bluuebunny/crossref_metadata_2025 huggingface dataset:
TWO-WAY SELECTION ON PUPAL WEIGHT WITH DIFFERENT DEGREES OF INBREEDING IN TRIBOLIUM CASTANEUM
Authors: Jui P. Y. , Friars G. W.
Published: November 2014

Responses to selection for high and low pupal weight in Tribolium castaneum under four different inbreeding systems and two different relative humidities (40 and 70%) were observed for seven generations. By the seventh generation, the coefficients of inbreeding ranged from 0.79 in the full sib lines to 0.12 in the control lines.Heritability of pupal weight estimated by mid-parent offspring regression from the base population was around 0.30 which is lower than the estimates obtained by Bell (1969). However, realized heritabilities were around 0.50. Significant progress was observed for both upward and downward selection. A linear response in pupal weight was observed for most of the selected lines, suggesting that the selection limit had not been reached.Inbreeding caused a reduction of approximately two offspring per 10% increment in the inbreeding coefficient.Asymmetric responses were noted in conjunction with the significant interaction of the degree of inbreeding and the direction of selection.
THE EFFECT OFsulON PERMISSIVENESS OF PlkcIN STRAIN B OFESCHERICHIA COLI
Authors: Chung Young S. , Greenberg Joseph , Donch John
Published: November 2014

Strain B/r (Witkin) of Escherichia coli unlike strain B is permissive for the growth of Plkc. All 485 radiation resistant (sul) mutants of strain B, selected from among survivors of ultraviolet radiation or methylmethane sulfonate were permissive for Plkc. Permissiveness for Plkc followed the sul marker when transferred into strain B by sexual recombination or Pl transduction. Though sul is known to suppress some of the properties of lon, the gene associated with UV sensitivity and filamentation in strain B, lon, itself was found not to be involved in permissiveness for Plkc. Thus lon mutants of strain K12 were and lon+derivatives of strain B were not necessarily permissive for Plkc. A gene, not lon+, could be transferred from K12 to strain B by sexual recombination which conferred permissiveness for Plkc on the recipients. This gene maps between leu and proA. It's relationship to sul+is discussed.
THE LOCATION OF THE POSITIONS OF THE BREAKPOINTS INVOLVED IN THE T26H AND T70H MOUSE TRANSLOCATIONS WITH THE AID OF GIEMSA-BANDING
Authors: Boer P. de , Gijsen M. van
Published: November 2014

The positions of the breakpoints involved in the T(2;8)26H and T(1;13)70H mouse translocations have been located to specific minor bands using a trypsin-Giemsa banding method and a nomenclature system for band patterns as developed by Nesbitt and Francke (1973). The breakpoint positions are 2H1 and 8A4 for T26H and 1A4 and 13D1 for T70H. The interstitial segments occupy 80.9% of chromosome 2, 30.1% of chromosome 8, 14.4% of chromosome 1 and 88.0% of chromosome 13. It is concluded that the variation of the location of the breakpoint positions is mainly caused by differential chromosome contraction and measuring errors and only to a small extent by the resolving power of the G-banding technique.
THE PRODUCTION OF A DDT-RESISTANT STRAIN OF AEDES AEGYPTI MARKED ON ALL THREE LINKAGE GROUPS
Authors: Margham J. P. , Wood R. J.
Published: November 2014

DDT-resistant strains marked on all three linkage groups have been produced by selection at the adult stage after outcrossing a resistant strain (BANGKOK-HR) to a marked susceptible strain (64). The most resistant and viable line (BANGKOK-MR) was kept for linkage studies. The production of a marked resistant strain was not entirely straightforward. In the absence of a suitable genetic background, major resistance genes conferred little or no DDT tolerance and could not be selected. Selection at the adult stage produced resistance in larvae as well as in adults. Resistance was achieved more rapidly in larvae than in adults
CHROMOSOME RELATIONSHIPS BETWEEN AVENA SATIVA AND THE TWO DIPLOID SPECIES A. CANARIENSIS AND A. PROSTRATA
Authors: Thomas Hugh , Leggett J. M.
Published: November 2014

Although the diploid species Avena canariensis has a number of morphological features in common with the hexaploid species of Avena, the degree of chromosome pairing in the tetraploid hybrid A. canariensis × A. sativa did not reveal closer homology with A. sativa than that of another diploid species, A. prostrata. The chromosomes of both these newly described diploid species are only partially homologous with one of the genomes of A. sativa. The two diploid species A. prostrata and A. canariensis are differentiated by translocations involving three pairs of chromosomes.
QUINACRINE FLUORESCENCE AND Q-BANDING PATTERNS OF HUMAN CHROMOSOMES.: I. Effects of Varying Factors
Authors: Lin C. C. , Sande H. van de , Smink W. K. , Newton D. R.
Published: November 2014

Various factors involved in the production of "Q-bands" have been studied. It was found that a Zeiss standard WL fluorescent microscope required a shorter exposure time for photography as compared to a Zeiss photomicroscope. The minimal exposure time was obtained when the standard WL microscope was equipped with a UV light source containing a DC powered mercury burner and a concave mirror. Further, the pH and type of water used in the staining, washing and mounting of the slide were also important factors in producing clear and well differentiated "Q-bands". It also appears that the factors involved in the production of "Q-bands" effect the enhancement or quenching of fluorescence by poly d(A-T).poly d(A-T) and salmon sperm DNA or poly dG∙poly dC respectively. This preliminary report also suggests that DNA or polynucleotides with a specific base sequence may play an important role in Q-banding patterns on chromosomes.
KARYOTYPIC CHANGES AND SELECTION PRESSURE IN HAPLOPAPPUS GRACILIS SUSPENSION CULTURES
Authors: Singh B. D. , Harvey B. L. , Kao K. N. , Miller R. A.
Published: November 2014

Two cell lines with 6 and 16 chromosomes were obtained from a predominantly diploid (4-chromosome line) suspension culture of Haplopappus gracilis (Nutt.) Gray. Selection was found to be 'conservative' in the 4- and the 6-chromosome line, while it was 'progressive' in the 16-chromosome line. Mitotic abnormalities and chromosomal aberrations were most frequent in the 16-chromosome line and least frequent in the 4-chromosome line.When grown in mixtures the frequency of one line increased while the other line or lines were rapidly eliminated. The 4-chromosome line showed the highest fitness. It was concluded that the 6- and/or the 16-chromosome lines were eliminated from mixtures due to slower growth rates.
CONFIRMATION OF THE IDENTIFICATION OF THE RYE CHROMOSOME IN 1B/1R WHEAT-RYE CHROMOSOME SUBSTITUTION AND TRANSLOCATION LINES
Authors: Bennett M. D. , Smith J. B.
Published: November 2014

Chromosome 1R is readily distinguished from all other rye chromosomes and from all the chromosomes of hexaploid wheat in both Giemsa stained root-tip metaphase cells and in Feulgen stained antipodal cells with highly endopolyploid nuclei. Studies of these cells, stained using the appropriate methods, show that the two varieties 'Weique' and 'Neuzucht' both contain a single pair of alien substituted chromosomes and confirm their identity as chromosome 1R. It is also shown that the two varieties 'Aurora' and 'Kavkaz' both possess a single pair of wheat-rye translocation chromosomes which contain at least the major part of the short arm of chromosome 1R.
FERTILITY AND MEIOTIC BEHAVIOUR IN TETRAPLOID BARLEY
Authors: Fedak George
Published: November 2014

Chromosome pairing at metaphase I and distribution at anaphase I were examined in 3 autotetraploid and 3 amphidiploid parents and their F1hybrids and related to spike fertility of the respective plants. Structural differences translocated from the Hordeum leporinum chromosomes to H. vulgare did not significantly enhance preferential pairing and subsequent fertility in the latter as anticipated. Quadrivalent formation was not related but regular disjunction at anaphase I was related to spike fertility.
ELECTROPHORETICALLY DETECTABLE HETEROZYGOSITY IN A FINITE POPULATION
Authors: Marshall D. R. , Brown A. H. D.
Published: November 2014

The level of heterozygosity expected in a finite population for electrophoretically detectable alleles which are neutral to selection is calculated by a new procedure. First, the expected proportion of heterozygotes which differ by k nucleotide substitutions is shown to be a geometric distribution with parameter f (= [4Neu + 1]−1). Next, the probability of electrophoretic identity of proteins differing by k substitutions is calculated for the single-step mutation model of Ohta and Kimura. Finally, these two results are combined to confirm Ohta and Kimura's formula for electrophoretically detectable heterozygosity. These calculations indicate that the effective number of electrophoretic alleles is far less sensitive to changes in population size or mutation rate than the total effective alleles.
COMPARISON OF MORPHOLOGY OF LEAVES FROM NORMAL, CYTOPLASMIC MALE–STERILE AND RESTORED VERSIONS OF ZEA MAYS
Authors: Sarvella Patricia , Grogan C. O. , Myhre D. L.
Published: November 2014

Leaf thickness, number of trichomes, number and size of stomatal and epidermal cells were compared in normal, male-sterile, and restored versions of Zea mays L. Differences in leaf thickness were obtained between lines, but not between versions (except for one line). Differences in trichomes between versions were found in two of the five lines. Results from the length and width of stomatal and epidermal cells in the hybrid F44 × F6 were like those of the trichomes. Therefore, the large morphological variations between the internodes of normal, male-sterile, and restored versions of corn which were previously observed do not extend to the leaves.
CELL SIZE, NUCLEAR SIZE AND DNA CONTENT RELATIONSHIPS IN GOSSYPIUM
Authors: Edwards G. A. , Endrizzi J. E.
Published: November 2014

Cell and nuclear volumes were determined for 17 species and plant types in the genus Gossypium. All species and types, except one, showed a significant positive association between nuclear and cell volume. The overall species r-value (0.694) for cell and nuclear volume is highly significant and positive. For the 17 plant forms, the r-values for association of DNA content and nuclear volume and for association of DNA content and cell volume are 0.625 and 0.655, respectively, and both are highly significant.
IDENTIFICATION OF THE SEX CHROMOSOMES IN THE BALD EAGLE
Authors: Au W. , Fechheimer N. S. , Soukup S.
Published: November 2014

Karyotypes of five American bald eagles (Haliaeetus leucocephalus and H. alacanus) are compared. All had 2n = 66 chromosomes which fell into 3 size groups: A, 20 pairs of biarmed chromosomes; B, 9 pairs of acrocentric chromosomes and C, 4 pairs of microchromosomes. C-banding was done in two eagles and a heterochromatic W chromosome was identified in a presumptive female. The ZZ and ZW chromosomes could be identified in the karyotypes.
CENTROMERIC REGION PAIRING IN SOMATIC CHROMOSOMES OF THE MIDGE CHIRONOMUS TENTANS (DIPTERA: CHIRONOMIDAE)
Authors: Crozier R. H.
Published: November 2014

Supraoesophageal ganglion metaphases of Chironomus tentans larvae exhibit seven apparent metacentric chromosomes instead of the six metacentrics and two acrocentrics expected (n = 4). This is explicable by the fourth chromosome pair pairing in the centromere region. There is also a small percentage of cells with an apparent haploid set of larger chromosomes. The evidence suggests that these cells are diploid with the chromosomes paired at the centromere region.
CYTOGENETICS OF SOME SPECIES AND NATURAL HYBRIDS IN PROSOPIS (LEGUMINOSAE)
Authors: Hunziker J. H. , Poggio L. , Naranjo C. A. , Palacios R. A. , Andrada A. B.
Published: November 2014

Cytological results on 12 species and 4 putative hybrids of Prosopis are presented. Of these, 5 species and 4 hybrids have been hitherto unknown cytologically. The following species proved to be diploid (2n = 28) and constitute new chromosome number determinations for the genus: P. algarobilla Griseb., P. hassleri Harms, P. nigra (Griseb.) Hieron., P. patagonica Speg., P. tamarugo Phil. The diploid nature of some races of P. juliflora (Sw.) DC. is established; apparently under this taxon there are also tetraploid populations. The following putative interspecific hybrids showed regular meiosis with formation of 14 bivalents: P. vinalillo Stuck. (P. ruscifolia × P. alba?), P. alba × P. nigra? and P. hassleri × P. ruscifolia?.So far 28 taxa of the genus have been studied cytologically; 27 of these are diploid. The scarcity of polyploidy in the genus (3.5%) might be a consequence of the almost general lack of means of vegetative reproduction and of the absence of chromosome repatterning in primary speciation. Results of other authors concerning cytological data are also discussed.
TRISOMY IN AEDES AEGYPTI
Authors: Brat S. Ved , Rai K. S.
Published: November 2014

A trisomic (2n = 6 + 1) pupa of the yellow fever mosquito Aedes aegypti has been found. The trisomy involved chromosome 3 which is intermediate in size between 1 and 2. The extra chromosome formed a univalent or a trivalent during meiosis.
LINKAGE OF A GENE FOR DDT–RESISTANCE IN ADULTS OF THE MOSQUITO AEDES AEGYPTI
Authors: Hitchen Judith M. , Wood R. J.
Published: November 2014

The gene RDDT2, which gives resistance to DDT in the imago of Aedes aegypti L. has been mapped on linkage group III with respect to six visible markers. The best interpretation of the order of the genes is:–blp – blt – co – fz – wi – RDDT2 – min, but the orderblp – blt – co – fz – RDDT2 – wi – min is also possible.
CARYOTYPES, CHROMOSOMES SURNUMERAIRES, PARTHENOGENESE RUDIMENTAIRE ET POLYPLOIDIE CHEZ DEUX ESPECES DU GENRE PHRONIMA (CRUSTACES, AMPHIPODES)
Authors: Laval Ph. , Lecher P.
Published: November 2014

The diploid number of Phronima sedentaria and P. atlantica is 30, all the chromosomes are metacentric or submetacentric; the caryotypes of these two species are compared with those of other Amphipods. Some individuals of each species have a supernumerary chromosome. This element, found in both sexes, remains as an univalent at meiosis and goes earlier to one pole. In some cases nonfertilized ova undergo segmentation; this rudimentary parthenogenesis stops quickly and is partly related to polyploidization.
HOMOEOTIC EFFECT OF THE TUMOROUS-HEAD MUTANT AND DIFFERENTIAL EFFECT OF AN ENHANCER GENE IN THE TUMOROUS-HEAD STRAIN OFDROSOPHILA MELANOGASTER
Authors: Kuhn David T. , Dorgan Suzanne F.
Published: November 2014

Homoeotic effects (one organ replaced by an organ from a different part of the body) were investigated in the tumorous-head phenotype in Drosophila melanogaster. The tumorous-head mutant is the only known maternally effected homoeotic mutant (Postlethwait and Schneiderman, 1973). As reported by Postlethwait et al. (1972) transformations from eye to abdominal like structures, eye to antennal like structures, eye to palpus like structures, rostralhaut to genital like structures, rostralhaut to clasper teeth, and rostralhaut to antennal like structures were observed. Transformations currently observed but not by Postlethwait et al. (1972) are: eye to genital structures (resembling anal plates in both sexes or lateral plates in males); antenna to genital like structures; rostralhaut to abdominal like structures; and proboscis to leg like structures. Since a tumorous-head strain selected for high penetrance and expressivity was used for this study, differences between the two studies are ascribed to strain selection. Effect of a third chromosome gene which acts to enhance the tumorous-head maternal effect was also investigated. A highly significant increase in expressivity was found especially in females. Of 4,730 female flies examined possessing the enhancer gene, high penetrance and high expressivity, only the eye-antennal imaginal disc and possibly the libial disc showed destabilization. We observed no destabilization of the wing disc by the tumorous-head genes as predicted by Kauffman (1973).
ASSOCIATION OF PINK ALBINO SEEDLINGS WITH A RADIATION-INDUCED TRANSLOCATION OF CUCUMBER
Authors: Whelan Ernest D. P.
Published: November 2014

Pink seed, which germinated faster than normal seed and gave albino seedlings with a pinkish color, segregated from all selfed fruit from plants of cucumber (Cucumis sativus L.) heterozygous for a radiation-induced translocation. The segregation ratio in some populations suggested monogenic, recessive inheritance. No pink seed or pink albino mutants segregated from fully fertile progeny of translocation heterozygotes and no homozygous translocation lines were found. It is suggested that the lethal albino mutation is associated with the induced interchange.
DRUG RESISTANCE AND MEMBRANE ALTERATION IN MUTANTS OF MAMMALIAN CELLS
Authors: Ling Victor
Published: November 2014

Independent colchicine-resistant (CHR) mutants of Chinese hamster ovary cells displaying reduced permeability to colchicine have been isolated. A distinguishing feature of these membrane-altered mutants is their pleiotropic cross-resistance to a variety of unrelated compounds. Genetic characterization of the CHRlines indicates that colchicine resistance and cross-resistance to other drugs are of a dominant nature in somatic cell hybrids. Revertants of CHRhave been isolated which display decreased resistance to colchicine and a corresponding decrease in resistance to other drugs. These results strongly suggest that colchicine resistance and the pleiotropic cross-resistance are the result of the same mutation(s). Biochemical studies indicate that although colchicine is transported into our cells by passive diffusion, no major alterations in the membrane lipids could be detected in mutant cells. However, there appears to be an energy-dependent process in these cells which actively maintains a permeability barrier against colchicine and other drugs. The CHRcells might be altered in this process. A new glycoprotein has been identified in mutant cell membranes which is not present in parental cells, and is greatly reduced in revertant cells. A model for colchicine-resistance is proposed which suggests that certain membrane proteins such as the new glycoprotein of CHRcells, are modulators of membrane fluidity (mmf proteins) whose molecular conformation regulates membrane permeability to a variety of compounds and that the CHRmutants are altered in their mmf proteins. The possible importance of the CHRcells as models for investigating aspects of chemotherapy related to drug resistance is discussed.
INNOVATIVE APPROACHES TO GENETICS IN AGRICULTURE
Authors: Holl F. B.
Published: November 2014

The problems of feeding a rapidly expanding world population with decreasing arable land resources are placing increasing demands on our genetic resources and the plant breeders who exploit them. Innovative or novel genetic approaches may provide solutions to some of the problems of genetic analysis and the development of additional genetic variability in plants. The present status of techniques such as wide crossing, DNA feeding, tissue, cell and protoplast culture and somatic cell hybridisation is discussed. Plant tissue culture procedures may enable us to expand the gene pools for disease and pest resistance, greater tolerance to environmental stress, increased quality or possibly to develop new plant types. However, the utility of innovative procedures will require a rigorous evaluation of their potential and limitations, and the ability to produce material which can be readily introgressed into established plant breeding systems.
GENETIC STUDIES ON WALKING BEHAVIOR IN DROSOPHILA MELANOGASTER I. SELECTION AND HYBRIDIZATION ANALYSIS
Authors: Choo Jong-Kil
Published: November 2014

Rapid vs. slow types of walking behavior in Drosophila melanogaster were tested in response to light in a connected test-tube apparatus. The effect of selection for both types of behavior was clearly recognized after only a few generations. The heritability of the two traits of walking behavior was remarkably different; the former was estimated to be about 7%, the latter 26%. Walking behavior is possibly controlled by a major gene with the behaviour manifesting slow response to light being dominant to that manifesting rapid walking behavior.
EXTRA-LARGE TRIBOLIUM CONFUSUM: A NEW AUTOSOMAL RECESSIVE MUTANT
Authors: Vardell H. H. , Brower J. H.
Published: November 2014

A new mutant of Tribolium confusum Jacquelin duVal (Coleoptera: Tenebrionidae), extra-large (designated xl), was isolated in mating competition tests with red-eye (re) and wild-type (+). Crosses showed that it was autosomal recessive gene with subvital effects. The pupal weights averaged 6.1 and 7.3 mg for males and females, respectively, about twice the weights of the ancestral wild-type. The generation time (egg to adult) was approximately 8 to 9 weeks compared with about 4 weeks for the wild-type. This increase resulted from a lengthening of the larval stage since the durations of the egg and pupal stages were within the ranges of the wild-type. Mean longevity of xl males and females was reduced to 8.5 and 6.0 weeks, respectively at 26.7 ± 1 °C and 60% RH.
IN VITRO PRODUCTION OF PLANTS FROM POLLEN IN BRASSICA CAMPESTRIS
Authors: Keller W. A. , Rajhathy T. , Lacapra J.
Published: November 2014

Embryogenesis was induced in anthers of two cultivars of B. campestris L. cultured on a modified B5 medium of Gamborg and co-workers (1968). Analysis of mature plants derived from the embryoids revealed the presence of diploids and polyploids. It was, however, demonstrated that the plants were derived from pollen.
IDENTIFICATION OF THE MOUSE CHROMOSOMES BY MICRODENSITOMETRY
Authors: Léonard A. , Decat G.
Published: November 2014

Densitometric analysis has been performed on mouse chromosomes from "in vivo" preparations stained with Giemsa after trypsinisation. The characteristic curves obtained by analysing the same chromosome after different durations of trypsinisation suggest that a trypsinisation step is not always necessary to get an analysable banding pattern. The best results are obtained when the chromatids are long and closely appressed and by analysing the positive photomicrographs.
ADDITIONAL OBSERVATIONS ON THE PREPARATION OF R BANDED HUMAN CHROMOSOMES WITH ACRIDINE ORANGE
Authors: Verma Ram S. , Lubs Herbert A.
Published: November 2014

A number of technical factors which affect acridine orange R banding (RFA banding) were studied. These variables included age of slide, timing of fixation, details of incubation, mounting and the use of sequential technics. Optimal RFA banding was obtained between 15 and 20 days but good or very good preparations were obtained between 7 days and 2 months. Improved results were obtained in slides that were 3–4 months old by refixing the slides in ethanol acetic acid. Intermittent movement of slides during incubation in buffer as well as the details of mounting and removal of cover slips were found to be important. The best sequential banding was obtained with the sequence of Q to R but good results were obtained with the sequence G to R using ASG banding. Satisfactory results with the sequence R to C were not obtained. With careful attention to these variables good RFA banding can be obtained over a period of several months.
WHOLE MOUNT ELECTRON MICROSCOPY OF POLYTENE CHROMOSOMES FROM DROSOPHILA MELANOGASTER
Authors: Burkholder Gary D.
Published: November 2014

A simple method of whole mount electron microscopy has been developed to study the fine structural organization of Drosophila melanogaster polytene chromosomes. This method preserves the structural features of these chromosomes and may be of use for rapid gene localization at the ultrastructural level. Chromosome bands were electron dense regions composed of closely packed groups of chromomeres; thin bands consisted of a single row of transverse chromomeres, while thicker bands were composed of two to several rows of chromomeres. Interband regions contained relatively straight chromatin fibres which traversed the interband zone either singly or in bundles of several fibres. The interband chromatin fibres were generally 130 Å in diameter or thicker, and appeared to be composed of two or more thinner (80-90Å) fibres. Presumptive puff regions were characterized by extended chromatin fibres having a longitudinal orientation, however some transverse rows of chromomeres were also seen in these regions, suggesting that not all of the chromomeres in a band may be involved in puff formation. The chromatin fibres in the puffs were frequently thinner than those found in the interband regions. In stretched chromosomes, the chromatin fibres were drawn out into a mass of parallel fibres without any distinction between band and interband regions, supporting the hypothesis that individual chromatids are continuous through both band and interband regions and probably extend throughout the whole chromosome. No core fibres were observed in any of the polytene chromosomes studied.
STUDIES OF THE HERBICIDE PARAQUAT: I. Effects on the cell cycle and DNA synthesis in Vicia faba
Authors: Bell Sandra L. , Schwarz O. J. , Hughes Karen W.
Published: November 2014

Vicia faba root tips were exposed to concentrations of paraquat ranging from 10−3M to 10−6M. There was a statistically significant inhibition in 3H-thymidine incorporation, and, therefore, presumably of DNA synthesis by all concentrations of paraquat studied. All concentrations of paraquat also had a statistically significant effect on the percentage of cells in division at various hours following paraquat treatment. At 10−3M and 10−4M paraquat there was an almost total inhibition in the number of cells moving from the S period and through the G2 period and into division. Cells treated with 10−6M paraquat, however, did move through the G2 period and into division. A concentration of 10−4M paraquat did not result in an increase in chromosome aberrations.
SEX CHROMATIN AND CHROMOSOME NUMBERS IN LEPIDOPTERA
Authors: Ennis T. J.
Published: November 2014

Three classes of sex chromatin (SC) distribution have been encountered in a sample of Canadian Lepidoptera. In 78 of the 103 species examined, females were SC positive and males were SC negative. In another 24 species, females and males were SG negative. Females and males of a single species, Eucordylea resinosae, had two equal-sized SC bodies in interphase nuclei. In no species were females found to be SC negative and males SC positive. Usually, presence of SC indicates an XX♀: XY♂ sex-determining mechanism, and its absence, XX♀: XO♂, but the exceptional occurrence of SC in females and males of a species suggests the need for caution in too universal an application of this interpretation. Chromosome numbers have also been determined for 53 of the 103 species. Male haploid numbers ranged from 11 to 61, but 30 was most frequently encountered.
THE SYNTHESIS OF COMPOUND AUTOSOMES IN THE AUSTRALIAN SHEEP BLOWFLYLUCILIA CUPRINA
Authors: Foster G. G. , Whitten M. J. , Konowalow C.
Published: November 2014

The synthesis of the first compound chromosome strain in Lucilia cuprina (Diptera: Calliphoridae) (Weidemann) is described. Crosses between the compound chromosome strain and a chromosomally normal strain produce no offspring, whereas crosses between compound chromosome-bearing individuals are fertile. Cytological evidence is presented that compound chromosome arms assort at random with respect to one another during spermatogenesis.
GENETICS OF TWO BLOOMLESS MUTANTS IN BRASSICA CAMPESTRIS
Authors: Stringam Gary R.
Published: November 2014

The inheritance of two bloomless mutants was studied in Brassica campestris L. Both mutants were monogenically controlled recessives. Their use in insect susceptibility, disease resistance, and genetic studies is discussed.
CHROMOSOMAL ABERRATIONS IN A DIPLOID HAWORTHIA SUBFASIATA
Authors: Chinnappa C. C. , Semple J. C.
Published: November 2014

In two diploid specimens of Haworthia subfasciata (2n = 14) several kinds of chromatid and subchromatid aberrations occurred. In some pollen mother cells E-type and U-type bridges were present. In other cells bridges and fragments were formed due to asymmetrical reunion of nonsister chromatids following breakage. A translocation involving the satellites of two L pair chromosomes was observed in one plant.
CYTOGENETIC ANALYSIS OF HOMOZYGOUS SEGREGATION DISTORTER MALES OFDROSOPHILA MELANOGASTER
Authors: Erickson John , Hartl Daniel L.
Published: November 2014

Certain homozygous SD males are nearly sterile. Sterility is not due to aneuploid gametes — no significant second chromosome nondisjunction was found in matings to attached-2 and mei-S332 females. Some fourth chromosome aneuploidy was observed here, and in the cytological work. Otherwise, cytology of the meiotic divisions was essentially normal. Early spermatid bundles are normal, sperm head counts approximating the normal 64. In the later, coiled bundle stage, one observes less than 30 heads, many of which are grossly abnormal: twisted, club-like, or globular. In double mating experiments, SD/SD sperm did not displace normal sperm introduced first. In the reverse experiment, sperm (or fluid) from SD/SD males markedly reduced capacity of the females to store and utilize sperm from normal males, as scored from progeny and by counts of stored sperm. No sperm were seen in the storage organs of females imseminated first by SD/SD males, then by normal males. Many females refuse such a second mating. Our observations are quantitatively different from those with heterozygous SD males, but qualitatively similar, supporting the view that the near sterility of homozygous SD males arises from a mechanism of sperm dysfunction like that in SD/+ males.
IDENTIFICATION OF CHROMOSOMES IN SECALE MONTANUM AND INDIVIDUAL S. MONTANUM CHROMOSOME ADDITIONS TO 'KHARKOV' WHEAT BY HETEROCHROMATIN BANDS AND CHROMOSOME MORPHOLOGY
Authors: Gustafson J. P. , Evans L. E. , Josifek K.
Published: November 2014

Heterochromatin staining along with chromosome morphology was used to identify the chromosomes of Secale montanum Guss. in five accessions. The characteristics of all seven S. montanum chromosomes were fairly consistent from accession to accession. The S. montanum chromosomes were easily identified, and could be distinguished from the seven S. cereale L. chromosomes. Four disomic addition lines of S. montanum accession 2D23 to 'Kharkov M.C. 22' wheat were also analysed and identified.
THE FUNCTION OF MITOCHONDRIAL GENES INNEUROSPORA CRASSA
Authors: Bertrand H. , Szakacs N. A. , Nargang F. E. , Zagozeski C. A. , Collins R. A. , Harrigan J. C.
Published: November 2014

The 18 extranuclear mutants of Neurospora crassa, without exception, have abnormal mitochondrial respiratory systems. On the basis of genetic, phenotypic and physiological criteria, these mutants are divided into four groups: 1) the cytochrome aa3and b deficient "poky" variants that are defective in mitochondrial ribosome assembly, 2) the cytochrome aa3deficient mutants, [mi-3] and [exn-5], that appear to have genetic lesions affecting a component of a regulatory system controlling cytochrome aa3synthesis, 3) the cytochrome aa3and b deficient "stopper" mutants with physiological lesions that probably affect mitochondrial protein synthesis, and 4) cni-3, a mutant that is constitutive for an inducible mitochondrial cyanide-insensitive oxidase in spite of having a normal cytochrome mediated electron-transport system. It is proposed that the mitochondrial genophore not only codes for cellular components that are essential for the formation of the mitochondrial protein synthesizing apparatus, but also for components of a regulatory system that coordinates the expression of nuclear and mitochondrial genes during the biogenesis of the mitochondrial electron-transport system.
GENETIC VARIANCES IN AN EIGHT PARENT HALF DIALLEL OF OATS
Authors: Sampson D. R. , Tarumoto I.
Published: November 2014

Twenty-eight progenies with their eight parent cultivars of Avena saliva L. (2n = 6x = 42) were grown in F1, F2 and F3 in separate years; the F1 as spaced plants, the F2 and F3 as dense seeded populations. Additive genetic variance constituted most of the phenotypic variance of eight traits (heading date, plant height, stem diameter, grain yield and four components of yield) according to a Griffing Method 4, Model II analysis. Similarly, additive × year interactions were more important than nonadditive × year interactions. A Hayman-Jinks analysis of the same material but with the parents included showed that the additive component was 2 to 16 times larger than the dominance components in the F1 However in the F2 and F3 the dominance components became larger than the additive components for most traits instead of declining in importance as expected. Further, tests of fit to the hypotheses underlying the Hayman-Jinks analysis were negative in 8 of 24 cases. It is postulated that these discrepancies result from epistatic variance which caused an upward bias in the dominance estimates. The calculation and uses of two estimates of narrow-sense heritability are discussed.
L'ORGANISATION MITOCYCLIQUE DU MERISTEME RADICULAIRE ETUDIEE SUR LACTUCA SATIVA
Authors: Essad Sadi
Published: November 2014

The analysis of root meristems Lactuca sativa L. by the pulse labelled mitoses (PLM) and cytophotometric methods provides evidence for a model of root meristem mitocyclic organization. Three main points may be emphasized: 1) only one mitocyclic population is present. 2) two different mitocyclic cell flows occur: the more important in G1-S (about 5% per h) and the second in G2-M (about 4% per h). This situation results from the feeding of the G0 population: the 42% G02C and 8% G04C fractions are respectively fed from the post-mitotic and post-DNA synthetic cell flows. Thus the G0 population allows for the stability of the mitocyclic cell population. This system can be termed pseudoexponential. 3) a restricted but regular cell flow occurs from the G0 to the mitocyclic population.
GRAPHICAL ANALYSIS OF TILLER AND EAR PRODUCTION IN A DIALLEL CROSS OF BARLEY
Authors: Jana S.
Published: November 2014

The analysis of array variance and covariance for number of tillers and ears produced per plant was carried out in an 8 × 8 complete diallel cross of barley (Hordeum vulgare L.). Non allelic interactions ascribable to four near isogenic derivatives of a California cultivar distorted the variance-covariance relationship for both characters in two seasons. Removal of the epistatic parents resulted in satisfactory Wr/Vr graphs. A similar manipulation of grain yield data in an earlier study did not produce satisfactory results. The relatively simple inheritance of tiller and ear productivity may have resulted in the successful application of the diallel technique.
C-BANDING OF RYE CHROMOSOMES WITH COLD SSC BUFFER
Authors: Limin A. E. , Dvořák J.
Published: November 2014

Various times, temperatures and concentrations of SSC were tested in an attempt to elucidate the mechanism of C-banding in plants. It is shown that C-bands can be induced in rye (Secale cereale L.) chromosomes by SSC treatment at temperatures as low as 0 °C for periods as short as 1 min, an effect previously unknown in either plants or animals. Barium hydroxide treatment appears to be essential for the production of bands. If chromosomes are treated with SSC omitting the Ba(OH)2 treatment, relatively uniform loss of nucleoproteins occurs without the production of C-bands. It is suggested that Ba(OH)2 alters the chemical structure of nucleoproteins in heterochromatin rendering them insoluble in SSC. It is unlikely that SSC functions as a DNA reassociation agent in the production of C-bands. More likely it functions as a leaching agent which extracts soluble nucleoproteins from the chromosomes. Incubation in 2 × SSC at room temperatures for 5-10 min was found to be sufficient for the production of a well contrasted banding pattern in rye chromosomes.
DOMINANT-AND-RECESSIVE EPISTASIS IN A HOMEOTIC MOSQUITO MUTANT
Authors: Bhalla Satish C.
Published: November 2014

Folowing selection for 15 generations a pure strain of a homeotic mutant spur was isolated from a Brazilian population of the mosquito Culex pipiens fatigans. Monohybrid crosses showed a 13:3 segregation indicating dominant-and-recessive epistasis for wild-type vs. spur. This implies that a dominant allele at one locus and a recessive at the other interact to produce the mutant phenotype. Dihybrid crosses with linkage group II markers yellow and ruby gave 39:13:9:3 ratios indicating independent segregation. However, the dihybrid cross with linkage group I marker maroon showed a highly significant departure from 39:13:9:3 ratio. Data available indicate that the phenotype spur is controlled by a dominant epistat in linkage group III and a recessive epistat (approximately 31.9 crossover units from maroon) in linkage group I.
THE KARYOTYPE OF ASTER ERICOIDES (ASTERACEAE): SOME CANADIAN POPULATIONS
Authors: Semple John C.
Published: November 2014

Chromosome number determinations from five populations of Aster ericoides L. were either n = 5 or 2n = 10. Measurements of short and long arms of each pair of chromosomes are given. Previous reports of the chromosome number of the species are discussed. Some aneuploidy may be occurring in the species.
THE GENOMIC ORIGIN OF THE UNPAIRED CHROMOSOMES IN TRITICALE
Authors: Thomas J. B. , Kaltsikes P. J.
Published: November 2014

Differential staining of telomeric rye heterochromatin and telocentric chromosomes were used to identify chromosomes which were unpaired at first meiotic metaphase of hexaploid triticale (× Triticosecale Wittmack). Both approaches showed that it was the rye chromosomes which were seen as univalents. Differences in the rate of pairing from triticale to triticale were mostly explained by variation in the pairing of the rye genome. Within the rye genome, chromosome arms with telomeric heterochromatin showed pairing rates much lower than chromosome arms lacking heterochromatin. Wheat telocentrics and heterochromatin-free rye telocentrics which showed intermediate levels of pairing failure (65-90%), had mostly terminal chiasmata. On the other hand rye telocentrics with large heterochromatin bands on the telomeres had mostly nonterminal chiasmata and very low pairing (5-35%). It is concluded that the presence of heterochromatin on certain telomeres of rye chromosomes blocks the formation of terminal chiasmata and this results in desynapsis and univalents at MI.
COLCHICINE INDUCED BIVALENT PAIRING OF TETRAPLOID MICROSPOROCYTES INTRITICUM LONGISSIMUMANDT.SPELTOIDES
Authors: Avivi Lydia
Published: November 2014

The low-pairing gene or genes of diploid Triticum longissimum (Schwinf. &Muschl.) Bowden predispose the induced autotetraploid towards bivalent pairing. In this work, bivalentization was phenocopied in intermediate- and low-pairing lines of T. longissimum and in a high-pairing line of T. speltoides (Tausch) Gren. ex Richter, by colchicine treatment during the last premeiotic mitosis. This treatment induced C-mitosis and tetraploid cells which are characterized by almost exclusive bivalent pairing instead of the expected multivalent pairing. Colchicine disrupted the association of homologous chromosomes in the premeiotic metaphase but left the sister chromatids located close to each other. As a result, rather than being all closely associated, the four homologues were arranged in pairs already prior to meiosis. The effect of colchicine in this respect is reminiscent of that of the "diploidizing genes" in many naturally occurring polyploids. This work demonstrates once again the significance which the pattern of premeiotic homologous association has for the manner of meiotic pairing.
MEIOTIC EVIDENCE FOR PERICENTRIC INVERSION POLYMORPHISM INJUNCO(AVES)
Authors: Shields Gerald F.
Published: November 2014

Species of the genus Junto are polymorphic for chromosomes 2 and 5. Diplotene karyotypes of 61 adult male Dark-eyed Juncos, Junco hyemalis, were analyzed in order to determine the basis of the polymorphisms. Individuals carrying heterozygous bivalents of the polymorphic chromosomes have fewer chiasma than homozygous individuals. These data suggest that two separate pericentric inversions are at the basis of the polymorphisms.
EVOLUTION OF AVENA SATIVA: ORIGIN OF THE CYTOPLASMIC GENOME
Authors: Steer Martin W. , Thomas Hugh
Published: November 2014

Comparisons of the isoelectric points of the large subunits from the enzyme ribulose biphosphate carboxylase, extracted from species and hybrids of Avena, provide conclusive evidence for the origin of the cytoplasmic genome of the hexapioid A. sativa L. from the A. genome diploids rather than the C genome diploids.
HAPLOIDS FROM BARLEY × RYE CROSSES
Authors: Fedak George
Published: November 2014

Haploids of barley (Hordeum vulgare L. emend. Lam.) were recovered at a frequency of less than 1% from pollinations of five strains of barley with the diploid rye cv. Prolific. This is the first report of barley haploids obtained from barley × rye crosses. Preliminary studies suggest that haploids arose through a process of elimination of rye chromatin. At metaphase I in the haploids a small degree of nonhomologous pairing expressed as bivalents and trivalents or secondary associations was observed.
VIABILITY ESTIMATES FOR SIXTY TOMATO MUTANTS
Authors: Butler L.
Published: November 2014

Monogenic segregation data for 60 mutants show that for 42 of them the observed number was less than the expected and 25 of these 42 were significantly less. In many cases the discrepancy was too small to de detected in populations; of less than 500 plants. In no case was the mutant more viable than the wild type allele unless one accepts data for mutants H and o which appear to be cases of misclassification. The cause of the inviability was obvious in many cases where the mutant was slow growing (I, dil, tf), or poor germinating (ro, au, dpy), but in many cases the mutant wais as vigorous as the wild type. There were two types of change in viability, in the first case newly arisen mutants became more viable as the result of selection on different genetic backgrounds, in the second case there was a sudden change in viability because the mutant became associated in coupling phase with a lethal gene. The segregation ratios of genes at the proximal end of chromosome 2 are affected by the gametic eliminator (gt) whereas segregations in the central region, in the vicinity of aw, are affected by a chromosomal rearrangement. Genes at the distal end of chromosome 2 may have distorted ratios because of a lethal near the bip locus. The importance of uniform background and planned experiments is pointed out.
THE TRANSFER TO WHEAT AND HOMOEOLOGY OF AN AGROPYRON ELONGATUM CHROMOSOME CARRYING RESISTANCE TO STEM RUST
Authors: Knott D. R. , Dvořák J. , Nanda J. S.
Published: November 2014

A stem rust resistant wheat-Agropyron derivative obtained from Dr. F. X. Laubscher was crossed and backcrossed to Triticum aestivum L. cv. Marquis to determine the inheritance of its resistance to stem rust. Resistance proved to be carried on an Agropyron chromosome. A substitution line was obtained in which the Agropyron chromosome had replaced wheat chromosome 7D. The Agropyron chromosome compensates well for 7D in both plants and gametes and must, therefore, be homoeologous with the chromosomes of group 7. It is homologous with chromosome 7el1, the Agropyron chromosome carrying leaf rust resistance in Agrus, and it is, therefore, designated 7el2. Like 7el1 it carries a gene that results in a high level of yellow pigment in the flour. The frequent occurrence of genes for rust resistance on Agropyron chromosomes of homoeologous group 7 suggests that they may be related by descent.
NUCLEAR SUPPRESSORS OF THE [POKY] CYTOPLASMIC MUTANT INNEUROSPORA CRASSA: II. Mitochondrial Cytochrome Systems
Authors: Bertrand H. , Kohout J.
Published: November 2014

The mitochondrial cytochrome aa3and b deficiencies of the [poky] cytoplasmic mutant of Neurospora crassa are partially suppressed by mutant alleles of any one of six nuclear genes, namely sup-1, sup-3, sup-4, sup-5, sup-10 and sup-14. The suppressor-induced increases in the concentration of both cytochromes are detected in the mitochondria from exponentially growing [poky] cultures, and, thus, are clearly distinguishable from the age-dependent changes in the cytochrome system that occur in cultures that approach, or have reached, the stationary phase of growth. The relative amounts of mitochondrial cytochromes aa3and b show a direct correlation with the relative efficiency of the various sup genes as suppressors of the slow-growth phenotype of [poky]. Since [poky] is defective in mitochondrial protein synthesis due to a lack of 30 S mitochondrial ribosomal subunits, it is proposed that the six suppressors promote the assembly of functional mitochondrial ribosomes.
CHROMOSOME MORPHOLOGY DURING MEIOSIS OF NORMAL AND ROBERTSONIAN TRANSLOCATION-CARRYING RAMS (OVIS ARIES)
Authors: Chapman H. M. , Bruère A. N.
Published: November 2014

A detailed description is given of the meiotic chromosomes of the normal ram (54,XY) and of the chromosomes at diakinesis-metaphase I in rams heterozygous for the t1, t2 and t3 and homozygous for the t2 and t3 Robertsonian translocation chromosomes. Analyses were made on diakinesis-metaphase I chromosomes in 309 cells from normal rams and 2402 cells from the Robertsonian translocation carriers. Hypomodal cell counts were due to missing chromosomal elements and hypermodal counts were due either to separation of the chromosomes of the sex bivalent or to separation of the components of an autosomal bivalent. Trivalent formation was characteristic for the heterozygous Robertsonian translocation carriers while the homozygous carriers had an additional large bivalent. An association between the sex bivalent and a small autosomal bivalent at diakinesis-metaphase I is reported.
CONTROLLING ELEMENT ALLELES IN THE ANALYSIS OF THE GENETIC CONTROL OF THE ANTHOCYANIN PATHWAY IN MAIZE
Authors: Reddy Arjula R. , Peterson Peter A.
Published: November 2014

Controlling elements in maize become implanted at diverse loci. These include loci involved with the expression of the anthocyanin pathway in the aleurone tissue. The controlling elements effects on these loci lead to an array of diverse heritable expressions, ranging from colorless to full colored types. Four controlling-element alleles, a-m(r), a2-m(r) (colorless), a-m-1 and a2-m-1 (colored), which respond to the regulatory element En, have been tested for the accumulation of pigments of the anthocyanin pathway to ascertain the role of standard recessive a and a2 genes in the pathway. Data from thin-layer chromatography and absorption spectra clearly show that the triploid aleurone tissue of a-m(r)/a-m(r)/a-m(r) accumulates quercetin and that a2-m(r)/a2-m(r)/a2-m(r) accumulates leucoanthocyanidin. No qualitative differences, in terms of anthocyanin pigments, were observed between a-m-1, a2-m-1 and their corresponding dominant alleles, A and A2. The dominant allele C-I completely inhibits the production of quercetin in a-m(r) tissue, leucoanthocyanidin in a2-m(r) and anthocyanin in a-m-1 and a2-m-1. The genetic control of the anthocyanin pathway in maize is discussed in view of these data.
GENETIC ANALYSIS OF EGG CANNIBALISM AND OVIPOSITION SITES FORTRIBOLIUM CASTANEUM
Authors: Englert DuWayne C. , Raibley Don W.
Published: November 2014

The roles of cannibalism site, oviposition site and adult distribution in producing differences in the egg cannibalism rates for adults of the wild-type and antennapedia strains of Tribolium castaneum were investigated. The effect of egg genotype (+ or ap) in contributing a preferential selection for eating was also examined. The ap adults cannibalized eggs at a lower rate than did + adults, particularly when presented + eggs; no preference was noted for the + strain. Geographic centers for cannibalism site, oviposition site and adult distribution did not differ significantly. However, uniformity of cannibalistic activity and adult distribution occurred only for the + adults, suggesting that the behavioral activities of the two strains contributed to the differences of egg cannibalism possibly through a difference in searching capabilities.