bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECT OF RYE ON HOMOEOLOGOUS CHROMOSOME PAIRING IN WHEAT × RYE HYBRIDS
Authors: Dvořák J.
Published: November 2014

The number of chiasmata per cell at metaphase I was scored in eight haploid plants of Triticum aestivum L. emend. Thell. cv. 'Chinese Spring' and 100 hybrid plants of Chinese Spring × Secale cereale L. Mean chiasma frequency per cell ranged from 0.00 to 3.59 in the hybrids and from 0.17 to 0.35 in the haploids. Since the same wheat genotype was present in both the haploids and hybrids, it is concluded that some of the rye genotypes promoted homoeologous chromosome pairing. The absence of distinct segregation classes among the hybrids suggests that these genes constitute a polygenic system.
GENETICS SOCIETY OF CANADA AWARD OF EXCELLENCE LECTURE AN INDUCED MUTANT WITH HOMOEOLOGOUS PAIRING IN COMMON WHEAT
Authors: Sears E. R.
Published: November 2014

An apparent deletion of Ph, the chromosome-5B suppressor of homoeologous pairing, was obtained by X-raying normal pollen and using it on plants monosomic for a 5B chromosome carrying the marker Hairy-Neck, previously transferred from rye. Of the 1278 M1 offspring, 675 were eliminated without test, because they were either 1) hairy necked and therefore possessing a maternal 5B that would have hidden any deficiencies present in the X-rayed 5B; 2) nullisomic in appearance and thus likely to have a badly damaged 5B; or 3) completely or nearly male sterile, which precluded the recovery homozygous of any mutant that might have been present. A total of 438 M1 plants were tested for pairing mutations, mostly by crossing to Triticum kotschyi and looking for increased pairing. Only one mutation was obtained that appears to be a deficiency of Ph. The homozygous mutant is somewhat reduced in vigor and fertility, and male transmission from the heterozygote was only 38.6%. A second mutation, which leads to an intermediate level of homoeologous pairing, is not located on chromosome 5B.
PLANT BREEDING EVOLVING
Authors: Rajhathy Tibor
Published: November 2014

The success of pre-Mendelian plant improvement, in spite of its intuitive, empirical and haphazard nature, is amply demonstrated by the multitude of highly adapted land races. Organized plant breeding emerged in the 18th century and made great strides in the 19th although a comprehensive theory was still lacking. Post-Mendelian plant breeding was defined and the impact of evolutionary and genetic theories was briefly examined. Breeders not only benefited from but also contributed to the Darwinian theory of evolution and were instrumental in developing the concept of quantitative inheritance of polygenic nature. The development of adapted triticale was selected as a case history for alloploid breeding and the major factors in recent success were identified. It was found that a combination of research with an extensive breeding program based on evolutionary principles was an essential element for success. Although triticale provides an illuminating model, additional ones with various genetic, breeding and developmental systems may expedite the practical utilization of de novo species. The emerging new methodology, an extension of molecular and microbial genetic methods to higher plants and tissue-culture work was outlined. These methods, when perfected, will probably remove isolation barriers to gene exchange and make the selection process vastly more effective. Some of the new methods, such as experimentally produced doubled haploids and the large scale propagation of virus-free plants via tissue-cultures, are already making an impact on the breeding of several species.
ESTERASE GENOTYPES AND PERFORMANCE TRAITS IN MEAT-TYPE CHICKENS
Authors: Grunder A. A. , Merritt E. S.
Published: November 2014

The genotypes at a serum esterase locus were determined for 3208 female meat-type chickens. These birds belonged to three generations of six strains on which records of body-weight and reproduction traits were kept. Allelic frequencies among strains were compared and then a study was made of the relationship between esterase genotype and the following traits: body weight at five ages, age at first egg, survivor egg production, rate of egg production (%), egg weight, fertility and hatchability. Allelic frequencies did not differ in two of three years between replicate control strains but were significantly different in seven of nine comparisons between selected and control strains. Analysis of variance of paired comparisons of genotypes on a within dam family basis revealed only five of the 106 comparisons to be significant. No heterotic effects were indicated. It was concluded that the esterase genotypes studied do not have a major influence on the traits investigated.
THE MEIOTIC BEHAVIOR OF ANEUPOLYHAPLOIDS OF THE CULTIVATED OATAVENA SATIVA(2n = 6x = 42)
Authors: Leggett J. M.
Published: November 2014

Chromosome pairing and the frequency of secondary associations in two aneupolyhaploid plants of A. sativa are described. There was little evidence of pairing between homoeologous chromosomes in either plant. The results are discussed in relation to the genetic control of bivalent pairing in A. sativa and the possible divergence between the constituent genomes.
CYTOGENETIC STUDIES IN NORTH AMERICAN MINNOWS (CYPRINIDAE). IV. SOMATIC POLYPLOIDY IN GILA BICOLOR
Authors: Avise John C. , Gold John R.
Published: November 2014

The kidney tissue of a single individual of the California minnow Gila bicolor (Girard) contained polyploid cells in about 1.7% frequency. Chromosome spreads of triploid, tetraploid, hexaploid, octaploid, and dodecaploid cells were observed and may have arisen through endoreduplication of ancestral diploid and triploid cells. The cytological mechanism producing the triploid cells is unknown. Diplochromosomes were not present. The distribution of ploidy in cells of this individual is not random. In particular, cells having undergone one round of chromosomal increase appear increasingly susceptible to additional rounds of chromosomal gain.
GENETIC ANALYSIS OF THE NEPHROGENIC DIABETES INSIPIDUS DEFECT IN SWV MICE
Authors: Virgo N. S. , Miller J. R.
Published: November 2014

Females of the SWV mouse strain had an age-dependent nephrogenic diabetes insipidus. The distribution of water intakes in the F1, F2 and backcross to each parental strain indicated that at least the polydipsia was determined by a few major dominant genes; rather than by a polygenic system. The Smirnof and chi square analyses revealed more than one major gene was involved. A hypothesis was presented that there are two dominant genes (one fully dominant and one codominant) which may be linked. The expression of these major genes was influenced multiplicatively by environmental factors and the water intakes approached a continuous distribution. The defect was sex influenced: SWV males had only a very mild urine concentrating defect but the reciprocal crosses showed no X-linkage. The kidney weight of the SWV females correlated significantly (P < 0.05) with the polydipsia in the F1, BC SWV and F2 progeny and the use of both traits provided a qualitative measure for classification. The polydipsia and enlarged kidneys probably represent pleiotropy.
CHROMOSOME LOCATION OF GENES CONDITIONING RESISTANCE TO CLAVICEPS PURPUREA IN SPRING AND DURUM WHEAT
Authors: Platford R. G. , Bernier C. C. , Evans L. E.
Published: November 2014

The chromosome location of genes conferring resistance to Claviceps purpurea (Fr.) Tul. in Triticum aestivum L. cv. Kenya Farmer and T. durum Desf. cv. Carleton was determined. A substitution series of individual chromosomes of Kenya Farmer into the susceptible T. aestivum cv. Chinese Spring and the F1 plants of Carleton crossed with the Chinese Spring monosomics for the A and B genomes were used. Chromosome 6B of Kenya Farmer and 1B of Carleton appeared to carry a gene or genes conditioning resistance to all three components of the resistant reaction, i.e. frequency and size of sclerotia and honeydew production. In addition, chromosome 3B of Carleton appeared to reduce the sclerotia frequency and honeydew production while several chromosomes of both Kenya Farmer and Carleton influenced sclerotia size and honeydew production.
THE GENETICS OF RESISTANCE TOPUCCINIA GRAMINIS TRITICIIN HEXAPLOID TRITICALE
Authors: Morrison R. J. , Larter E. N. , Green G. J.
Published: November 2014

The inheritance of resistance to wheat stem rust, Puccinia gaminis tritici, was studied in five hexaploid triticales (× Triticosecale Wittmack) using races C33 (15B-IL) and C17(56). Triticale lines 70HN458 and 6TA204 each possessed a single gene for seedling resistance; Rosner and MT 36-1 each carried two genes, and 6A190, three. The cultivars carried a total of at least five different dominant resistance genes. Four of these genes conditioned resistance to both rust races (C17 and C33) while a gene from line 6A190 conditioned resistance to a single race (C17 only). The seedling resistance genes also conferred resistance to adult plants while genes conferring resistance only in the adult plant stage were not detected.
GENETICS OF LEAF RUST REACTION IN THREE INTRODUCTIONS OF COMMON WHEAT
Authors: Dyck P. L.
Published: November 2014

The genetics of seedling resistance to leaf rust (Puccinia recondita Rob. ex. Desm.) was investigated in what (Triticum aestivum L.) introductions PI 268454, PI 58548 and PI 268316, originally collected in Afghanistan, China and Iran, respectively. PI 268454 was heterogeneous for resistance. A selection (PI 268454a) has a gene that confers a 1+ reaction while a second selection (PI 268454b) probably has resistance gene Lr2b. PI 58548 has two genes for resistance, one giving a 1+ reaction and the second a 2+. These two genes interact to produce a; 1 reaction. PI 268316 has three interacting genes, one giving a 1+ reaction, the second a 2+ and a third resistance gene similar to LrB. The gene giving the 1+ reaction was common to all three introductions. PI 58548 and PI 268316 carry different genes for infection type 2+. Backcross lines of the single genes were produced. Implications to breeding for disease resistance of genes interacting to produce different phenotype are discussed.
GENETICS OF WHITE-BREASTED, WHITE AND BROWN COLORS AND DESCRIPTIONS OF FEATHER PATTERNS IN JAPANESE QUAIL
Authors: Roberts C. W. , Fulton J. E. , Barnes C. R.
Published: November 2014

Genetic investigation showed that a newly arisen mutant trait, white breast feathers, was recessive, autosomal and followed a simple Mendelian pattern of inheritance when tested with the gray (Wild Type) Japanese Quail. The same results were demonstrated for a white-feathered trait. The brown-feathered trait was demonstrated to be due to a single autosomal gene which showed partial dominance. Segregation of progeny from matings between brown birds having a large patch of white feathers in the breast region indicated that the loci for brown and white were independent and that heterozygous white produced the patch phenotype in the presence of homozygous or heterozygous brown. Other feather pattern variants described were white crescent and white beard feathers, both were recessive traits and each possibly due to an effect at a single locus.
BARREN PERITHECIA INNEUROSPORA CRASSA
Authors: Raju Namboori B. , Perkins David D.
Published: November 2014

The term Barren is applied to perithecia (sexual fruiting bodies) that produce no or few ascospores. Perithecial number is usually not reduced in barren crosses. The barren condition may result from recessive or dominant mutations, from partial chromosome duplications, and occasionally from balanced chromosome rearrangements. It is characteristic of some but not all of the types of recessive genes that increase radiation sensitivity or the deletion of segmental duplication. Barrenness provides a convenient signal for these genotypes, where meiosis or ascus development is impaired. Duplications are characteristically dominant-barren, and changes from barren to fertile signal that duplicated segments have been deleted. Development has been examined cytologically in perithecia from various crosses where barrenness results from the postfertilization genotype and does not depend on the constitution of maternal tissues. Early development is often normal until it is interrupted at or just before karyogamy. In some genotypes, asci progress into prophase I and a few may reach later stages. Specific defective genotypes show characteristic differences in the time of arrest and in the pattern and details of degeneration. There is considerable overlap, however, so that precise temporal seriation is usually difficult or impractical.
GENE NUMBERS AND GENIC VARIABILITY INCIONA INTESTINALISANDBRANCHIOSTOMA LANCEOLATUM
Authors: Schmidtke J. , Kunz B. , Engel W.
Published: November 2014

The number of genes coding for various enzymes have been determined in Ciona intestinalis (Tunicata) in comparison with Branchiostoma lanceolatum (Cephalochordata) using electrophoretic methods. Both species, generally, have identical gene numbers for homologous proteins. This finding does not support the hypothesis that Branchiostoma represents an anciently polyploid step relative to Ciona. High levels of allozymic variation were observed in the two species. The data are discussed in view of the neutral mutation hypothesis.
THE SYNAPTONEMAL COMPLEX IN THE BIPARTITION DIVISION OF THE RADIOLARIAAULACANTHA SCOLYMANTHA
Authors: Lecher P.
Published: November 2014

A tripartite structure having the same morphological features (two lateral elements and a central element connected by thin threads) as synaptonemal complex, is present during a part of the bipartition division. The first appearance consists of an axial element inside each chromosome, first connected with the nuclear envelope; when the chromosomes lie side by side, two by two, the axial elements are parallel, and when close to each other, thin filaments connect them and give the typical tripartite structure; this structure persists for some time and then disaggregates giving isolated elements which persist to prometaphase. In the present case, we have no proof which allows us to interpret this kind of division as a meiotic one. We considered the synaptonemal complex observed here as a structure which exists between paired chromosomes, a structure which plays a role in a process of depolyploidisation.
SEX CHROMOSOMES IN THE SOCKEYE SALMON: A Y-AUTOSOME FUSION
Authors: Thorgaard Gary H.
Published: November 2014

Chromosomes of 21 sockeye salmon [Oncorhynchus nerka (Walbaum)] from three locations in Washington state were examined. All males had 57 chromosomes, while all females had 58 chromosomes. Both sexes had 104 chromosome arms. It appears that in males of this species the Y chromosome and an autosome have fused to form a metacentric chromosome.
INHERITANCE OF ALUMINUM TOLERANCE IN WHEAT
Authors: Lafever H. N. , Campbell L. G.
Published: November 2014

Aluminum tolerant and aluminum sensitive wheat (Triticum aestivum L. em Thell) cultivars representing different parental backgrounds were used to study the inheritance of response to aluminium. F1, F2, F3, and backcross generations from crosses of four soft red winter wheat cultivars were grown in nutrient solutions containing 8 ppm aluminum. There appeared to be no genetic differences between the two sensitive parents (Redcoat and Arthur) for aluminum response. The two tolerant parents (Seneca and Thorne) also exhibited no apparent genetic differences for aluminum response but were decidedly superior to the sensitive parents in the presence of aluminum. F1, F2, and backcross data from sensitive/tolerant crosses indicated that sensitivity was conditioned by a single recessive gene. Selection for aluminum sensitive plants in the F2 was effective, based upon their F3 family means. Selection for intermediate or tolerant plants was less effective, indicating that the inheritance was more complex than a single gene. Leaf length and roots/plant were found to be inferior to root length as measures of aluminum tolerance. These nutrient culture results were consistent with the occurrence of sensitive and intermediate lines and the absence of highly tolerant lines from breeding populations selected on limed soils.
RNA CHANGES IN ENVIRONMENTALLY INDUCED FLAX (LINUM USITATISSIMUM) GENOTROPHS
Authors: El-Gewely M. Raafat , Tyson H.
Published: November 2014

Purified samples of RNA were obtained from large (L) and small (S) flax genotrophs environmentally induced within the flax genotype Stormont Cirrus. The RNA samples were electrophoresed to separate 25S, 23S, 18S, 16S, 5S and 4S RNA's, using 2.4% and 5% acrylamide gels. Nucleotide analysis of the total RNA of each of the samples was also carried out. Differences between L and S in the relative amounts of the various RNA species were detectable. Analogous differences between L and S for the relative amounts of the four bases in the total RNA were also detectable.
HETEROCHROMATIC BANDING PATTERNS IN TWO SPECIES OF TRILLIUM
Authors: Chinnappa C. C. , Morton J. K.
Published: November 2014

Giemsa stained chromosome segments of Trillium grandiflorum (Michx.) Salisb. and T. erectum L. were compared with the heterochromatic regions (H-segments) revealed by cold treatment. Several additional C-bands which did not correspond to the H-segments were observed. The centromeric bands were different in the two species.
INHERITANCE OF A VIRESCENT TRAIT IN BROMUS INERMIS
Authors: Dunn G. M. , Lea H. Z.
Published: November 2014

The genetics of a virescent mutant was investigated in Bromus inermis Leyss. The trait was inherited as a single, tetrasomic recessive. Selfing the original mutant resulted in 4755 virescent:21 green seedlings when grown at 15 °C. From the data it was concluded that the mutant was homozygous for the virescent gene and that the occasional green, selfed seedlings probably arose by outcrossing.
THE EFFICIENCY OF USING DOUBLED HAPLOIDS IN A RECURRENT SELECTION PROGRAM IN A DIPLOID, CROSS-FERTILIZED SPECIES
Authors: Choo T. M. , Kannenberg L. W.
Published: November 2014

Mass selection in both doubled haploid and diploid populations was simulated for a 30-year period under additive and complete dominance models. The response to S1 selection was also included for the purpose of comparison. All selection programs were conducted at two selection intensities, 5% and 25%, under 0.2 heritability with a constant population size of 400. S1 lines were evaluated in 10-plant plots with four replications; use of a winter nursery was assumed. The character under selection was controlled by 20 major (A = 2) genes and 20 minor (A = 1) genes. The initial frequency of ten of the major genes and ten of the minor genes was 0.5; that of the remaining ten of each type was 0.1. The response to mass selection with doubled haploids was about 1.4 times faster than diploid mass selection and equal to S1 selection in terms of gain per year. If replicated trials were used to evaluate the doubled haploids, the rate of gain was faster than in S1 selection. The greater efficiency of using doubled haploids was due to doubling of the additive genetic variance and the elimination of dominance variance. However, significant loss of desirable genes occurred in the mass selected doubled haploid population under both the 5% and 25% selection intensities in the additive and complete dominance models.
MODIFICATION OF THE COLCHICINE TECHNIQUE FOR CHROMOSOME DOUBLING OF BARLEY HAPLOIDS
Authors: Thiebaut J. , Kasha K. J.
Published: November 2014

Haploid barley plants, produced from the interspecific cross of barley (Hordeum vulgare) by H. bulbosum, were used to evaluate modifications of colchicine treatments for improved chromosome doubling. Plants were treated at the 3-leaf stage in culture vials. With the addition of Tween 20 (a wetting agent) to colchicine – DMSO solutions, the percentage of surviving plants with doubled sectors was 54% compared to 33% for controls; however, plant survival decreased from 93% to 73%. The further addition of 10 mg/1 GA3to the treatment solution showed an increase from 54% to 72% plants with doubled sectors and a plant survival of 83%. The extent of doubling per plant as measured by the percentages of spikes and florets with seed increased in the presence of Tween 20 but was reduced when GA3was included in the treatment solution. Cytological examination of diploid barley root-tips treated with colchicine, colchicine plus DSMO, and colchicine plus DMSO plus GA3revealed a quicker recovery from C-metaphase in the presence of GA3. However, no difference in either the mitotic index or frequency of tetraploid cells was observed.
EFFECT OF THE REMOVAL OF GENES PROMOTING HOMOEOLOGOUS CHROMOSOME PAIRING ON CHROMOSOME PAIRING IN TRITICUM AESTIVUM × TRITICUM URARTU AMPHIPLOIDS
Authors: Dvořák J.
Published: November 2014

Chromosome pairing in Triticum aestivum cv. Chinese Spring × T. urartu hybrids lacking chromosome arm 5AS or 5BS was shown to be lower than in similar hybrids involving euploid Chinese Spring. Amphiploids were produced from crosses of Chinese Spring, ditelosomic 5AL, and ditelosomic 5BL with a specific strain of T. urartu. The absence of asynapsis in the amphiploids lacking chromosome arm 5AS or 5BS provides evidence that the poor chromosome pairing observed in the corresponding F1 hybrids was due to suppression of homoeologous pairing and not to general asynapsis. This conclusion is supported by the finding that heterogenetic chromosome pairing, as evidenced by the frequency of multivalents, was lower in the ditelo 5BL × T. urartu amphiploids than in the amphiploids from the cross Chinese Spring × T. urartu.
THE EFFECTS OFLAOON ALDEHYDE OXIDASE ACTIVITY AND CROSS-REACTING-MATERIAL INDROSOPHILA MELANOGASTER
Authors: Williamson John H. , Bentley Michael M. , Oliver Melvin J. , Geer Billy W.
Published: November 2014

In Drosophila melanogaster aldehyde oxidase occurs in at least two forms that can be separated electrophoretically. The mutant allele lao (low aldehyde oxidase activity) causes a deficiency of the major form of this enzyme. Immunoelectrophoretic analyses suggest that lao homozygotes produce aldehyde oxidase cross-reacting-material in nearly wild-type levels. Although aldehyde oxidase from the mutant stock is heat labile, properties such as Kmand pH optima are not different from the normal enzyme.
CORRELATIONS BETWEEN CHROMOSOME SEGMENTS AND FITNESS INDROSOPHILA MELANOGASTER III. DIFFERENTIAL GENETIC RESPONSES TO ZINC SULFATE AND SELENOCYSTINE
Authors: Chapco W. , Jones S. G. , McConnell W. B.
Published: November 2014

Genetic × environmental interactions are examined at an intrachromosomal level in Drosophila melanogaster. With respect to two fitness components, egg production and egg-to-adult viability, evidence is provided that different segments of the X chromosome are affected differently by each of the chemical substances, zinc sulfate and selenocystine. The extent of a segment's effect on a trait is not always parallelled by the extent of its association with that trait's sensitivity to chemical treatment. Both attributes are functions of the genetical background. The degree of dominance of each segment is not always greater in the chemical environments, a finding inconsistent with Parson's concept of "extreme-environment heterosis."
LATERAL ELEMENT CROSS CONNECTIONS OF THE SYNAPTONEMAL COMPLEX AND THEIR RELATIONSHIP TO CHIASMATA IN RAT SPERMATOCYTES
Authors: Moens Peter B.
Published: November 2014

Observations are presented in support of the hypothesis that at meiotic prophase a reciprocal crossover is accompanied by a crossover of the lateral elements of the synaptonemal complex, SC (Moens, 1974). Rat spermatocyte nuclei in developmental stage VII (Clermont, 1972) of the seminiferous epithelium cycle, but not pachytene nuclei in stages I to VI, were found to have SC modifications in the form of a cross connection between the lateral elements. In structure these crossover elements, CO elements, resemble the lateral element. It is found in a variety of positions, usually more or less perpendicular to the SC but also slanted or parallel along the central element or detached from the SC. Reconstructions of entire nuclei indicate an average of one such CO element per SC and a nonrandom distribution of CO elements among the SCs. Because the crossing-over of lateral elements produces a 180° twist or removes a 180° twist, the pattern of SC coiling was examined. Coiling starts in early pachytene prior to CO element formation. At stage VII one nucleus had a total of 78 coils, all counter clockwise, and another nucleus had 97 such 180° coils. It is noted that if SC coils are associated with the process of crossing-over, then the regulation of crossover distribution such as chiasma position interference has an explanation in the structure and behavior of the SC.
YCHROMOSOME HYPERPLOIDY AND MALE FERTILITY INDROSOPHILA MELANOGASTER
Authors: Williamson John H. , Meidinger Eva
Published: November 2014

Drosophila melanogaster males with two supernumerary Y chromosomes, i.e. triplo-Y males, are completely sterile. Their mating behavior is normal, and spermatogenesis and spermiogenesis appear normal, but no sperm are transferred. Most, if not all, of the detrimental effects of a third Y chromosome on male fertility are attributable to the long arm of the Y chromosome.
GLUTAMATE-OXALOACÉTATE TRANSAMINASE ET α-GLYCÉROPHOSPHATE DÉSHYDROGÉNASE CHEZ LE MOUSTIQUE AEDES (OCHLEROTATUS) CASPIUS: GÉNÉITIQUE FORMELLE ET ÉTUDE DE POPULATIONS
Authors: Mery André , Pasteur Nicole , Guilvard Eliane
Published: November 2014

In Aedes caspius (Pallas) the α-Gpd locus, coding an α-glycerophosphate dehydrogenase, has three codominant alleles and is localized on the sex chromosome at about one unit of crossing-over from the sex factor. The Got-1 locus, coding a glutamate-oxaloacetate transaminase has four codominant alleles and is autosomal. The study of nine populations collected in France, Tunisia and Morocco demonstrates a low level of polymorphism at the α-Gpd locus (heterozygosity of 0.065 per population) and a high polymorphism at the Got-1 locus (heterozygosity of 0.496 per population). Got-1 polymorphism of A. caspius is compared with that of the two A. detritus sibling species that segregate for alleles with the same electrophoretic mobility, and colonized the same sites.
MEIOTIC STABILITY IN CONTROL AND NEWLY COLCHICINE-INDUCED DIHAPLOID BARLEY
Authors: Finch R. A. , Bennett M. D.
Published: November 2014

Comparison of meiosis in barley plants treated with colchicine when seedling or juvenile haploids and in control dihaploids similarly treated two generations earlier shows that colchicine used to double the chromosome number of barley haploids has no effect on meiosis which could lead to difficulties in screening breeding material.
INVITATION PAPER: CAN MUTATION THEORIES OF CARCINOGENESIS SET PRIORITIES FOR CARCINOGEN TESTING PROGRAMS?
Authors: Stich H. F. , Acton A. B.
Published: November 2014

The recent activity in designing, validating and implementing short-term tests for carcinogens has been spurred by the fairly convincing correlation between the carcinogenicity and mutagenicity of chemicals and by the assumption that mutations are somehow involved in neoplastic transformation. Moreover, it has been tacitly assumed that the mutagenic capacity alone of compounds would induce regulatory agencies to pass rules for their removal from man's environment, and would lead the public to avoid them. The actual response, however, is quite different. Governmental departments shy away from making any decisions on the basis of in vitro test systems, the public at large is becoming irritated by daily announcements that many of their cherished habits could adversely affect their health, and industries feel threatened and may reduce their search for new beneficial chemicals. The reluctance to accept wholeheartedly the mutagenicity tests for the detection of carcinogens is partly due to the uncertainty about the involvement of mutations in the formation of benign and malignant tumors. Following the initial rapid advances in the detection of environmental chemicals with carcinogenic and mutagenic properties, we seem to have arrived at the cross roads: we must now set new priorities for future research, and must make an unbiased assessment of the actual hazard of a compound to man and the human population.
KARYOLOGY OF FOUR NORTH AMERICAN PERCIDS (PERCIFORMES: PERCIDAE)
Authors: Gold J. R. , Janak B. J. , Barlow Jr. J. A.
Published: November 2014

We have examined the chromosomes of four darter species (Percidae) from Texas and Louisiana: Percina caprodes, P. nigrofasciata, P. sciera and Ammocrypta vivax. All four have diploid complements of 48 chromosomes. Estimates of diploid chromosome arm number among the four species varied from 80 (P. sciera) to 92 (P. caprodes and A. vivax) to 94 (P. nigrofasciata); but between two to five chromosome pairs in each species could not be unequivocally classified as either uni-armed or bi-armed. Percina sciera, which was scored as having the highest number (16) of uni-armed chromosomes, probably differs in gross karyotype from the other three, but the magnitude of difference may be less than indicated by our measurements.
METAPHASE I PAIRING FREQUENCIES OF INDIVIDUALAGROPYRON ELONGATUMCHROMOSOME ARMS WITHTRITICUMCHROMOSOMES
Authors: Dvořák J.
Published: November 2014

Ten telocentric chromosomes of diploid Agropyron elongatum (Host.) P.B. (2n = 14) were added to the chromosome complement of Triticum aestivum L. emend. Thell. The ditelosomic additions were crossed with Triticum speltoides (Tausch) Gren. ex Richter, and in the tetraploid hybrids the pairing frequencies of the telosomes were determined, expressed as percent of PMC's in which a telosome paired at metaphase I. All Agropyron telosomes paired with Triticum chromosomes. The pairing frequencies ranged from 4.4% to 41.2% of the PMC's, it is concluded that none of the ten Agropyron chromosome arms has a homologous partner among the four Triticum genomes involved. The pairing frequencies did not correlate with the lengths of the telosomes. Pairing of the Agropyron telosomes in these tetraploid hybrids approximated the chromosome pairing that occurred in a diploid hybrid T. tauschii (Coss.) Schmal. (the donor of the D genome of T. aestivum) × A. elongatum.
ANALYSIS OF DOSE-RESPONSE PATTERNS IN MUTATION RESEARCH
Authors: Haynes R. H. , Eckardt Friederike
Published: November 2014

Mutation induction data in unicellular systems can be described mathematically within the framework of single-event Poisson statistics. This formal description can be linked to various mechanistic models for mutation and killing. Such mathematical links between formalism and mechanism enable one to make use of the quantitative details of dose-response relations in drawing general inferences regarding the macromolecular processes involved in mutation and killing. Mutation yields, and in particular the position and magnitude of maximum yields, should be measured as carefully as possible as a means of verifying the apparent pattern of mutation induction kinetics suggested by double-logarithmic plots of mutation frequencies. For purely linear processes of mutation induction and exponential survival the maximum mutant yield is known to occur at the LD37dose; however for non-linear kinetic patterns, the position and magnitude of the maximum yield shifts away from the LD37in mathematically predictable ways. For any given pattern of killing and mutation, the ratio of the maximum mutant yields plotted over lethal hit units for two mutagens is a convenient measure of their relative mutagenic efficiencies.
GENOMES OF THE AUSTRALIAN WILD SPECIES OF COTTON. I.GOSSYPIUM STURTIANUM, THE STANDARD FOR THE C GENOME
Authors: Edwards G. Allan
Published: November 2014

A detailed karyotype of Gossypium sturtianum Willis is presented to establish the C genome karyotype for comparison with other Australian wild species of cotton. Gossypium sturtianum has one chromosome with a median centromere, eight with slightly submedian centromeres, two with submedian centromeres and two with highly submedian centromeres. Chromosomes 8 and 9 have satellites. The total complement length is 75.04 micrometers.
DIFFERENTIAL GIEMSA STAINING IN PLANTS. VI. CENTROMERIC BANDING
Authors: Filion W. Gary , Blakey David H.
Published: November 2014

Somatic metaphase chromosomes of Tulipa which were subjected to various hydrolyses with several times and temperatures displayed two distinctive types of C-banding when stained using the BSG (Barium hydroxide/Saline/Giemsa) chromosome banding technique. In addition to the two types of Giemsa bands, namely intercalary/terminal and centromeric, a unique transition from the former to the latter type of banding was observed. That is, at the point of transition from intercalary/terminal to centromeric banding, both types were present at one time. The two types of Giemsa banding resulted from different HCl hydrolysis times and temperatures; centromeric bands being observed after either a prolonged hydrolysis at room temperature or an increase in the hydrolysis temperature to 60 °C. These results are discussed in relation to the mechanisms of chromosome banding.
AN ANALYSIS OF XANTHINE DEHYDROGENASE NEGATIVE MUTANTS OF THEROSYLOCUS INDROSOPHILA MELANOGASTER
Authors: Girton Lois E. , Lo Reggie Y. C. , Bell John B.
Published: November 2014

Eighteen alleles of the rosy locus in Drosophila melanogaster were characterized to identify putative nonsense mutants. Seven alleles exhibited no evidence of intragenic complementation, no evidence of immunological cross-reactivity to antibodies elicited by wild type xanthine dehydrogenase (XDH), and of course were completely deficient in measurable XDH activity. It is possible that one or more of these highly negative ry alleles are nonsense mutants. The remaining eleven ry alleles code for XDH molecules that retain some antigenic similarities to the wild type enzyme as assessed by immunoelectrophoresis and six of these eleven were capable of intragenic complementation.
ANALYSIS OF SELECTION PROCESSES USING THE INCOMPLETELY-PENETRANT MUTANTeuOFTRIBOLIUM CASTANEUM
Authors: Wool David , Bergerson Orna
Published: November 2014

Two genetic markers were followed for ten generations in one hybrid and two control populations of the flour beetle Tribolium castaneum (Herbst). The incompletely-penetrant eu changes the number of terminal appendages in the larva and the pupa (urogomphi) from the normal 2 to 3 or 4, and the semi-dominant b changes the body color from brown to black in adult beetles. Three simultaneous selective processes were discovered. There was strong selection against eu, mainly through lowered eu/eu adult fecundity and zygote mortality. Selection against genes linked to b may have caused its decline from 50 to 40% in ten generations. Egg to adult survival increased considerably in all three populations, apparently due to selection for improved fertility at 25 °C imposed by the experimental regime.
EXPRESSION OF VERNALIZATION GENES IN NEAR-ISOGENIC WHEAT LINES: METHODS OF VERNALIZATION
Authors: Salisbury P. A. , Berry G. J. , Halloran G. M.
Published: November 2014

Four near isogenic lines of wheat (Triticum aestivum L. em Thell.) were given various combinations of vernalization as imbibed seed and as growing plants. The combinations were designed so that all treatments had the equivalent of four weeks at 4 °C. In terms of days to anthesis the lines reacted in three different ways to increases in the proportion of the vernalization treatment given to the growing plant. Two lines exhibited a threshold response, another showed a graded response, while the remaining line was unaffected by the method of vernalization. The treatments affected final leaf number differently, and the usually strong positive correlation with days to anthesis was not evident. Similarly there was no evidence of a relationship between days to anthesis and spikelet number. The rate of reproductive development of varieties vernalized as imbibed seed will not necessarily reflect their development rate when vernalized naturally in the field. Hence wheat breeders adapting varieties to particular environments by the use of vernalization genes should evaluate their action under appropriate field conditions.
REPRODUCTIVE BEHAVIOR OF SOYBEAN HAPLOIDS CARRYING THEMS1ALLELE
Authors: Sorrells M. E. , Bingham E. T.
Published: November 2014

Ten maternal haploids (2n = 20) of soybean (Glycine max (L.) Merr.) obtained among twin progeny of ms1/ms1plants were crossed with normal diploids (2n = 40) and the F1plants were analyzed cytologically in a search for aneuploids. A total of 67 F1seed lines from 10 haploids were analyzed cytologically. These progenies consisted of 52 diploids (2n = 40), one triploid (2n = 60), nine tetraploids (2n = 80), one 70-chromosome plant, and four trisomics (2n = 41). The predominance of diploids in the progeny of haploid × diploid crosses suggests that the ms1allele in the haploids enhanced production of restitution female gametes. Trisomics were similar morphologically to their diploid sibs, although the number of seeds per plant and the number of seeds per pod were slightly reduced. The extra chromosome was transmitted with a frequency of about 30% among a progeny of 20 plants from each of two self-pollinated trisomics and 60% among a progeny of 20 plants from another self-pollinated trisomic. It is possible that the restitution-gamete production associated with the ms1allele carried by the haploids reduced the efficiency of isolating aneuploids.
RELATION BETWEEN CELL CYCLE AND YIELD OF ABERRATIONS OBSERVED IN IRRADIATED HUMAN LYMPHOCYTES
Authors: Leonard A. , Decat G.
Published: November 2014

The bromodeoxyuridine-Giemsa technique has been used to study systematically the incidence of cells in first or subsequent mitoses at different fixation times of human lymphocyte control cultures as well as the influence of ionizing radiations on cell kinetics. Second divisions appear (3%) in cultures harvested 48 h after initiation. In 72 h cultures 40% of the dividing cells are in second and 33% in third division. Administration of 200 rads of X-rays before PHA stimulation results in a mitotic delay but does not increase the incidence of SCE. The yield of dicentrics after an exposure to 200 rads was the same for all cells in first mitosis regardless of fixation time. These results demonstrate that there is no evidence for the existence of sensitive subpopulations that could be distinguished by the time of the first mitotic division following stimulation.
MONOSOMES AND TELOSOMES FOR 18 OF THE 26 CHROMOSOMES OFGOSSYPIUM HIRSUTUM
Authors: Endrizzi J. E. , Ramsay G.
Published: November 2014

Monosomes and/or telosomes for 18 of the 26 chromosomes of cultivated cotton, Gossypium hirsutum L., are listed along with the major plant characters which distinguish monosomics and monotelodisomics from normal sib plants.
RIBONUCLEOPROTEIN STAINING OF LUZULA KINETOCHORES
Authors: Braselton James P.
Published: November 2014

When mitotic chromosomes of Luzula purpurea Link, are stained for ribonucleoprotein with the uranyl acetate-EDTA-lead citrate procedure, kinetochores appear as electron-opaque regions within recesses on the chromosomes.
EXPRESSION IN DIPLOIDS OF THE MUTATOR PHENOTYPE OF SOME MUTATOR MUTANTS OFSACCHAROMYCES CEREVISIAE
Authors: Morrison D. P. , Quah Siew-Keen , Hastings P. J.
Published: November 2014

The mutator mutants of yeast, mut3-1, mut3-2 and mut4-1, are much less clearly expressed in diploids than in haploids, but the mutator phenotypes of mut3-1 and mut4-1 are restored when the diploids are made homozygous for the a mating type. An allele of RAD51, mut5-1, is expressed in a/a diploids to the same extent as in a/a diploids. Since a mutation of RAD51 causes loss of the a/α recombination repair after λ-irradiation, it is concluded that these two a/α effects are expressions of the same mechanism and that, therefore, mut3, mut4 and mut5 all owe their high spontaneous mutation rate to changes in the repair of spontaneous lesions in DNA. It is noted that, in the absence of a/α repair, the spontaneous mutation rate per cell in a diploid is the same as, rather than twice, that in a haploid.
PORCINE (SUS SCROFA DOMESTICA) CHROMOSOME IDENTIFICATION AND SUGGESTED NOMENCLATURE
Authors: Lin C. C. , Biederman B. M. , Jamro Heidi K. , Hawthorne A. B. , Church R. B.
Published: November 2014

Various banding techniques have been used for chromosome analysis in domestic pigs (Sus scrofa domestica). The techniques used in karyotype analysis were Q-banding by (CMA)2S, trypsin-G-banding, BrdU-Acridine-Orange R-Banding and C-banding. Sequential staining techniques of quinacrine-Giemsa were used to record the length of each chromosome and determine arm ratios. Sequential Quinacrine-Giemsa-Ag-AS treatment was used to locate the nucleolar organizer (NOR) on specific chromosomes. A G-C specific fluorochrome was used for reverse fluorescent banding and to differentiate certain chromosome regions which may contain G+C rich DNA. Unequivocal identification of all individual autosomes and sex-chromosomes in the porcine complement is now possible. The X-chromosome of the species has a banding pattern similar to the human X-chromosome. A nomenclature system similar to that used for human chromosomes is proposed for the G-banded and Q-banded karyotype of the domestic pig. The results of C-banding and olivomycin fluorescent banding suggest that at least three types of heterochromatin are contained in the porcine genome.
PERFORMANCE OF CROSSES OF SELECTED LINES OFTRIBOLIUM CASTANEUM
Authors: Jui P. Y. , Friars G. W.
Published: November 2014

Data from diallel crosses of seleced lines of Tribolium castaneum (Herbst) with various degrees of inbreeding were analysed to determine the breeding potential of the selected lines for general combining ability (g.c.a.) and specific combining ability (s.c.a.). Crosses of lines selected for high pupa weight did not restore the losses of pupal weight due to inbreeding. In the downward selected lines, a reversal of inbreeding depression at five levels of inbreeding (0.12 < F < 0.79) was observed only among crosses of minimal inbreeding lines. G.c.a. effects were more often significant than those of s.c.a. which were significant only in crosses of full sib lines.
RELATIONSHIP OF TAXA IN MEDICAGO AS REVEALED BY HYBRIDIZATION. IX. M. TURBINATA × M. TRUNCATULA
Authors: Lesins K. , Dickson Judy , Ostafichuk Lisa
Published: November 2014

Two taxa, one supposedly Medicago turbinata (L.) All., the other M. truncatula Gaertn., were somewhat similar in morphology. Hybridization was successful; the F1 plants obtained were completely sterile with no fully developed pollen grains. At MI various abnormalities were found, although occasionally a complete set of eight bivalents was seen. The F1 plants were somewhat chlorophyll deficient, though viable in the greenhouse. It was concluded that the two taxa belonged indeed to the two designated species. After chromosome doubling, fertility in F1 plants was induced. Reasons for differences in fertility induction after chromosome doubling are discussed along with other findings in Medicago hybrids.
GENETIC ANALYSIS OF QUANTITATIVE CHARACTERS IN CIGAR AND PIPE TOBACCONICOTIANA TABACUM. I. MORPHOLOGICAL CHARACTERS
Authors: Ogilvie I. S. , Kozumplik V.
Published: November 2014

A diallel cross of four cigar and one pipe tobacco was analysed for the following characters: (1) height before topping (2) height after topping (3) number of leaves (4) leaf width (5) leaf length (6) leaf angle and (7) days from transplanting to flower. The experiment was performed over three years with four replications. Analysis was done for general combining ability and specific combining ability. General combining ability was in all cases greater than specific combining ability, although there were some specific combining ability effects. The line Pennbel 69 showed very high positive general combining abilities for all characters while the line Petit Havane showed negative general combining abilities for these characters. Commercial production of F1hybrids would not seem to be of any advantage for any of these characters with these parental lines.
CYTOPLASMIC HOMOLOGY BETWEEN AEGILOPS TRIUNCIALIS AND AE. UMBELLULATA
Authors: Maan S. S.
Published: November 2014

The Triticum aestivum L. (2n = 42; AABBDD) and T. durum Desf. (2n = 28; AABB) genomes were substituted into the cytoplasm of two Aegilops triuncialis L. (2n = 28; CCCuCu) accessions. In F1 (ABCCu) and in a 42-chromosome backcross plant (AABBCCu) meiotic pairing between the C- and Cu-genome chromosomes was substantially reduced. Therefore, some of the pairing in the F1 of Ae. caudata L. (2n = 14; CC) × Ae. umbellulata Zhuk. (2n = 14; CuCu) may have been of the homoelogous type. In early backcrosses with T. aestivum, the euploid gametes or zygotes did not function in plants having Aegilops chromosome(s), but euploid plants with Ae. triuncialis cytoplasm were obtained in the fifth backcross. These plants were used as the cytoplasmic source to substitute the T. durum genomes into Ae. triuncialis cytoplasm; euploid durum plants were obtained in the second backcross. Alloplasmic T. durum and T. aestivum plants with Ae. triuncialis cytoplasm had closer resemblance to the plants with Ae. umbellulata cytoplasm than to those with Ae. caudata cytoplasm. These nucleo-cytoplasmic interactions indicated cytoplasmic similarity between Ae. umbellulata and Ae. triuncialis.
GENETIC CONTROL OF RESISTANCE IN TOMATO (LYCOPERSICON ESCULENTUM). II. SEGREGATIONS FOR HIGH AND LOW LEVELS OF RESISTANCE TO MELOIDOGYNE INCOGNITA
Authors: Sidhu Gurmel S. , Webster John M.
Published: November 2014

Tomato cultivars Nematex and Rutgers show different levels of resistance to root-knot nematode Meloidogyne incognita (Kofoid and White) infection. A method based on the number of galls per unit length of root is used to determine the low and high levels of resistance, and, based on this, the mode of inheritance of such resistance levels. High level of resistance of cv. Nematex is controlled by the resistance gene LMiR1 and the low level of resistance of cv. Rutgers by its allele [Formula: see text].
MULTIVARIATE ANALYSES OF POTATO HYBRIDS. I. DISCRIMINATION BETWEEN TETRAPLOID-DIPLOID HYBRID FAMILIES AND THEIR RELATIONSHIP TO CULTIVARS
Authors: Tai G. C. C. , Jong H. De
Published: November 2014

Clones of ten 4x-2x hybrid families were obtained by crossing five Group Tuberosum parents with each of two (Group Phureja × haploid Group Tuberosum) parents. The performances of horticultural traits of the 4x-2x progenies were distinctly different from those of the 4x parents and cultivars. Multivariate analyses of eight traits were performed on data of each of the three field trials in 1976, 1977 and 1978 and on the means of clones over the three years. Multivariate analyses of variance indicated significant differences between mean vectors of the 4x-2x families. Canonical analysis based on means of clones revealed clearly the effects of 4x and 2x parents on the distributions of the 4x-2x families. However, analysis of canonical distances between the hybrid families also suggested the possible existence of interactions of 4x and 2x parents. Substantial distance was observed between the 4x-2x families and the 4x parents and cultivars. The results lead to a discussion on future strategies of using the 4x-2x hybrids in potato breeding.