bluuebunny/crossref_metadata_2025 huggingface dataset:
DEVELOPMENT AND CHARACTERISTICS OF A DISOMIC-1D ADDITION LINE OF DURUM WHEAT
Authors: Joppa L. R. , Bietz J. A. , McDonald C.
Published: November 2014

A pair of chromosomes from Chinese Spring hexaploid wheat (Triticum aestivum L.) was added to the tetraploid durum wheat (Triticum turgidum L.) cultivar Langdon. Crosses between this disomic-addition line and Chinese Spring ditelosomic 1DL produced progeny with 14 pairs + 1 heteromorphic bivalent + 6 univalents (14″ + t1″ + 6′). Therefore, this durum line with 15 pairs of chromosomes is a 1D-disomic addition line to Langdon durum wheat. Seed from the 1D-disomic addition line produced two high-molecular-weight glutenin polypeptide subunits not present in durum wheats, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. These polypeptides were similar to those present in Chinese Spring. Semolina milled from seed of the 1D-disomic addition line had very strong mixing properties, as determined by the micro-mixograph, and 2% higher protein than the recurrent parent Langdon or other durum varieties. The amino acid content of the line was similar to that of the other durums.
ESCAPE FROM MATING-TYPE INCOMPATIBILITY IN BISEXUAL (A+a)NEUROSPORAHETEROKARYONS
Authors: DeLange A. M. , Griffiths A. J. F.
Published: November 2014

In Neurospora crassa, strains of opposite mating type generally do not form stable heterokaryons because the mating type locus acts as a heterokaryon incompatibility locus. However, when one A and one a strain, having complementing auxotrophic mutants, are placed together on minimal medium, growth may occur, although the growth is generally slow. In this study, escape from such slow growth to that at a wild type or near-wild type rate was observed. The escaped cultures are stable heterokaryons, mostly having lost the mating type allele function from one component nucleus, so that the nuclear types are heterokaryon compatible. Either A or a mating type can be lost. This loss of function has been attributed to deletion since only one nuclear type could be recovered in all heterokaryons except one, but deletion spanning adjacent loci has been directly demonstrated in a minority of cases. Alternatively when one component strain is tol and the other tol+(tol being a recessive mutant suppressing the heterokaryon incompatibility associated with mating type), escape may occur by the deletion or mutation of tol+, also resulting in heterokaryon compatibility. An induction mechanism for escape is speculated upon.
MAMMARY TUMOR VIRUS AND HOST GENOME IN THE TRANSMISSION AND CAUSATION OF MAMMARY TUMORS IN MICE
Authors: Heston W. E. , Parks Wade P.
Published: November 2014

A review of the genetics of mammary tumor virus is presented in which the discoveries and hypotheses are given as they have historically developed.
INHERITANCE OF PERICARP THICKNESS IN SHORT SEASON MAIZE INBREDS
Authors: Ho L. C. , Kannenberg L. W. , Hunter R. B.
Published: November 2014

Pericarp thickness of 16 short-season inbred lines of corn (Zea mays L.) ranged from 35 to 126 μm with an overall mean of 82 ± 5 μm. The mode of inheritance of this trait was studied in two experiments. Two inbreds representing the extremes of pericarp thickness, their F1and F2generations, and both first generation backcrosses were included in Experiment 1. The inheritance of pericarp thickness proved to be quantitative in nature. All gene effects were significant, but epistatic effects, particularly dominance × dominance, were the largest in this particular cross. This could have resulted from bias due to linkage disequilibrium. Experiment 2 was a diallel set of 5 inbreds to include the parents and all possible single crosses, but not reciprocals. Diallel graphic analysis of these data indicated partial dominance for thin pericarp with minimal epistasis. Analysis II of Gardner and Eberhart showed that the mean square for line effects was several times larger than the heterosis estimates, indicating a high level of additive gene effects. The narrow sense heritability estimate was 72%. Thus selection for specific pericarp thickness should be effective and relatively rapid.
CHIASMA FREQUENCIES IN PRIMARY TRISOMICS OF PEARL MILLET
Authors: Manga V.
Published: November 2014

Seven primary trisomics were obtained in the progeny of an autotriploid Pennisetum typhoides (Burm.) S. &H. The trisomics could be distinguished from the diploids and from one another morphologically and were designated Dwarf, Bush, Slender, Semidwarf, Purple, Robust and Pseudonormal. In Purple and Pseudonormal the mean chiasma frequencies were significantly higher than in the diploid sibs but in Dwarf the mean chiasma frequency was significantly lower. In the other trisomics the chiasma frequencies did not differ from the diploid sibs. The trivalent frequencies and configurations varied in the different trisomics and no correlation was noticed between the length of the chromosome and trivalent frequency but one was observed between trivalent frequency and chiasma frequency.
AMYLASE ISOZYMES IN THE MOSQUITO, CULEX TRITAENIORHYNCHUS
Authors: Sakai Richard K. , Lateef Shahida , Iqbal M. Perwaiz , Tahir Muhammad K. , Baker Richard H.
Published: November 2014

A survey of laboratory stocks of Culex tritaeniorhynchus Giles has uncovered the presence of four electrophoretic variants and one apparent null allele of amylase. Linkage experiments with heterozygous males indicate that amylase is sex-linked. The gene sequence is w (white eye) — Amy (amylase) – M (sex), and the recombination frequencies are: w – Amy = 6.02%, Amy – M = 1.35% and w – M = 7.37%.
GENETIC EFFECTS AND GENETIC EFFECT × YEAR INTERACTIONS AT THREE GENE LOCI IN SUBLINES OF A MAIZE INBRED LINE
Authors: Russell W. A.
Published: November 2014

"Isogenic" lines of maize (Zea mays L.) inbred B14, differing by single marker genes and chromosome segments linked to these genes, were used to study gene action in the inheritance of 10 plant, ear, and grain characters. The 27 genotypes representing all combinations of the homozygous and heterozygous genotypes at three loci, rp, wx, and ws, were evaluated for three years. Highly significant differences among genotypes were observed for eight characters; genotype × year interactions were highly significant for seven characters, which included the two characters that were not different for genotypes. Additive effects were most important, followed by additive × additive epistasis, and dominance was relatively unimportant. Also, additive effects × years were generally the most important of the interactions, but except for the two characters that did not have significant differences among genotypes, the genotypic effect × year interactions were of considerably lesser importance than the genotypic effects.
THE KARYOTYPE OF THE AUSTRALIAN SWAMP BUFFALO (BUBALUS BUBALIS)
Authors: Toll G. L. , Halnan C. R. E.
Published: November 2014

The karyotype of the Asian Swamp buffalo has previously been reported for beasts of Thailand and Malaysia. A diploid number of 48 was observed which was different to that found for the River buffalo (2n = 50). This report describes the karyotype of Australian Swamp buffalo, which has proved in agreement with that of the Asian Swamp buffalo. An hypothesis is advanced to account for movement of buffalo down the island chain from Malaya to Australia.
GEOGRAPHIC VARIATION OF THE CHROMOSOMAL POLYMORPHISM INDROSOPHILA FLAVOPILOSA
Authors: Brncic Danko
Published: November 2014

Natural populations of the Chilean species Drosophila flavopilosa Frey are polymorphic for the banding sequences in the fifth chromosome due to the existence of four paracentric inversions. Qualitative analysis of the polymorphism demonstrated that there are seasonal fluctuations and geographic variations of two kinds: altitudinal gradients and a north-south gradient. In addition, the northernmost and southernmost samples examined are polymorphic only for one inversion (inversion "B"). In the light of previous experimental evidence, it was concluded that the seasonal fluctuations and elevational differences are probably controlled by weather conditions, especially temperature. However, the observed differences between the central and marginal populations require another type of interpretation, similar to that postulated for other species that exhibit the same pattern of chromosomal variation. A photomicrographic map of the Standard banding pattern of the salivary gland polytene chromosomes of D. flavopilosa is presented.
CONTRIBUTION A L'ETUDE CYTOTAXONOMIQUE D'ESPECES MEDITERRANEENNES D'ANEMONE ET DE LEURS HYBRIDES
Authors: Maïa Nicole , Venard P.
Published: November 2014

Statistical comparison of the caryotypes of the four Mediterranean Anemone species: A. palmata L., A. coronaria L., A. pavonina Lamk. and A. hortensis L., is based on the dispersion areas of the T/Θ and L/C parameters estimated for each chromosomal pair. Chromosome alteration has been observed in both interspecific hybrids obtained. These alterations are more marked when the genome is transferred into an alien cytoplasm. The F1 hybrid A. pavonina × A. hortensis is fertile with some meiotic abnormalities. Sterility of the A. pavonina × A. coronaria F1 hybrid is caused by the failure of pairing. Chromosomal doubling by colchicine restored fertility. Phylogenic relations as established by morphological, biochemical and caryotypic characters, as well as by meiotic behavior of interspecific hybrids, are in good agreement. The lack of introgression of new characters into the cultivated species A. coronaria is due to interspecific sterility barriers. Nevertheless, the introduction of the coronaria genome into the cytoplasm of pavonina would be a source of male-sterility at the tetraploid level.
DIFFERENTIAL EGG CANNIBALISM AMONG LARVAE OF TRIBOLIUM CASTANEUM AS INFLUENCED BY THE ANTENNAPEDIA MUTATION
Authors: Fogle Thomas A. , Englert Du Wayne C.
Published: November 2014

Egg cannibalism by antennapedia and wild-type larvae of Tribolium castaneum was analyzed for two age groups (14 and 15 days old) with egg densities of 100 and 400. The effects of larval density and egg genotype (+ or ap) were also analyzed. The + larvae consumed more eggs than ap larvae at both ages for the egg densities tested. Both strains were more cannibalistic at 14 days, consumed a higher percentage of eggs when egg density was increased among 14-day larvae, and tended to consume slightly more eggs of the opposite genotype when they were provided independently. However, neither strain discriminated between eggs of differing genotype when both were provided simultaneously. Egg cannibalism of the + strain increased when both genotypes of eggs were available. Reciprocal F1 hybrid larvae were similar in cannibalistic ability to the strain which served as the male parent. Larvae from "F2 recovered" ap beetles cannibalized fewer eggs than either original strain or the heterozygotes, further implicating the possible pleiotropic effect of the ap mutation on egg cannibalism.
THE CYTOGENETIC STRUCTURE OF A 56-CHROMOSOME DERIVATIVE FROM A CROSS BETWEENTRITICUM AESTIVUMANDAGROPYRON ELONGATUM(2n = 70)
Authors: Dvořák Jan
Published: November 2014

Chromosome pairing was studied in a number of hybrids involving a 56-chromosome wheat-Agropyron derivative, PW 327. PW 327 originated from the cross, Triticum aestivum cv. Chinese Spring (Chinese Spring × A. elongatum, 2n = 70). In hybrids between PW 327 and T. aestivum a number of multivalent chromosome associations were formed at metaphase I. These multivalents result from interchanges which occurred among wheat chromosomes 1A, 1D, 2A, 2D, 4D and 6D of PW 327. One chromosome of the Agropyron chromosome set of PW 327 occasionally pairs with wheat chromosome 3B. The rest of the Agropyron chromosomes present in PW 327 do not pair with the chromosomes of T. aestivum. It is proposed that the set of Agropyron chromosomes present in PW 327 is not an intact genome of decaploid A. elongatum but rather a modified synthetic genome combining chromosomes and/or chromosome segments from different genomes of the Agropyron parent. The incorporation of duplication-deletions into synthetic genomes of natural polyploids is discussed and it is shown that the set of Agropyron chromosomes which is present in PW 327 carries at least one such duplication-deletion. Pairing between chromosomes of diploid and decaploid A. elongatum was studied in a 56-chromosome hybrid from a cross between an amphiploid, T. aestivum × A. elongatum (2n = 14), and PW 327. It appeared that at least four chromosomes of these two Agropyrons occasionally paired with each other in this hybrid in which the diploidizing system of wheat was active. The relationship between chromosomes of diploid and decaploid A. elongatum is discussed.
MEIOTIC BEHAVIOR OF EXTRA HETEROCHROMATIN IN THE TOMATO: EFFECTS ON SEVERAL VITAL PROCESSES
Authors: Quirós Carlos F.
Published: November 2014

The cytological behavior during meiosis of extra constitutive heterochromatin and the effects of such additions to the tomato genome were investigated. The main source of extra heterochromatin was 2S∙2S, a completely heterochromatic isochromosome carrying a nucleolar organizer in each of its arms. Meiotic behavior of a half-heterochromatic, tertiary chromosome 5L∙2S in the presence of 2S∙2S was studied. Wehn 2S∙2S chromosomes were present in more than two doses, achiasmatic simultaneous pairing of three, four and five arms of these chromosomes was observed. "Ectopic" pairing of 2S∙2S with heterochromatin of nonhomologous chromosomes was also observed. It is postulated that "ectopic" pairing neutralized in part the high percentage of anaphase I equational division of the 2S∙2S chromosomes. In some individuals the 2S∙2S chromosome was found organizing an extra, smaller-than-normal nucleolus during meiotic prophase. Conspicuous nucleolar vacuoles were also observed in the progenies of plants carrying 2S∙2S extra chromosomes. It was found that the 2S∙2S chromosome alters diakinesis association and segregation of the 5L∙7S chromosome when both are in the same cell. 2S∙2S chromosomes reduced chiasma frequency, which was also accompanied by reduction of crossing-over for some of the tested gene intervals when 2S∙2S was present in one dose. No effects of 2S∙2S on chromosome pairing of interspecific hybrids were detected. Another effect produced by the addition of 2S∙2S chromosomes was expressed as leaf necrosis in some individuals.
RELATIONSHIP OF TAXA IN GENUS MEDICAGO AS REVEALED BY HYBRIDIZATION. VIII. SECTION ROTATAE
Authors: Lesins K. , Sadasivaiah R. S. , Singh S. M.
Published: November 2014

Members of Medicago section Rotatae Boiss., M. bonarotiana Arc. could be intercrossed readily and their F1's had normal pollen fertility. Difficulties with long period of seed after-ripening were overcome by treating seeds at 55° or 64 °C for 14 or 10 days, respectively. Anthocyanin leaf pigmentation was inherited in a monogenic mode, pigmentation being dominant. In the inheritance of leaf notchedness, pod shape and pod spininess, at least two genes (three alleles in pod spininess) were involved. Characters: notched leaves, biconvex pod shape, and spininess of pods were found to be dominant. Variability in the expression of these characters and the rate of different mortality at seed germination often made classification difficult. Linkage of genes determining characters was analysed in one case and it was found that the determining genes segregated independently. Pod characteristics studied in F2's indicated that M. blancheana Boiss., M. rotata var. rotata Heyn, M. rotata var. eliezeri Heyn, M. blancheana var. blancheana Heyn, also M. rotata ssp. blancheana Ponert and M. rotata ssp. eliezeri Ponert were very probably of hybrid origin. At species rank, in sect. Rotatae, we consider M. rotata Boiss. and M. bonarotiana Arc. as after their intercrossing segregates in F2 matched with descriptions and figures of plants named by different authors as separate taxanomic entities.
GENETIC VARIATION AND THE ECOLOGICAL PARAMETER "FOOD MEDIUM" IN CAGE POPULATIONS OFDROSOPHILA MELANOGASTER
Authors: Alahiotis S.
Published: November 2014

Impressive effects of the ecological factor "food medium" upon the frequencies of the lethal-bearing second chromosomes in Drosophila melanogaster were found in cage populations originated from a common gene pool. Allozyme frequencies for two second enzyme loci were also determined. The lethal frequencies found were higher when the environment was restrictive than when it was favorable. Moreover, the lethal frequencies were higher in populations of smaller size than in those of greater. The role of the lethal genetic variants in the structure of populations is discussed.
EXPECTED GENETIC GAINS WHEN MALE AND FEMALE PARENTS ARE SELECTED FOR THE SAME OR DIFFERENT QUANTITATIVE TRAITS
Authors: Yamada Yukio , Scheinberg Eliyahu
Published: November 2014

In some breeding programs selection criteria in males and females are not the same. For example, growth traits and semen quality are important in males while reproductive traits and support of the young are more important in females. In this case, the prediction of genetic gains in a trait in males and a different trait in females cannot be made since the appropriate formulae are not available at present. By partitioning the effect of selection in the male and female parents into four paths, e.g. sire to son, sire to daughter, dam to son and dam to daughter and by introducing the appropriate genetic correlation coefficient between males and females, the formulae for the expected genetic gains in either sex are derived. This is followed by further considerations of sex dimorphism and selection under various specified conditions.
GENETIC STUDIES ON ALIEN CHROMOSOME ADDITION TO A DURUM WHEAT. I. SOME CHARACTERISTICS OF SEVEN MONOSOMIC ADDITION LINES OFAEGILOPS UMBELLULATACHROMOSOMES
Authors: Makino Tokuhiko
Published: November 2014

Seven different monosomic addition lines of Triticum durum var. melanopus strain India for Aegilops umbellulata chromosomes were developed and identified by comparison of morphological and cytological characteristics of 29-chromosome plants. On the basis of cytological data obtained, probable causes of differential transmission rates of the univalent chromosomes are discussed.
THE EFFECT OF ACCESSORY CHROMATIN ON CHIASMA DISTRIBUTION IN MAIZE
Authors: Ward Edward J.
Published: November 2014

From an analysis of metaphase I bivalent configurations in Zea mays L. it was possible to determine the effects of two supernumerary elements on chiasma formation. Both the B chromosome and abnormal chromosome 10 increased chiasma frequency. In addition to enhancing total exchanges, both elements caused a redistribution of chiasmata from distal to more proximal locations.
THE G AND Q BANDING PATTERN OF ELLOBIUS LUTESCENS. A UNIQUE CASE OF SEX DETERMINATION IN MAMMALS
Authors: de la Maza Luis M. , Sawyer Jeffrey R.
Published: November 2014

The karyotype of the microtine Ellobius lutescens Th., was analyzed using the G and Q banding techniques. One of the chromosomes of the first pair has the same bands in both sexes while the other member of the pair is unique to each sex. We propose that the sex determining mechanism of Ellobius lutescens is located in these chromosomes. The genetic burden imposed on this species due to this constitution is discussed.
THE FUSION OF ERYTHROCYTES BY TREATMENT WITH PROTEOLYTIC ENZYMES AND POLYETHYLENE GLYCOL
Authors: Hartmann James X. , Galla J. D. , Emma D. A. , Kao K. N. , Gamborg O. L.
Published: November 2014

Polyethylene glycol (PEG) has been utilized to induce homokaryocyte formation in avian and mammalian erythrocytes previously treated with proteolytic enzymes. PEG of molecular weight 6,000–7,500 was found superior to 1,500 and 20,000 MW PEG. Cells exposed to protease alone, prior to PEG treatment, fused to a high degree (60–95% multinucleated cells), whereas trypsin or pepsin treatment alone allowed very little fusion (2.5%). Trypsin lowered the effectiveness of protease when used in combination. Cells which were not treated with proteolytic enzymes agglutinated in the presence of PEG but did not fuse to a significant extent (0.01%). Fusion was also markedly dependent upon the rate at which PEG was eluted during the fusion process. Electron microscopy indicated that fusion began during the elution of PEG from the agglutinated cells.
CYTOLOGICAL EFFECTS OF AN ORGANIC PHOSPHATE PESTICIDE ON HUMAN CELLS IN VITRO
Authors: Alam M. T. , Kasatiya S. S.
Published: November 2014

This investigation was undertaken to determine the radiomimetic effects in vitro of the insecticide guthion [azinophos-methyl; O,O-dimethyl S-(4-oxobenzotriazino-3-methyl) phosphorodithioate] on two human cell lines, diploid (WI-38) and heteroploid (HEp-2). In WI-38 cells, dosages of 120, 140 and 160 μg/ml of guthion were effective in inducing an average chromosome breakage of 0.042, 0.058 and 0.165 respectively per cell. In control cells, the mean number of breaks per cell was 0.011. Chromosome breakages were significantly higher in treated cells. Since guthion prevents cells from entering into mitosis during treatment, the number of mitotic cells decreases rapidly following treatment with higher concentrations. Similar dosages in treated HEp-2 cells also induced a high incidence of chromosome aberrations, the most common being chromatid breaks and exchanges. Infrequently noted were mild failure of condensation, despiralization, secondary constrictions, gaps, dicentric chromosomes and pulverization. To date, this study reaffirms previous findings of the potentially hazardous, mutagenic effects of guthion.
DIMORPHIC NUCLEOLAR ORGANIZER REGIONS IN THE FROG RANA BLAIRI
Authors: Ward Oscar G.
Published: November 2014

The nucleolar organizer-specific staining procedure, ammoniacal silver (Ag-AS), has been used to study the distribution and size of the nucleolar organizer regions (NORs) in chromosomes of the frog Rana blairi (Mecham, Littlejohn, Oldham, Brown and Brown). The somatic metaphase karyotype of this frog is similar to that of other frogs of the Rana pipiens species complex, numerically (2n = 26) and morphologically. Secondary constrictions are detectable in untreated Giemsa-stained metaphase preparations as achromatic gaps in the long arms of a pair of submetacentric chromosomes (no. 10). These constrictions are the only regions which are deeply stained with the Ag-AS method and are thus identified as the nucleolar organizer regions (Ag-NORs). In each of the three individuals, the Ag-NORs as visualized on the homologues are of unequal length.
X-RAY INDUCED PERICENTRIC INVERSIONS IN ANOPHELES ALBIMANUS
Authors: Rabbani M. G. , Seawright J. A. , Kitzmiller J. B.
Published: November 2014

Sixteen different pericentric inversions, ten on chromosome 2 and six on chromosome 3, have been isolated and characterized. The partial sterility in the inversion heterozygotes ranged from about 28 to 50%. Contrary to theoretical considerations, a curvilinear relationship exists between inversion length and partial sterility, whereby a reduction in sterility was noted for progressively longer inversions. The break-points are distributed randomly over the autosomes, but are observed more frequently in the areas of the salivary gland chromosomes where diffuse and broken bands of variable stainability are located.
HOMOEOLOGOUS CHROMATIN EXCHANGE IN A RADIATION-INDUCED GENE TRANSFER
Authors: Dvořák J. , Knott D. R.
Published: November 2014

Some of the ionizing-radiation-induced translocations between alien and wheat chromosomes show no deleterious effects and are transmitted normally through the pollen. Translocations of this type will be called "compensating". In one such compensating translocation, designated T4, a segment of Agropyron elongatum (Host.) P.B. chromosome 7el1with gene Lr19 controlling resistance to leaf rust was transferred into wheat chromosome 7D. The T4 translocation was found to have involved chromosome arms 7el1α and 7DL. The pairing relationships of Agropyron telosome 7Eα with telosomes 7AL, 7BL, 7DS and 7el1α was studied in wheat-Aegilops speltoides Tausch. hybrids. The 7Eα telosome paired with 7DS and, therefore, is homoeologous with it. It did not pair with 7AL, 7BL, and 7el1α. Hence 7AL, 7BL, 7DL, 7el1α must be homoeologous. Consequently, chromatin in the long arm of chromosome 7D was replaced with homoeologous chromatin of the Agropyron chromosome in the T4 translocation.
INVITATION PAPER ANIMAL BREEDING TODAY — ITS DIMENSIONS AND ACCOMPLISHMENTS
Authors: Fredeen H. T.
Published: November 2014

Since its inception early in the present century, the science of animal breeding has been directed toward the effective application of quantitative genetic theory for improvement of animal populations. This has involved developing and refining biomedical techniques for estimating genetic parameters, designing mating systems for efficient utilization of additive and nonadditive genetic variance, developing criteria of net merit that have both genetic and economic relevance, and designing practical testing procedures for evaluating genetic differences in productive merit. While the main*** emphasis has been on quantitative inheritance, attention has also been given to qualitative genetics, specifically in respect of defective conditions and disease resistance, and to the implications of chromosomal aberrations. Controlled laboratory studies, designed to test genetic theory, have demonstrated the considerable potential that exists for improving animal productivity through manipulation of the genetic variability in animal populations. To date, relatively little of this potential has been utilized in commercial livestock populations and, while substantial genetic improvement has been achieved by the process of breed substitution, it is clear that the science of animal breeding has progressed far beyond its practical application. For this reason, the emphasis in the science has gradually shifted from refinement of theory to the more practical issues involved in effective application at the industry level.
THE EFFECT OF COLCHICINE ON CHROMOSOME PAIRING
Authors: Thomas J. B. , Kaltsikes P. J.
Published: November 2014

Beginning at 120 hours prior to first metaphase of meiosis (MI) a 0.03% aqueous solution of colchicine was injected into the boot of pentaploid (hexaploid triticale × tetraploid wheat) hybrids developing at 20 °C ± 1° under continuous illumination. Colchicine applied 40 h or less prior to MI had no effect on chromosome pairing, while its application 40 h or more prior to MI induced a steady decline, culminating in a 40% reduction in chromosome pairing at about 80 h from MI. Between 48 and 35 h before MI (late premeiotic interphase to early zygotene) meiocytes underwent a period of active nucleolar fusion. The time, therefore, at which the colchicine sensitive aspects of chromosome pairing were completed coincided with the completion of nucleolar fusion. From comparison with other findings it was concluded that there is a colchicine sensitive bouquet stage which appears in leptotene and early zygotene; this bouquet is responsible for active nucleolar fusion and final close association between homologous chromosomes.
DIALLEL ANALYSIS OF LEAF NUMBER AND DURATION TO MID-SILK IN MAIZE
Authors: Bonaparte E. E. N. A.
Published: November 2014

The diallel cross technique was used to study the mode of inheritance of leaf number and duration to mid-silk in six inbred lines of maize (Zea mays L.). Leaf number showed partial dominance, and the additive gene effects accounted for a high proportion of the total variation. The narrow and broad heritabilities were both high. Leaf number was controlled by at least one effective factor. Both additive and dominance components were responsible for the expression of duration to mid-silk. The narrow and broad heritabilities were both high. Duration to mid-silk was controlled by at least four effective factors.
IDENTIFICATION AND NOMENCLATURE FOR G-BANDED BOVINE CHROMOSOMES
Authors: Lin C. C. , Newton D. R. , Church R. B.
Published: November 2014

A reliable trypsin-Giemsa banding technique for producing clearly differentiated G-bands on bovine chromosomes was introduced. Unequivocal identification of individual bovine chromosome pairs is now possible. A system similar to the standardization of human chromosomes was proposed for the nomenclature of the G-bands. This scheme of nomenclature will facilitate the identification and recording of chromosome aberrations in this species.
INDUCTION OF MUTATIONS BY CHEMICALS AND GAMMA RAYS IN MUTANTS OF YEAST REFRACTORY TO UV-MUTAGENESIS
Authors: Nasim A. , Hannan M. A.
Published: November 2014

Radiation-sensitive mutants of Schizosaccharomyces pombe, known to be refractory to UV-mutagenesis, were tested for mutability caused by treatments with chemicals and gamma rays. One such mutant (rad3) was studied over a wide range of UV doses to compare the kinetics of its mutational response to that of the wild type. All such comparisons were carried out using a forward mutation system. Data show that, unlike UV, the chemical mutagens as well as gamma rays produced mutations (although at reduced frequency), in the strains of S. pombe tested, indicating the existence of an additional mechanism(s) for chemical and gamma ray induced mutations. These observations are discussed as these relate to the pathways for repair of mutational damage in yeast.
INDEPENDENCE OF DURATION OF MEIOSIS AND CHROMOSOME PAIRING IN HEXAPLOID TRITICALE
Authors: Roupakias D. G. , Kaltsikes P. J.
Published: November 2014

The duration of meiosis, its stages, and pollen maturation at 20 °C were determined in six hexaploid triticales (× Triticosecale Wittmack) which differed in the number of univalents per pollen mother cell at metaphase I (0.67 to 2.43). Meiosis lasted from 46.5 to 53.3 h; these estimates are longer than others previously reported for hexaploid triticale (34–37 h) grown under the same conditions. The quartet stage lasted from 7.1 to 8.0 h while pollen maturation took from 9.5 to 11.2 days. Apart from possible genotypic differences, and subjective judgements as to the beginning of meiosis, the present estimates include the stage of nucleolar fusion (average duration 6.0 h) as part of meiotic prophase. A strong positive correlation (r = 0.99) was found between total duration of meiosis and that of zygotene plus pachytene, the stages during which chromosome pairing is thought to occur. These two stages combined accounted for approximately 46% of the total duration of meiosis; even in the triticale with the shortest meiotic duration these two stages lasted longer than in rye (Secale cereale L.). As no relationship could be demonstrated between the total duration of meiosis, or of zygotene plus pachytene, and the number of univalents per PMC, it is concluded that time is not a limiting factor for chromosome pairing in triticale.
CONTROL OF RIBOSOMAL RNA GENE MULTIPLICITY IN WHEAT
Authors: Liang G. H. , Wang A. S. , Phillips R. L.
Published: November 2014

Ribosomal RNA gene multiplicities are reported for various monosomic, tetrasomic, and nullisomic-tetrasomic compensating types of wheat in the Chinese Spring background. Several diploid and tetraploid species as well as three varieties of hexaploid Triticum aestivum also were studied for the level of DNA/rRNA hybridization at the three ploidy levels. The results confirm that all four nucleolus organizer chromosomes 1 A, 1B, 6B, and 5D of wheat contain rRNA genes and lead one to ask whether 1B may be the only one that behaves in a relatively additive fashion in different aneuploid conditions and whether the remaining five homoeologous chromosomes of homoeologous sets 1, 5, and 6 and perhaps other chromosomes contain factor(s) that control the total number of rRNA genes. The proportion of rDNA in diploid, tetraploid and hexaploid wheats was similar suggesting that the number of rRNA genes may have increased proportionally with ploidy level apparently representing balanced conditions regarding the control of rRNA gene multiplicity. The number of rRNA genes in hexaploid wheat varieties, however, was genotype dependent; Atlas 66 and Chinese Spring wheat varieties possessed more rRNA genes than Era.
CHROMOSOME ABERRATIONS PRODUCED BY 5-BROMODEOXYURIDINE WITH CONCURRENT EXPOSURE TO LONG WAVELENGTH UV IN ZEA MAYS ROOT TIP CELLS
Authors: Verma R. S. , Cummins J. E. , Walden D. B.
Published: November 2014

The influence of bromodeoxyuridine (BrUrdR) on the pattern and level of chromosome damage in Zea mays L. root tip cells is described. In some experiments long wavelength ultraviolet light was employed to convert the bromodeoxyuridine in DNA to its photoproduct. BrUrdR treatment produced a marked decrease in the mitotic index and a high proportion of the mitotic cells bore chromosome damage. Following a BrUrdR treatment of 5 h the proportion of damaged cells increased from 20% to 60% during the 20 h following treatment; then the proportion decreased sharply to less than 20%. Root tips treated as above followed by an exposure to long wavelength ultraviolet radiation (UV) had a proportion of damaged cells (80% at 20 h) only slightly greater than those not exposed to UV up to 20 h after treatment. Unlike the unirradiated BrUrdR substituted root tips, the proportion of damaged cells remained high 25 h after treatment. Furthermore, the spectrum of chromosome aberrations differed between irradiated and unirradiated BrUrdR substituted cells. Root tips exposed to long wavelength UV alone showed some damage that was limited to a stage in the cell cycle of irradiated root tips. Analysis of the BrUrdR treated corn DNA by cesium chloride density centrifugation showed that BrUrdR substitution for thymidine in DNA was extensive. Further experiments demonstrated that a large BrUrdR pool was not carried into the rounds of replication following BrUrdR removal from the medium. Nevertheless a small pool of halogenated pyrimidine was observable after BrUrdR removal from the medium.
DIALLEL AND PATH COEFFICIENT ANALYSIS OF TALL FESCUE (FESTUCA ARUNDINACEA) REGROWTH UNDER CONTROLLED CONDITIONS
Authors: Sleper D. A. , Nelson C. J. , Asay K. H.
Published: November 2014

Relationships among leaf elongation rate, leaf width, leaf area expansion rate, number of tillers/plant, and net CO2 exchange (NCE) with total forage yield/plant of tall fescue, Festuca arundinacea Schreb., were studied in a controlled environmental chamber. Among progeny of a 6 × 6 diallel, number of tillers/plant was correlated highly significantly (1% level) with total forage yield/plant (r = 0.697). Path coefficient analyses showed that both tillers/plant and yield/tiller had large positive direct effects on total yield/plant. Utilizing a diallel analysis it was found that additive genetic effects were most important for all traits except for NCE. Progenies did not differ significantly for NCE. Nonadditive genetic effects, although of less magnitude than additive effects, were also found to be important for number of tillers/plant and yield/tiller. Highest broad sense heritabilities were found for number of tillers/plant, yield/tiller, and yield/plant with values of 69, 66, and 66%, respectively
EVIDENCE FOR A 1R/3R TRANSLOCATION IN THE KHARKOV/DAKOLD WHEAT-RYE ADDITION SET
Authors: Zeller Friedrich J.
Published: November 2014

By crossing Kharkov/Dakold wheat-rye addition line I with several other wheat-rye additions and a 1B/1R substitution and by analyzing the chromosome pairing in the pollen mother cells of the F1 hybrids, it was found that the rye chromosome in the addition line is translocated, being composed of segments of rye chromosomes 1R and 3R, respectively.
LIQUID NITROGEN STORAGE AND HUMAN CHROMOSOME COMPOSITION OF HUMAN-MOUSE HYBRID CELLS
Authors: Rushton Alan R.
Published: November 2014

The human chromosome complement of eight human-mouse hybrid cell strains was studied with fluorescent banding before and after rejuvenation of these cells from liquid nitrogen storage. The karyotype remained essentially stable in several cell strains, while in others both human and mouse chromosomes were lost. A third group demonstrated loss of only human chromosomes. The loss of particular human chromosomes after the rejuvenation process was shown to be statistically significant in four of the eight hybrid cell strains. These preliminary results suggest that karyotypic constancy cannot be assumed in human-mouse hybrid cells subjected to rejuvenation from liquid nitrogen storage.
CYTOLOGICAL EFFECTS OF MICROWAVE RADIATION IN CHINESE HAMSTER CELLS IN VITRO
Authors: Alam M. T. , Barthakur N. , Lambert N. G. , Kasatiya S. S.
Published: November 2014

Cytological effects were investigated in the Chinese hamster cell line (CHO-K1) exposed to microwave radiation of 2450 MHz frequency and incident power of 25 to 200 W for a period of 30 min. Nuclear vacuoles, pycnotic and decondensed chromosomes were observed in cells exposed to 25 W under elevated temperature conditions (uncontrolled temp). In addition a significant increase in chromosomal breakages/cell was observed. Cells exposed to relatively higher power, 75-200 W, under hypothermic conditions (29 °C) revealed no significant increase in either nuclear vacuoles or other chromosomal anomalies over control cells. Radiation-induced temperature elevation appears to be an essential factor in the cytological effects of microwave.
HYPERTHERMIA AND HOST-CELL REACTIVATION OF ADENOVIRUS 12
Authors: Lam P. , Stich H. F.
Published: November 2014

Exposure of cultured human fibroblasts to hyperthermia delayed the host-cell reactivation of UV-irradiated human adenovirus type 12 (AD12). The experimental design consisted of irradiating human AD12 with UV doses ranging from 180 to 1800 ergs/mm2, infecting human cell populations at 37 °C, exposing the infected cells for 7 h to 39.5 °C and 41.8 °C, returning them to 37 °C and estimating the frequency of cells with intranuclear viral inclusion bodies (IB) 41 and 89 h after hyperthermia treatment. Hyperthermia reduced the fractions of fibroblasts with viral IB in the 41 h samples. By 89 h the capacity to form IB in the treated cells was comparable to that in control cells. Hyperthermia of 39.5 and 41.8 °C for 7 h did not affect the replication of nonirradiated AD12. The pattern of host-cell reactivation of AD12 following hyperthermia was compared to that in DNA repair deficient xeroderma pigmentosum cell populations.
NULLISOMIC ANALYSIS OF NUCLEOLAR FORMATION IN ZEA MAYS
Authors: Weber David F.
Published: November 2014

When a monosomic plant of a diploid species undergoes meiosis, two haploid and two nullisomic cells are produced. Zea mays L. microspore quartet cells nullisomic for chromosome number 1, 2, 4, 6, 7, 8, 9, or 10 produced by monosomics were analyzed. Cells nullisomic for chromosome 6, as expected, do not contain a nucleolus because chromosome 6 bears the nucleolar organizing region. Cells nullisomic for chromosome 2 contain nucleoli; therefore, the 5S rRNA template on chromosome 2 is not necessary for nucleolar formation. Cells nullisomic for chromosomes 1, 4, 7, 8, 9, or 10 also contain nucleoli; thus, no factors located on these chromosomes are necessary for nulceolar formation at the quartet stage.
A SECOND GENE FOR HAIRS IN BRASSICA OLERACEA AND ITS TENTATIVE LOCATION IN LINKAGE GROUP 4
Authors: Sampson D. R.
Published: November 2014

A dominant gene, Hr-2, from curly kale was studied in 10 F2 and 8 backcross progenies. Hr-2 acted additively with Hr-1 (hairy leaf margins) of linkage group 4 to produce relatively long hairs on the leaves, petioles and stems, whereas Hr-2 — hr-1 hr-1 plants had minute hairs best seen on the lower midribs. The data indicate linkage with 39.9 ± 0.7% recombination between Hr-1 and Hr-2 but the linkage could be spurious. An alternative hypothesis of incomplete penetrance of Hr-2 in an hr-1 hr-1 background is considered. Hr-2 was unmistakably linked to 1e, leaf excrescence, with 10.4 ± 0.6% recombination. If Hr-2 does in fact belong to linkage group 4, the gene order is pg-2 Hr-1 Hr-2 1e.
THE PROPORTION OF ALL POINT MUTATIONS WHICH ARE UNACCEPTABLE: AN ESTIMATE BASED ON HEMOGLOBIN AMINO ACID AND NUCLEOTIDE SEQUENCES
Authors: Boyer Samuel H. , Scott Alan F. , Kunkel Louis M. , Smith Kirby D.
Published: November 2014

Statistical analysis of the distribution of 156 kinds of human haemoglobin β (Hbβ) chain variants suggests that mutations are essentially random in their location. Thus differential fitness, not differential mutability, is the principal source of nonrandom distribution of interspecies differences in Hbβ amino acid sequence. Similar analyses of both the location and the kind of interspecies differences detected among primates support this viewpoint and lead us to estimate that at least 95% of all amino acid substitutions, i.e., nonsynonymous mutations, in Hbβ are functionally unacceptable in homozygous state. Through the combined use of this estimate and the number of nonsynonymous and synonymous substitutions per nucleotide site inferred from comparisons of entire human and rabbit HbβmRNA nucleotide sequences, we calculate (a) ~70% of synonymous Hbβ mutations are adaptively undesirable and (b) the mutation rate underlying all changes is ≤ 10−8nucleotide substitutions per nucleotide site per year. Apart from such calculations, analyses of nucleotide patterns in HbβmRNA as well as in rat preproinsulin mRNA reinforce the notion that a large portion of synonymous mutations are functionally unacceptable and rendered so by selective constraint, at a pretranslational level, of the abundance of particular nucleotide doublets such as CpG.
CHROMOSOME ANALYSIS OFBIDENS CORONATA(COMPOSITAE)
Authors: Butler Merlin G. , Weedon Ronald R.
Published: November 2014

Analysis of the chromosomes of one of the tickseed sunflowers, Bidens coronata (L.) Britt., has revealed chromosome numbers of n = 12, 2n = 24. Eight chromosome pairs were metacentric or near metacentric types with the range of total lengths of 1.5 μm to 2.3 μm. Three chromosome pairs were submetacentric and one chromosome pair was subtelocentric. Two pairs were SAT-chromosomes.
INHERITANCE OF ADULT PLANT RESISTANCE TO POWDERY MILDEW IN SOYBEANS
Authors: Buzzell R. I. , Haas Jerry H.
Published: November 2014

In greenhouse tests with Microsphaera diffusa Cke &Pk. on soybeans (Glycine max (L.) Merr.), adult plant resistance was found to be governed by a dominant gene, proposed as Rmd, with the recessive allele, rmd, resulting in susceptibility at all stages.
MUTATION AND DISEASE IN MAN
Authors: Neel James V.
Published: November 2014

Efforts to evaluate the burden of genetic disease maintained by mutation pressure are reviewed, Various individuals and committees have suggested that approximately 1800 per 100,000 liveborn infants will ultimately exhibit clearly defined disease due to chromosomal or point mutation. Direct estimates of human chromosomal and point mutation now permit the identification of about 370 per 100,000 liveborn infants with defect due to mutation in the preceding generation. Recent technical advances permit the study of mutation to shift to the protein level. In Amerindians, mutations resulting in electrophoretic variants of a series of proteins of the blood serum and erythrocyte occur at at rate of 1.6 × 10−3/locus/generation. While it is debatable what proportion of electrophoretic variants result in impaired health as heterozgotes or homozgotes in man, we are increasingly aware of disease due to an absence of enzyme or receptor protein due to homozygosity for "null" alleles. A conservative calculation of the possible impact of these "null" mutations on health proceeds as follows: if the rate of mutation to electrophoretic variants in man is only 1.0 × 10−5/locus/generation, and if in man the ratio of nulls to electrophoretic variants is only 2:1 rather than 5:1 of Drosophila, then null mutants with respect to protein should be 2.0 × 10−5/locus/generation. There are perhaps 5,000 proteins in man whose absence can lead to disease. It is clear we are just beginning to recognize a class of mutations whose impact on health in toto may exceed the commonly visualized gross phenotypic abnormalities. However, many of the conceptuses homozygous for these null mutations may be eliminated in utero and not come to clinical attention.
POLYMORPHISM IN THE GIEMSA C-BANDING PATTERN OF RYE CHROMOSOMES
Authors: Lelley T. , Josifek K. , Kaltsikes P. J.
Published: November 2014

Extensive polymorphism was found with regard to the presence and size of Giemsa-staining bands in the chromosomes of six inbred lines of cultivated rye (Secale cereale L.). The amount of polymorphism differed from chromosome to chromosome, with 6R being the most variable and 3R or 7R the least.
GENOME RELATIONS BETWEEN PASPALUM CONSPERSUM AND TWO DIPLOID PASPALUM SPECIES
Authors: Burson Byron L.
Published: November 2014

Paspalum conspersum Schrad. ex Schult., 2n = 4x = 40, was crossed with P. intermedium Munro ex Morong, 2n = 2x = 20, and P. jurgensii Hackel, 2n = 2x = 20, and the hybrids were studied cytologically to determine the relationship between these species. Thirteen P. intermedium × P. conspersum hybrid plants were produced; however, only eight survived. They had a chromosome number of 2n = 3x = 30. Meiosis was irregular with a chromosome pairing relationship of 19.87 univalents, 5.03 bivalents, and 0.03 trivalents per cell. These findings suggested that the two species have a partially homologous genome. The two hybrids obtained from the cross between P. jurgensii and P. conspersum had a chromosome number of 2n = 3x = 30. The mean chromosome pairing in these hybrids was 10.12 univalents. 9.86 bivalents, 0.08 trivalents, and 0.004 quadrivalents. The close bivalent pairing and a mean frequency of 9.86 bivalents suggested that the P. jurgensii genome was homologous to one genome of P. conspersum. Limited autosyndetic pairing of the P. conspersum chromosomes was also detected in both groups of hybrids. A standardization of genome formulas for the genus was proposed in which P. intermedium, P. jurgensii, and P. conspersum were represented by genome formulas of II, JJ, and I2I2 JJ, respectively. The genome relationships and formulas were discussed for other related Paspalum species.
CYTOMIXIS IN POLLEN MOTHER CELLS OF ONONIS (LEGUMINOSAE)
Authors: Morisset Pierre
Published: November 2014

Cytomixis occurred regularly in pollen mother cells (PMCs) of Ononis spinosa L., O. repens L. and O. arvensis L., from early meiotic prophase to telophase II. Usually only a few PMCs were affected in any anther, but occasionally whole anthers showed cytomictic patterns. Cytomixis generally was found at extremities but rarely in the median parts of anthers. Since it appeared to lead to the degeneration of affected PMCs or young microspores, it, therefore, could not give rise to aneuploidy. Cytomixis is interpreted as a pathological abnormality induced by pressure building up within the developing flower bud; it occurred where anthers pressed strongly against each other due to competition for space. It is suggested that uncoordinated growth rates of anthers and floral envelopes could account for intense cytomixis described in hybrids by various authors.
Q-BANDING OF CHROMOSOMES IN HUMAN SPONTANEOUS ABORTIONS
Authors: Carr David H. , Gedeon Milan M.
Published: November 2014

Chromosome studies of 242 spontaneous abortions were carried out by Q-banding technique. The abortuses were selected for study because they were phenotypically abnormal, had not progressed beyond 12 weeks development, or were from women with repeated abortions. Chromosome anomalies were found in 126 (52%) of the abortuses. Of these, 71 (56%) were trisomies. Trisomies were found for all the autosomes except Nos. 1, 3, 5, 11, 17 and 18. Triploidy was the second commonest anomaly in this series, making up 26 (21%) of the total anomalies. About 70% of these had an XXY sex chromosome complement. Only 16 (13%) of the abortuses had X monosomy, a lower frequency than would be expected in an unselected study. Tetraploidy was found in 8 abortuses and the 5 remaining specimens had various anomalies. These included 3 translocations, a trisomy 21,X monosomy and a ring chromosome 13. Except for the greater frequency of XXY than XXX sex chromosomes in the triploids, there was no evidence of a distortion of the sex ratio, either among the trisomic or among the chromosomally normal abortuses.