed. The three linkage groups (I,II,III) have been correlated to the three pairs of chromosomes (1, 2, and 3). For the first time in mosquitoes, translocations have been utilized to correlate a specific gene to a particular segment of a chromosome. The blt locus has been assigned to the small terminal segment distal to the secondary constriction on chromosome 3.
SPECIES RELATIONSHIPS IN THE LOTUS CORNICULATUS GROUP AS DETERMINED BY KARYOTYPE AND CYTOPHOTOMETRIC ANALYSES
Authors: Cheng Rosa I-Jung , Grant W. F.
Published: November 2014

An analysis was made of chromosome morphology and, by Feulgen cytophotometric measurements, of the nuclear deoxyribonucleic acid (DNA) content of L. corniculatus and related diploid species of the L. corniculatus group (L. alpinus, L. borbasii, L. corniculatus var. brachyodon, L. filicaulis, L. japonicus, L. krylovii, L. pedunculatus, L. schoelleri, L. tenuis) and L. coimbrensis of the L. aegeus group. The idiogram of L. coimbrensis differed markedly from those for the species of the L. corniculatus group, which were considerably more uniform. Lotus pedunculatus was the only species with chromosomes bearing satellites. Since L. corniculatus has a somatic chromosome number of 24, compared to L. corniculatus var. brachyodon with 12, the latter represents a new diploid taxon which should receive further taxonomic study. DNA values differed between the species, and in general, total complement lengths were correlated with DNA values. It is suggested that classical karyotype analysis may not be a suitable method to investigate the parentage of the tetraploid, L. corniculatus, because of chromosomal repatterning which has occurred during the evolutionary development of the closely related diploid species.
CHROMOSOME EVOLUTION: REPETITIVE EUCHROMATIC CHROMOSOMAL SEGMENTS IN HAWAIIANDROSOPHILA
Authors: Yoon Jong Sik , Wheeler Marshall R.
Published: November 2014

We have found five distinct chromosomal regions which are repeated within the genomes of 11 endemic Hawaiian Drosophila species. One of the duplications was observed in more than 130 species (of three genera) of Hawaiian Drosophilidae. These "repeats" show synapsis in some nuclei, not in others; repeated segments are sometimes tandem while others are separated on their respective chromosomes. From these observations, one can speculate that chromosomal rearrangements produced by unequal crossing over due to such "repeats," and the possible development of new or modified gene action may provide, at least in part, an explanation of the remarkably rapid evolution and speciation in Hawaiian Drosophila.
GENOTYPE × YEAR INTERACTIONS AND ECOVALENCE IN RASPBERRY SELECTION
Authors: Fejer S. O.
Published: November 2014

There was a significant negative correlation between yields of a collection of raspberry plants in seven consecutive years and their ecovalence values. An exceptional plant, ranking high in both yield and ecovalence, was selected and named Festival (Fejer and Spangelo, 1971). Low growth rate and cold resistance seem to be the factors responsible for its high adaptability.
CHROMOSOMES OF RHAGIONIDAE, STRATIOMYIDAE AND XYLOMYIDAE (DIPTERA)
Authors: Boyes J. W.
Published: November 2014

The chromosome complements of 22 species of Stratiomyidae, 1 of Rhagionidae and 1 of Xylomyidae are described. Chromosome numbers range from 2n = 8 to 16 with 16 as the most common number and presumably the primitive number. The 56 chromosome complements averaged 55.2 μ, in TCL which seems to increase with increasing number of chromosomes. The similarity of the Stratiomyidae and the Tabanidae regarding chromosome numbers and range is noted.
INHERITANCE AND ALLELIC RELATIONSHIPS OF SEVEN CHLOROPHYLL-DEFICIENT MUTANTS IN BRASSICA CAMPESTRIS L.
Authors: Stringam Gary R.
Published: November 2014

Genetic data on seven chlorophyll-deficient mutants showed that all were independent monogenically-controlled recessive genes. The symbol yg is proposed for these characters with the designation yg-1 to yg-7. The value of these mutants in genetic research and in practical plant breeding problems is discussed.
THE CHROMOSOME COMPLEMENT OF THE NARWHAL (Monodon monoceros)
Authors: Andrews J. C. , Dill F. J. , Masui S. , Fisher H. D.
Published: November 2014

The karyotype of a male narwhal (Monodon monoceros) is described. The chromosome number was found to be 2n = 44. The karyotype is similar to all other whale species reported except that of the sperm whale (Physeter catodon), and the killer whale (Orcinus orca).The findings presented here add further support to the concept that the whales may be monophyletic in origin.
SENSITIVITY OF THE MOUSE OOCYTES TO THE INDUCTION OF TRANSLOCATIONS BY IONIZING RADIATIONS
Authors: Gilliavod N. , Leonard A.
Published: November 2014

Female mice from the C57B1 strain received 0, 50 or 200 R whole body X-irradiation and were mated to control males from the same strain. Using an air-drying technique, the testes of their F1males were analysed for the presence of chromosome rearrangements, but no translocation congurations were observed in the dividing spermatocytes of the 100 control males and of the 185 F1sons from irradiated females.Since meiotic preparations made one day after exposure of the females to X-irradiation showed the presence of chromosome rearrangements in some first meiotic metaphases, it could be inferred that the absence of translocated offspring after maternal X-ray exposure probably resulted from germinal selection.
A SIMPLE AND EFFICIENT SQUASH TECHNIQUE FOR SOMATIC CHROMOSOMES OF CRUCIFERS
Authors: Satyanarayana A. , Sen S. K.
Published: November 2014

A simple squash technique has been proposed to study the somatic chromosomes of crucifers. Essentially the technique consists of pretreatment with alpha-bromonaphthelene followed by fixation in methanol, acetic acid (1:1) and Newcomer's fluid, and staining with aceto-orcein. Consistent and excellent preparations have been obtained in rapeseed, cabbage, cauliflower, radish, turnip and Iberis spp.
SOMATIC ASSOCIATION OF BOVINE X CHROMOSOMES
Authors: Antunes-Correia J. C. , Nunes-Madeira J. C.
Published: November 2014

Preliminary results of a study of the somatic association of the X chromosomes of the cow show that they were closer on the metaphase plate than expected by chance. This lends support to the suggestion that X chromosomes association is a generalized phenomenon in mammalian females.
THE CYTOGENETIC POSITION OF AVENA PROSTRATA AMONG THE DIPLOID OATS
Authors: Ladizinsky Gideon
Published: November 2014

The chromosome architecture of the newly discovered diploid oat A. prostrata is similar to that of A. longiglumis. The hybrids involving these oats had many PMC's with seven bivalents and were partially fertile. Considerable restoration of fertility in the F2 was coupled with improvement of chromosome pairing and usually linked to the diagnostic morphological characters of either parent. The hybrids involving A. prostrata and A. strigosa were characterized by multivalent associations in meiosis, indicating at least five translocation differences between the two species. By combining the cytogenetical, morphological and the ecological evidence, it was suggested that A. prostrata is either the first evolutionary step from A. longiglumis toward A. damascena and A. strigosa or, more probably, the common ancestor of these three diploid oats.
CHROMOSOMAL POLYMORPHISM COMMON TO SEVERAL SPECIES OFJUNCO(AVES)
Authors: Shields Gerald F.
Published: November 2014

Karyotypes were obtained from primary kidney cultures of nearly 250 individuals belonging to six nominate species of the avian genus Junco. Chromosome 2 was found to be dimorphic in four of the six species and chromosome 5 was dimorphic in five of the six species. The dimorphism appears to be due to the presence of a pericentric inversion in each of these autosomes. It is hypothesized that chromosomes 2 and 5 are ancestral and gave rise to chromosomes 2smand 5mrespectively. The sample of the slate-colored junco, Junco hyemalis, the largest studied, conforms to the Hardy-Weinberg equilibrium and suggests that a random sample was drawn from a randomly mating population.
EFFECT OF INCUBATION PERIOD ON THE RATE OF MITOTIC DIVISION OF IN VITRO LEUCOCYTE CULTURES OF 18 STRAINS OF MICE
Authors: Ray M.
Published: November 2014

Leucocytes of 18 strains of mice were cultured according to the method described previously with culture incubation periods of 48 hr, 72 hr and 96 hr. Many well spread metaphase plates, suitable for karyotype analysis, were obtained. Different incubation periods were required by the different mouse strains in order to obtain the highest possible number of mitotic divisions.
INTERACTION OF DAUNOMYCIN WITH MEIOTIC CHROMOSOMES IN VICIA FABA
Authors: Bempong Maxwell A.
Published: November 2014

Daunomycin interferes with the meiotic cycle and structural integrity of chromosmes if administered to microsporocytes of Vicia faba during the meiotic prophase substages prior to diplotene. The principal cytological consequences of daunomycin treatment are as follows: induced achromatic lesions, chromosome fragmentation, terminal and interstitial deletions, loose or non-pairing regions, multivalent associations, reduced chromosome condensation, chromosome stickiness, dicentric and side-arm bridges and chromatid loops. A correlation between inhibition of DNA or RNA and the cytological manifestation of structural anomalies or unfolding of meiotic events is discussed.
A COMPARISON OF CELL SURVIVAL AND CHROMOSOMAL DAMAGE USING CHO CELLS SYNCHRONIZED WITH AND WITHOUT COLCEMID
Authors: Bhambhani R. , Kuspira J. , Giblak R. E.
Published: November 2014

Chinese hamster ovary (CHO) cells, synchronized in mitosis either by mechanical shaking or by chemical arrest with Colcemid, were X-irradiated at different times in the cell cycle and examined for both cell survival (ability to form colonies) and chromosomal damage. The investigation revealed that the two radiation responses were "age-dependent", viz., the proliferative ability of cells to form colonies was dependent upon the cyclic phase in which the cells were irradiated. Similarly, the extent of chromosomal damage and the types of radiation-induced chromosomal aberrations were also dependent upon the cyclic stage of the cells during irradiation. Cells synchronized by the aforementioned methods essentially gave the same results as borne out by statistical analysis despite the apparent indication that cells synchronized with Colcemid revealed a slight overall increase in radiation-induced chromosomal damage for all four cyclic phases. It was observed that cells irradiated in mitosis were most radiosensitive while cells irradiated during the DNA synthetic period were most resistant. A positive correlation between cell survival and chromosomal damage was observed which lends support to the theory that radiation-induced damage to chromosomes is primarily responsible for the loss of proliferative ability. However, the possibility that radiation-induced damage may be incurred by other cellular organelles, and this may to some degree be responsible for the loss of reproductive integrity, cannot totally be overlooked.
STUDIES ON THE CYTOGENETIC AND GENETIC EFFECTS OF FLUORIDE ON BARLEY.: I. A COMPARATIVE STUDY OF THE EFFECTS OF SODIUM FLUORIDE AND HYDROFLUORIC ACID ON SEEDLING ROOT TIPS
Authors: Bale S. S. , Hart G. E.
Published: November 2014

The effects of sodium fluoride and hydrofluoric acid on barley were determined and compared following treatments of seedling root tips at three different concentrations (1 × 10−2M, 1 × 10−4M, 1 × 10−6M) and for six different durations (12, 24, 36, 48, 60, and 72 hr). Treatment with a 1 × 10−2M concentration of either sodium fluoride or hydrofluoric acid markedly slowed the rate of seedling growth. However, no inhibition of growth was observed following treatment with a 1 × −4M or a 1 × 10−6M concentration of either agent. Chromosomal aberrations were induced and mitosis was inhibited by each of the three different concentrations of both sodium fluoride and hydrofluoric acid. The sodium fluoride treatments induced a higher frequency of chromosomal aberrations than did the hydrofluoric acid treatments, possibly due to differences in pH and in the total available fluoride ions. These treatments produced bridges, fragments, chromosome gaps, binucleate cells and micronuclei.
A CYTOLOGICAL SURVEY OFZEA-TRIPSACUMHYBRIDS
Authors: Newell C. A. , Wet J. M. J. de
Published: November 2014

Reciprocal crosses involving various combinations of diploid (2n = 20) and tetraploid (2n = 40) Zea mays L. (maize), diploid (2n = 20) Zea mexicana (Schrad.) Kuntze (annual teosinte), and tetraploid (2n = 40) Zea perennis (Hitchc.) Reeves and Mangelsdorf (perennial teosinte) were studied cytologically. Observations of chromosome behavior during meiosis indicated that chromosomes of Z. perennis were more compatible with those of Zea mays than with those of Z. mexicana. Hybrids between Z. mays and diploid (2n = 36) or tetraploid (2n = 72) Tripsacum dactyloides (L.) L, incorporating different numbers of genomes from each parent and ranging in chromosome number from 2n = 28 28 to 2n = 82, were also examined at meiosis. Allodiploids (2n = 28) combining one Zea genome with one Tripsacum genome showed a low level of synaptic bivalent formation, indicating limited chromosomal homology between the two genera. Almost without exception, maize-Tripsacum hybrids exhibited more chromosomal association than expected on the basis of strictly homologous pairing; however, only a few plants possessed configurations stable enough to be taken as evidence of possible intergeneric segmental exchange. Triple hybrids involving maize, teosinte, and Tripsacum were produced in several combinations by pollinating maize-Tripsacum hybrids with annual or perennial teosinte. These showed chromosomal associations in accordance with the expected, on the basis of cytological data from maize-Tripsacum and maize-teosinte hybrids. These cytological observations suggest that teosinte and maize are conspecific, and that teosinte could not have originated as a by-product of Zea-Tripsacum introgression.
COMPLEMENTARY GENIC COMPLEX FOR ANTHOCYANIN PIGMENTATION IN THE APICULUS OF RICE (ORYZA SATIV AL.)
Authors: Setty M. V. N. , Misro B.
Published: November 2014

The C-A-P genie complex for anthocyanin pigmentation in the apiculus of japonica rice has been recently found to be also applicable to indica rice. The present investigation reveals a considerable difference in the nature and the number of localization genes. Accordingly, the complementary genie complex for anthocyanin pigmentation in the apiculus of both japonica and indica rices is C-A-PaPbor C-A-PaPcor C-A-PbPc. Any two of the localization genes (Pa, Pb, Pc,) together also act as basic genes for other localization genes governing anthocyanin pigmentation in all other parts of the plant.
THE ULTRASTRUCTURE OF KINETOCHORES OF UNPAIRED CHROMOSOMES IN A WHEAT HYBRID
Authors: Wagenaar E. B. , Bray D. F.
Published: November 2014

The kinetochore region of unpaired chromosomes (univalents) consists of two kinetochores, each belonging to a sister chromatid, that are located adjacent to one another on the surface of the univalent chromosome. This condition results in a movement by the univalent towards one of the polar regions at the onset of metaphase I. Once arrived in this region, one of the sister kinetochores obtains attachments of microtubules from the opposite pole. This results in a gradual return of the univalent to the equatorial plate, where it reaches an equilibrium. The sister kinetochores remain adjacent during the movement, but once arrived at the metaphase plate they develop a typical mitotic appearance, in which the sister kinetochores have opposite positions on the chromosomes.
THE LOCATION OF A RECESSIVE GENE FOR CHLOROPHYLL DEFICIENCY IN DIPLOIDSOLANUM TUBEROSUMBY MEANS OF TRISOMIC ANALYSIS
Authors: Hermsen J. G. Th. , Ramanna M. S. , Vogel J.
Published: November 2014

A light green monogenic recessive mutant was found in diploid Solanum tuberosum. The mutant gene (v) was located by aneuploid analysis on the extra chromosome of a trisomic (2n = 25) derived parthenogenetically from cv. Intenso (2n = 48). The extra chromosome was identified at pachytene stage as chromosome XII according to the numbering system of Yeh and Peloquin (1965). The mutant gene appeared to be genetically independent of the linkage group B-I-F-Ow for anthocyanin distribution and of the gene P for anthocyanin production.
CONSTITUTIVE HETEROCHROMATIN G-BANDS AND ROBERTSONIAN REARRANGEMENTS IN THE CHROMOSOMES OF AKODON MOLINAE (RODENTIA: CRICETIDAE)
Authors: Bianchi N. O. , Vidal-Rioja Lidia , Bianchi Martha S.
Published: November 2014

The cytogenetic study of a population of A. molinae showed individuals with 2n = 42 chromosomes including a large metacentric pair (chromosome 1); individuals with 43 chromosomes having one chromosome 1 and two large sub-terminal elements (chromosomes 1a and 1b), homologues of the long and short arms of the chromosome 1, respectively; and animals with 44 chromosomes having a pair of 1a and a pair of 1b chromosomes. The analysis of chromosome length combined with g- and c-bands indicate that there are only two probable mechanisms of chromosome rearrangement explaining the pair 1 polymorphism. In the first process it is assumed that chromosome 1 arose by centric fusion of two acrocentric chromosomes following pericentric inversions of the short arms of chromosomes 1a and 1b. The data given by c-bands indicate that this hypothesis should be complemented by deletions of the centromeric heterochromatin of 1a and 1b chromosomes. The second mechanism suggests that chromosomes 1a and 1b appear via a centromeric breakage of chromosome 1 followed by pericentric inversions. The blocks of c-heterochromatin in chromosomes 1a and 1b are explained by a process of saltatory replication.
DECREASE IN CHROMOSOMAL DNA CONTENT AT HIGHER POLYPLOIDY LEVEL IN VICIA FABA ROOT MERISTEMS
Authors: Deka P. C. , Sen S. K.
Published: November 2014

The DNA content of the nucleus is expected to increase proportionately with the increase of ploidy. Estimation of the DNA content of the endopolyploid root meristem nuclei of Vicia faba has been done through cytophotometry from 2n to 16n level. Observations indicate that a decline in nuclear DNA content takes place at higher ploidy level while the overall karyological integrity of the chromosomes and their number are apparently maintained as normal.
THE INHERITANCE OF PIGMENTATION IN CERTAIN PLANT PARTS OF RICE
Authors: Dhulappanavar C. V.
Published: November 2014

Four genes were indicated for ligule colour, whereas digenic segregation was obtained for pigmentation in glume, leaf-apex-margin and midrib. Linkage between a basic-complementary gene for ligule colour (Plg) and one of the complementary genes specific for pigmentation in midrib (Plm), glume (Pg) and leaf-apex-margin (Pla) is established. This linkage group (Plg-Plm-Pg-Pla) forms part of linkage group II of Misro et al. (1966). The genes Pla and Plg are recommended for inclusion in that group.
IN VITRO EMBRYOGENESIS: AN EXPERIMENTAL MODEL FOR THE UNDERSTANDING OF REPRODUCTIVE PHYSIOLOGY AND DEVELOPMENT IN MAMMALS
Authors: Mukherjee Anil B.
Published: November 2014

A complete in vitro technique has been developed in the mouse for capacitation of epididymal spermatozoa, maturation of ovarian oocytes and fertilization of such gemetes to give rise to viable embryos, which, when transplanted to proper recipients result in normal, fertile progeny. This technique, although it requires perfection, has many future possibilities and potential applications as a research tool in solving problems of mammalian reproductive physiology and developmental biology. It may be useful in the investigation of (a) gene action in the X chromosome and initiation of X-inactivation during embryogenesis; (b) nuclear transplantation and the ontogenetic commitment of oocyte cytoplasm; (c) the role of drugs, mutagens and carcinogens in the fetal environment; (d) genetic engineering; eg. enzyme induction and (e) many problems involving fertility and sterility.
CYTOGENETIC RELATIONSHIPS BETWEEN THE DIPLOID OAT A. PROSTRATA AND THE TETRAPLOIDS A. BARBATA, A. MAGNA AND A. MURPHYI
Authors: Ladizinsky G.
Published: November 2014

The diploid oat Avena prostrata and the tetraploid A. barbata share the same general morphological characteristics which are also found in the diploid A. strigosa. Chromosome pairing and fertility of the triploid hybrids involving A. barbata and the two diploids suggest that A. prostrata is not as related to A. barbata as A. strigosa and most probably did not participate in the formation of this tetraploid. This conclusion is also supported by the number of the satellited chromosomes in the three oat species and their hybrids and by chromosome pairing in the hybrid involving A. strigosa × A. prostrata amphidiploid and A. barbata. It is speculated that the tetraploid A. barbata had evolved from A. strigosa and another yet undiscovered strigosa-like diploid oat. Some cytological attributes of this hypothetical diploid are suggested. Morphologically and cytologically A. prostrata is unrelated to the tetraploids A. magna and A. murphyi.
HOMOLOGY BETWEEN THE A AND B GENOMES OF BROMUS PUMPELLIANUS SSP. DICKSONII
Authors: Armstrong K. C.
Published: November 2014

Chromosome pairing in the tetraploid F1 hybrid (AAAB) from B. erectus (AAAA) × B. pumpellianus ssp. dicksonii (AABB) was very complete. The pairing in a 61-cell sample from one hybrid plant was 1.97 IV + 0.51 III + 8.43 II + 1.75 I. Three cells containing a pentavalent, hexavalent or an octavalent were also found. The pairing results show that the A genomes of B. erectus and B. pumpellianus ssp. dicksonii are homologous, and that the A and B genomes are nearly homologous with few gross structural changes. Bromus pumpellianus ssp. dicksonii should be considered a segmental allotetraploid with predominant bivalent pairing.
PROBABLE BASIS OF DIPLOIDIZATION OF BRASSICA JUNCEA COSS
Authors: Prakash Shyam
Published: November 2014

The natural amphidiploid, Brassica juncea, has diploid-like meiotic behaviour. In three duplication-deficiency plants recovered from an interchange heterozygote stock, a large number of chromosomes were involved in multiple associations. It is suggested that this high level of pairing was due to the conjugation of homoeologous chromosomes and that the deficient segment carries a gene (genes) for suppressing such pairing and for maintaining balanced diploid-like behaviour.
A SEX CHROMATIN AND Y BODY SURVEY OF TORONTO NEWBORNS
Authors: Bell A. G. , Corey P. N.
Published: November 2014

Sex chromatin determinations were performed on the amniotic membranes of 72,739 newborns in 11 Toronto hospitals. These analyses, carried out between I October 1967 to 31 May 1971, identified 40 XXY subjects, 16 XXX, 1 XO, 1 XXYY as well as 9 mosaics of various constitutions. A further five subjects with normal karyotypes but discrepant phenotypic sexes were found in this population. 1735 of the males (of the above) were also examined for fluorescent Y bodies. An additional 3660 males, born between 1 June 1971 and 30 September 1971, were examined for Y bodies only. Five XYY newborns were identified by the Y body screening as well as one XY/XXY and three more XXY subjects. Incidence figures for the various sex chromosome aberrations were not significantly different from similar figures derived from other studies. A not unexpected maternal age effect on the incidence of X chromosome abnormalities was demonstrated, older mothers having a higher risk. A pronounced parity effect was noted, first born offspring having a greater risk. A seasonal variation in the incidence of XXY births was found; a peak in the incidence during the spring months, followed by a minor second peak in the autumn.
INHERITED VARIANTS OF α1-ANTITRYPSIN: A NEW ALLELE PiN
Authors: Cox Diane Wilson , Celhoffer Lynne
Published: November 2014

A new inherited variant of α1-antitrypsin (protease inhibitor or Pi) has been found in five individuals of a family of Welsh origin. The new allele is called PiN, as the α1AT product migrates in acid starch gel between the products of the PiM and PiP alleles. The individuals carrying the PiN allele are all of Pi type MN. The new variant has been compared in several electrophoretic systems with other variants migrating in a similar region by acid starch gel electrophoresis (M, P, S, V, W and X). Acid starch gel and crossed antigen-antibody electrophoresis are most suitable for distinguishing the PiN product. By immunofixation electrophoresis, N has a mobility only slightly different from that of M, however the value of this method can be seen for distinguishing other slow variants which cannot be clearly distinguished on acid starch gels. Twenty-three variants of α1AT are now known. Twenty-two of these are electrophoretic variants and one, the null allele (Pi−), produces no α1AT.
THE ORIGIN OF TRIPLOIDY IN CHICK (GALLUS DOMESTICUS) EMBRYOS
Authors: Mong S. J. , Snyder M. D. , Fechheimer N. S. , Jaap R. G.
Published: November 2014

Cytogenetic analysis was made of 1466 chick embryos at one day of incubation. The embryos were from reciprocal crosses of two genetically diverse stocks (G1) and from matings among resulting crossbreds (G2). The overall frequency of heteroploidy was 4.6% in G1 and 5.8% in G2. The difference was not significant but the difference in frequency of triploid embryos (0.5% and 3.1%) was significant. This difference was attributed to the younger age of dams of the group with high frequency of triploidy. Furthermore, the same group of dams produced more triploid embryos when commencing their laying cycle at 19-22 weeks of age than at subsequent ages, 23-27 weeks of age, when their laying cycle had stabilized. The gonosomic complement of 54 triploid embryos was 25 ZZZ: 22 ZWW: 7 ZZW, indicating that about 80% result from failure of meiosis II of oogenesis.
INHERITANCE OF VIRULENCE IN PUCCINIA RECONDITA ON ALLELES AT THE Lr2 LOCUS FOR RESISTANCE IN WHEAT
Authors: Dyck P. L. , Samborski D. J.
Published: November 2014

The inheritance of virulence on the Lr2 alleles for resistance to the leaf rust fungus (P. recondita Rob. ex. Desm.) was investigated using selfed and "backcross" selfed cultures of race 11, F1 cultures of race 9 × race 11, race 11 × race 161 and F1 and F2 cultures of race 9 × race 161. The three host alleles Lr2a, Lr2b and Lr2c were transferred into the wheat varieties Thatcher, Red Bobs and Prelude by a series of backcrosses. Race 11, and probably race 161, have a single recessive gene, p2, for virulence on the three Lr2 alleles and an additional gene(s) that modifies or inhibits the action of the p2 gene on the three host alleles. Lines with the Lr2a gene from Webster were most resistant to the greatest number of cultures, those with Lr2b from Carina were intermediate while those with Lr2c from Brevit and Loros were least resistant. The Lr2 alleles were most effective in the Thatcher background, intermediate in Prelude and least effective in Red Bobs.
A TRANSMISSION ELECTRON MICROSCOPE EXAMINATION OF HEMIPTERAN AND LEPIDOPTERAN GONIAL CENTROMERES
Authors: Gassner George , Klemetson Donna J.
Published: November 2014

A transmission electron micrograph study indicates that the material identified as the centromere in gonial mitotic cells is more localized in the lepidopterans, Ephestia kuehniella (Zeller) and Trichoplusia ni (Hübner), than in the hemipteran, Oncopeutus fasciatus (Dallas). The lepidopteran centromeres are similar in size to the centromeres found in several monokinetic species. In O. fasciatus the mitotic nuclear envelope disappears while the E. kuehniella and T. ni nuclear envelopes persist during division. Factors other than the extent of the centromere material may be involved in making the Lepidoptera more resistant to radiation sterilization than the Hemiptera.
NONPERMISSIVENESS OF STRAIN B FORESCHERICHIA COLITO P1kc; THE ISOLATION OF P1bc
Authors: Chung Young S. , Greenberg Joseph , Donch John
Published: November 2014

P1kc grown on strain K12 of Escherichia coli adsorbs to, kills, lysogenizes and transduces strain B, but its efficiency of plating (e.o.p.) in strain B is 10−6. From the few plaques which form a mutant, P1bc, was derived which grows normally on strain B and has an e.o.p. of 5 × 10−3on K12. P1bc grown on K12 has an e.o.p. of 5 × 10−3on B. This reciprocal restriction is probably attributable to restriction and modification (r and m). P1kc has an e.o.p. of 5 × 10−3on strain B/r. Phage harvested from this infection have an e.o.p of 10−5on strain B and 5 × 10−3on K12. P1kc is restricted on strain B/r only to the extent determined by r and m, and P1bc is not selected under these conditions.
MORPHOMETRIC ANALYSIS OF YEAST CELLS: III. SIZE DISTRIBUTION OF 2-DEOXYGLUCOSE-INDUCED LYSING SCHIZOSACCAROMYCES POMBE CELLS AND THEIR SITES OF LYSIS
Authors: Johnson Byron F. , Lu Calvin , Brandwein Sidney
Published: November 2014

To cultures of Schizosaccharomyces pombe, 2-deoxyglucose (2DG) was added, either as 7 μg/ml during inoculation of the cultures (low dosage), or as 250 μg/ml during the log phase (high dosage). Samples were removed from the cultures, and lysing and non-lysing cells were measured and tabulated. Addition of the high dosage was followed immediately by lysis, with over 85% of the lysing cells found in cytolysis at their primary growing ends Lysis ensued only at the beginning of the stationary phase in the low dosage experiments; 64% of the affected cells lysed at their cell plates. Cells lysing at their primary ends (high dose experiments) were shorter than the controls; cells lysing at their cell plates (low dose experiments) were longer than the controls. The cell division process of the last cell cycle completed in the culture is unusual in its susceptibility to the low initial dose of 2DG, suggesting that cell division metabolism is fundamentally different from wall extension metabolism in the fission yeast.
EFFECT OF SELECTION ON HERITABILITY AND GENETIC CORRELATION OF TWO QUANTITATIVE TRAITS IN MICE
Authors: Cheung T. K. , Parker R. J.
Published: November 2014

The effects of different intensities of single trait directional selection on the heritability and genetic correlation of two quantitative traits in random mating populations of mice were observed during 14 generations. The initial population was divided at random into five groups (A, B, C, D and E). Group A and Group B were under 30% and 60% mass selection for large 6-week body weight, respectively. Group C and Group D were under 30% and 60% mass selection for long 6-week tail length, respectively. Group E acted as control group with no selection applied. In all groups, the parent population consisted of 15 males and 30 females each generation, mated at random.Direct selection had no apparent effect on the heritability of either the trait under selection or the correlated trait over the 14 generations. Heritability of 6-wk tail length was higher than the heritability of 6-wk body weight. Estimates of heritability of 6-wk tail length ranged from 0.15 ± 0.22 to 0.68 ± 0.24, while estimates of heritability of 6-wk body weight ranged from 0.05 ± 0.17 to 0.33 ± 0.09. There was no significant difference among the estimates of genetic correlation between the two traits in the five selection groups. Estimates of realized genetic correlation between 6-wk body weight and 6-wk tail length seemed to indicate that more intense selection led to some decrease in genetic correlation between the two traits.
THE GENETICS OF STRIPE, A NEW MORPHOLOGICAL MUTANT IN THE MALARIA MOSQUITO, ANOPHELES STEPHENSI
Authors: Sakai R. K. , Iqbal M. P. , Baker R. H.
Published: November 2014

Genetic studies of a new morphological mutant, Stripe (Stp), in the malaria vector mosquito, Anopheles stephensi, suggest that the mutant phenotype is determined by a single major allele which is codominant to the wild-type allele. Stripe is linked to the linkage group II markers, alcohol dehydrogenase (Adh) and acid phosphatase (Acph). The recombination values are Stp - Adh = 33.33% ± 1.53, Adh - Acph = 11.75% ± 1.05, and Stp - Acph = 42.93% ± 1.61. The gene sequence is Stp - Adh - Acph.