bluuebunny/crossref_metadata_2025_split huggingface dataset:
A MEIOTIC MUTANT DEFECTIVE IN DISTRIBUTIVE DISJUNCTION IN DROSOPHILA MELANOGASTER
Authors: Carpenter Adelaide T C 
Published: January 2021

ABSTRACT
The female meiotic mutant no distributive disjunction (symbol: nod) reduces the probability that a nonexchange chromosome will disjoin from either a nonexchange homolog or a nonhomolog; the mutant does not affect exchange or the disjunction of bivalents that have undergone exchange. Disjunction of nonexchange homologs was examined for all chromosome pairs; nonhomologous disjunction of the X chromosomes from the Y chromosome in XXY females, of compound chromosomes in females bearing attached-third chromosomes with and without a Y chromosome, and of the second chromosomes from the third chromosomes were also examined. The results suggest that the defect in nod is in the distributive pairing process. The frequencies and patterns of disjunction from a trivalent in nod females suggest that the distributive pairing process involves three separate events-pairing, orientation, and disjunction. The mutant nod appears to affect disjunction only.
RECOMBINATION IN DROSOPHILA MELANOGASTER MALE
Authors: Hiraizumi Yuichiro , Slatko Barton , Langley Charles , Nill Annegreth 
Published: January 2021

ABSTRACT
T-007 strain of Drosophila melanogaster is known to show recombination in males. The present study established the following points: (1) Clustering occurrence of recombinant, unequal recovery of complementary products of recombination, relatively high frequency of recombination around centromeric region, and relatively frequent occurrence of mosaic phenontype flies—all of these seem to indicate that a considerable fraction of male recombination in the T-007 strain is of premeiotic, or somatic origin, although a fraction still could be of meiotic origin; (2) Male recombination occurs in the third as well as in the second chromosomes, and the frequencies of recombinations are comparable between these two chromosome pairs.
REGULATION OF GENE FUNCTION: A COMPARISON OF X-LINKED ENZYME ACTIVITY LEVELS IN NORMAL AND INTERSEXUAL TRIPLOIDS OF DROSOPHILA MELANOGASTER
Authors: Lucchesi John C , Rawls John M 
Published: January 2021

ABSTRACT
We have measured gene function in normal and male-like intersexual triploids of Drosophila melanogaster by assaying crude extracts of whole flies or thoraces for levels of an X-linked (6-phosphogluconate dehydrogenase) and an autosomal (NADP-dependent isocitrate dehydrogenase) enzyme activity. Our observations lead us to conclude that each dose of the X-linked gene is more active in the cells of these intersexes than it is in normal triploid or diploid female cells. These results indicate that a level of activity intermediate between the normal male and female levels is possible for X-linked genes.
POPULATION GENETICS OF MARINE PELECYPODS. III. EPISTASIS BETWEEN FUNCTIONALLY RELATED ISOENZYMES OF MYTILUS EDULIS
Authors: Mitton Jeffry B , Koehn Richard K 
Published: January 2021

ABSTRACT
The distribution of interlocus genotypic combinations was examined in Mytilus edulis for interdependence between two loci synthesizing functionally related isoenzymes. There is significant dependence between the Leucine Aminopeptidase and Aminopeptidase loci, which we attribute to epistasis, since the magnitude of dependency varies with age. Furthermore, dependency varies in magnitude with position in the intertidal zone from which samples were taken, suggesting that epistasis is a function of the combination of certain non-homologous alleles as well as of the environmental circumstance in which the combinations occur.
EFFECTS OF POPULATION SIZE AND SELECTION INTENSITY ON SHORT-TERM RESPONSE TO SELECTION FOR POSTWEANING GAIN IN MICE
Authors: Hanrahan J P , Eisen E J , Legates J E 
Published: January 2021

ABSTRACT
The effects of population size and selection intensity on the mean response was examined after 14 generations of within full-sib family selection for postweaning gain in mice. Population sizes of 1, 2, 4, 8 and 16 pair matings were each evaluated at selection intensities of 100% (control), 50% and 25% in a replicated experiment. Selection response per generation increased as selection intensity increased. Selection response and realized heritability tended to increase with increasing population size. Replicate variability in realized heritability was large at population sizes of 1, 2 and 4 pairs. Genetic drift was implicated as the primary factor causing the reduced response and lowered repeatability at the smaller population sizes. Lines with intended effective population sizes of 62 yielded larger selection responses per unit selection differential than lines with effective population sizes of 30 or less.
BARLEY STRIPE MOSAIC VIRUS AND THE FREQUENCY OF TRIPLOIDS AND ANEUPLOIDS IN BARLEY
Authors: Sandfaer Jens 
Published: January 2021

ABSTRACT
BSMV infection caused a pronounced increase in the frequency of triploid and aneuploid seeds in eleven barley varieties, but with considerable variation in frequency among varieties. In some of the varieties triploids exceeded three per cent. In virus-free material a few triploids were found in most of the varieties, but the frequency was very low. There was, however, a significant variation among varieties.
COMPLEMENTATION ANALYSIS OF MALE FERTILITY AMONG THE SEGREGATION DISTORTER CHROMOSOMES OF DROSOPHILA MELANOGASTER
Authors: Hartl D L 
Published: January 2021

ABSTRACT
The fecundities of 55 genotypes of the form SDi/SDj, generated by 11 different SD chromosomes have been examined. Five of the genotypes are lethal The fecundities of the rest fall into a pattern of fertility and sterility that is highly suggestive of intracistranic complementation. The complementation leading to male fertility is only partial complementation: the fecundity of most fertile genotypes is less than half that of controls. The three components of the SD system, the Sd locus, the Ac locus, and the modifiers in 2R, were examined separately, and it appears that the complementation is a phenomenon associated with the Sd locus. A hypothesis of the molecular events involved in segregation distortion is formulated in the light of these observations. The model is based on the assumption that the Sd locus produces a multimeric molecule that regulates the activity of the Ac(=Rsp) locus during spermatogenesis.
CYTOGENETIC ANALYSIS OF PSEUDOLINKAGE OF LDH LOCI IN THE TELEOST GENUS SALVELINUS
Authors: Davisson Muriel Trask , Wright James E , Atherton Louisa M 
Published: January 2021

ABSTRACT
Cytological and genetic analyses provide evidence that spontaneous centric fusion and fission can account for curious patterns of pseudolinkage of two LDH loci in males of brook trout (Salvelinus fonthalis) and in the F1, F2, and backcross generations of lake trout (S. namaycush) × brosk trout hybrids. Intraindividual polymorphisms for acrocentric and metacentric chromosomes in somatic and gonadal tissue of these fish have been related to the proposed polyploid evolution in Salmonidae.
BIOMETRICAL GENETICS WITH ONE OR TWO LOCI: THE INHERITANCE OF PHYSIOLOGICAL CHARACTERS IN MICE
Authors: Stewart John , Elston R C 
Published: January 2021

ABSTRACT
Maximum likelihood methods have been used to compare the fit of twenty different genetic models to experimental data on fourteen characters, each measured on two parental strains, F1 hybrids and both backcrosses. Although variation in all characters was continuous, differentiation between the various models was meaningful, the mean likelihood ratio between the best and worst models for each character being greater than 1O4. Models with only one or two loci were adequate to account for the observed genetic variation in eleven of the fourteen characters. These results indicate that even in species without special genetic advantages, it may be possible to identify individually some of the genes responsible for naturally-occurring variation within the range of normality.
THE EFFECTS OF ENVIRONMENTAL HETEROGENEITY ON THE GENETICS OF FINITE POPULATIONS
Authors: Dickinson Heather , Antonovics Janis 
Published: January 2021

ABSTRACT
The effects on a panmictic population of a patchy environment and stochastic selection were investigated by computer simulation. The model allowed for different patterns and intensities of selection and various densities of distribution of the offspring. It delineated the effects of these variables on the correlation between the genotype and the environment, the level of heterozygosity, the change in gene frequency from generation to generation and the divergence between similar populations due to random effects.
A TEMPERATURE-SENSITIVE MUTANT IN TETRAHYMENA PYRIFORMIS, SYNGEN 1
Authors: McCoy J Wynne 
Published: January 2021

ABSTRACT
After treatment with nitrosoguanidine a mutation to temperature sensitivity was obtained in Tetrahymena pyriformis, syngen 1. The trait is controlled by a recessive allele, ts, at a locus linked to serotype locus T. IS is completely recessive, unlike any other allele studied in this organism, and the heterozygotes do not show vegetative assortment. The cross which revealed the linkage of ts and T failed to show evidence of the linkage of mt (mating type) and E-1 (esterase-I) which has been demonstrated in other crosses (ALLEN 1964; DOERDER 1972), but revealed a third case of linkage, involving mt and TO (tetrazolium oxidase). Taken together, these results are presumptive evidence for large interstrain differences in recombination properties within syngen 1.
GENETIC MAPPING IN SACCHAROMYCES IV. MAPPING OF TEMPERATURE-SENSITIVE GENES AND USE OF DISOMIC STRAINS IN LOCALIZING GENES
Authors: Mortimer R K , Hawthorne D C 
Published: January 2021

ABSTRACT
Through use of tetrad, random spore, trisomic, and mitotic analysis procedures a large number of genes, including 48 new genetic markers, were studied for their locations on the genetic maps of the yeast Saccharomyces cerevisiae. Eighteen new centromere linked genes were discovered and all but one was located on various ones of the 16 previously-established chromosomes. Five fragments of linked genes were also assigned to chromosomes; four were located on known chromosomes while the fifth determined one arm of a new chromosome. The experiments indicate that seventeen is likely to be the haploid chromosome number in this yeast. Most chromosomes have been established by genetic means to be metacentric and their genetic lengths vary from 5 cM to approximately 400 cM. Functionally-related sets of genes generally were found to be dispersed over the genome.
GENETIC CONTROL OF RECOMBINATION IN SCHIZOPHYLLUM COMMUNE: LOCATION OF A GENE CONTROLLING B-FACTOR RECOMBINATION
Authors: Koltin Y , Stamberg Judith 
Published: January 2021

ABSTRACT
In S. commune the frequency of recombination between the two subunits, α and β, of the B incompatibility factor is genetically controlled. Analysis of the progeny obtained from crosses between high- and low-recombining strains indicates that the gene controlling recombination frequency in the B factor is linked to the B factor itself, approximately nine map units from Bβ. This gene, called B-rec-1, does not affect the recombination frequency in an unlinked region (between the subunits of the A incompatibility factor) or in a region contiguous with the B factor (between Bα and the morphological marker dome-2).
DIRECTED EVOLUTION OF METABOLIC PATHWAYS IN MICROBIAL POPULATIONS II. A REPEATABLE ADAPTATION IN SACCHAROMYCES CEREVISIAE
Authors: Francis J C , Hansche P E 
Published: January 2021

ABSTRACT
A selection experiment was conducted for approximately 1,000 generations in a chemostat population of 109 cells of the haploid yeast, S. cerevisiae. The experiment was designed to enhance genetically the rate at which the external enzyme acid phosphatase catalyzed the hydrolysis of very low concentrations of β-glycerophosphate at an unfavorably high pH. The observed genetic adaptation in this experiment consisted of a mutation (ACP-2) in the acid phosphatase structural gene which effected a shift in the pH optimum of the enzyme and incremented its activity. The effects of ACP-2 and a similar mutation, ACP-1, on acid phosphatase substrate specificity are also reported.
LINKAGE RELATIONSHIPS OF SIX ENZYME LOCI IN INTERSPECIFIC SUNFISH HYBRIDS (GENUS LEPOMIS)
Authors: Wheat T E , Whitt G S , Childers W F 
Published: January 2021

ABSTRACT
Backcross hybrids produced from the bluegill, the red-ear sunfish, and their F1 interspecific hybrid have been analyzed for the inheritance of six enzyme phenotypes. Malate dehydrogenase A and B, tetrazolium oxidase, 6-phosphogluconate dehydrogenase, skeletal muscle esterase, and liver α-glycerophosphate dehydrogenase are all inherited in a mendelian manner as codominant alleles at nuclear loci. 6-phosphogluconate dehydrogenase and α-glycerophosphate dehydrogenase are encoded by linked loci, undergoing recombination at a frequency of 15%-22%. No other case of linkage was observed. The absence of linkage between the homologous malate dehydrogenase loci is of particular interest. These interspecific hybrids appear to be very useful for studies of biochemical genetics.
FERTILITY GENES IN NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER. I. FREQUENCY, ALLELISM AND PERSISTENCE OF STERILITY GENES
Authors: Oshima Chozo , Watanabe Takao K 
Published: January 2021

ABSTRACT
Three or four percent of the wild flies in natural populations of D. melanogaster have been found to be sterile. An analysis of sterility associated with the second chromosome revealed a much lower frequency of genetically sterile flies. The accumulation of sterility genes in a cage population was proportional to that of lethal genes, as were their equilibrium frequencies in several natural populations. Many sterile chromosomes were associated with low viability due to pleiotropic effects. The number of chromosomes leading to sterility in both sexes was larger than the expectation based on random combination of male and female sterility genes. This suggests that there is some linkage disequilibrium between male and female sterility genes, as well as a pleiotropic effect of single sterility genes. Some sterility genes were maintained in natural and cage populations, and the patterns of persistence of the sterility genes were very similar to those of lethal genes.
PROBABILITY OF FIXATION AND MEAN FIXATION TIME OF AN OVERDOMINANT MUTATION
Authors: Nei Masatoshi , Roychoudhury A K 
Published: January 2021

ABSTRACT
The probability of fixation of an overdominant mutation in a finite population depends on the equilibrium gene frequency in an infinite population (m) and the product (A) of population size and selection intensity. If m &lt; 0.5 (disadvantageous overdominant genes), the probability is generally much lower than that of neutral genes; but if m is close to 0.5 and A is relatively small, it becomes higher. If m &gt; 0.5 (advantageous overdominant genes), the probability is largely determined by the fitness of heterozygotes rather than that of mutant homozygotes. Thus, overdominance enhances the probability of fixation of advantageous mutations. The average number of generations until fixation of an overdominant mutation also depends on m and A. This average time is long when m is close to 0.5 but short when m is close to 0 or 1. This dependence on m and A is similar to that of Robertson's retardation factor.
DELETION MAPPING OF THE Λ REX GENE
Authors: Gussin Gary N , Peterson Victoria , Loeb Nancy 
Published: January 2021

ABSTRACT
Deletion mapping has been used to order 12 Λ rex- mutants. Correlation of recombination data with physically-determined positions of deletion end-points (SZYBALSKI 1971; BLATTNER et al. 1972) suggests that the left-most rex- mutation, rex209, is located about 260-300 nucleotide pairs from the PL mutation sex1 and abut 475 nucleotide pairs from the left end-paint of the region of nonhomology with Λimm434.
THE PRODUCT OF THE LEU-3 CISTRON AS A REGULATORY ELEMENT FOR THE PRODUCTION OF THE LEUCINE BIOSYNTHETIC ENZYMES OF NEUROSPORA
Authors: Polacco Joseph C , Gross S R 
Published: January 2021

ABSTRACT
A class of intracistronic (or closely linked) partial reversions of leu-3 mutations has been found to be conditionally constitutive with respect to the synthesis of isopropylmalate isomerase (specified by the leu-2 cistron) and β-isopropylmalate dehydrogenase (specified by the leu-1 cistron), two of the enzymes of leucine biosynthesis in Neurospora. The intermediate level of enzyme production by these leu-3cc mutants is independent of the obligatory inducer effector, α-isopropylmalate, but dependent upon the presence of the branched-chain amino acids, isoleucine, valine and leucine. The properties of leu-3+, leu-3 and leu-3cc in heterokaryons indicate that the transnuclear regulatory activity of the leu-3 product varies specifically as a function of available effector molecules. The information presented suggests that the leu-3 cistron is responsible not only for the production of a "positive" regulatory substance necessary for the expression of the leu-1 and leu-2 cistrons, but that it probably serves also a coordinating role in the expression of many of the genes involved in branched-chain amino acid metabolism.
TEMPERATURE-SENSITIVE MUTATIONS IN DROSOPHILA MELANOGASTER. XVII. HEAT- AND COLD-SENSITIVE LETHALS ON CHROMOSOME 3
Authors: Tasaka S Elaine , Suzuki David T 
Published: January 2021

ABSTRACT
Ethyl methanesulfonate-treated third chromosome of Drosophila melanogaster were tested for the presence of dominant and recessive temperature-sensitive lethal mutations at 17°, 22° and 29°C. Out of 1,176 chromosomes tested, no dominant ts lethals, 21 heat-sensitive, 22 cold-sensitive and 10 heat-cold-sensitive lethals were recovered. Heat-cold sensitivity was produced by a single mutation in all cases. Sixty-two percent of the ts lethals were fertile as homozygotes in both sexes. Surprisingly, 88% of the ts lethals mapped between st and Sb, a region straddling the centromere and estimated to comprise 12.9% of the genetic length and 55% of the physical length of chromosome 3. All but one of the heat- and cold-sensitive lethals complemented with each other at their respective restrictive temperatures.
GENE DOSAGE AND THE EXPRESSION OF ELECTROPHORETIC PATTERNS IN HETEROPLOID MOUSE CELL LINES
Authors: Farber Rosann A 
Published: January 2021

ABSTRACT
Spontaneously transformed mouse cell lines heterozygous for electrophoretic markers have been studied to determine the relationship between gene dosage and phenotype. It is shown that a clone with an electrophoretic pattern for glucosephosphate isomerase of three bands in a ratio of 4A:4AB:1B contains three copies of chromosome 7, which carries the gene for this enzyme. A clone from a different line with a pattern of three bands in a ratio of 1A:6AB:9B for NADP-isocitrate dehydrogenase has four copies of the chromosome carrying this gene or three copies plus a rearrangement which apparently involves this chromosome. These results show that all of the alleles for each enzyme are expressed to an equal extent in these cells.
DIFFERENTIAL RESPONSE TO SELECTION ON THE TWO SEXES IN DROSOPHILA MELANOGASTER
Authors: Palenzona Domenico Lorenzo , Alicchio Rita 
Published: January 2021

ABSTRACT
Artificial selection for short wing was performed in two Drosophila melanogaster populations with partially different gene pools: the C populations were derived from a Canton stock while the H lines were derived from a cross between Canton and a b, cn, vg strain. It is shown that in both populations selection on females (CF, HF) was more effective than selection on males (CM, HM). This difference cannot be explained in terms of differences in additive genetic variability between the two sexes because: (1) both sexes contribute to the genetic variability utilized by selection applied to one sex only, and (2) switching selection pressure on females in the M lines does not result in a response comparable to that obtained in the F populations; this rules out almost completely recombination as the responsible agent for the differences between the selection limits reached by M and F selections.—These results, together with several additional observations concerning sexual dimorphism, fitness and the effect of natural selection, suggest that a complex interaction should be involved in the differential response of M and F lines, controlling the wing length phenotype.
DNA FROM MAIZE WITH AND WITHOUT B CHROMOSOMES: A COMPARATIVE STUDY
Authors: Chilton Mary-Dell , McCarthy Brian J 
Published: January 2021

ABSTRACT
DNA preparations from 5B and 0B maize seedlings are indistinguishable in their buoyant density distribution in CsCl gradients. Their renaturation kinetics are identical at several stringency criteria. DNA competition studies fail to detect any component in 5B DNA redundant sequences which is lacking in 0B DNA. Homologous and heterologous duplexes formed between 5B and 0B DNA have virtually identical melting profiles. The DNA of B chromosomes is concluded to be very closely related to that of A chromosomes.
EVIDENCE FOR A SEX-LINKED HAPLO-INVIABLE LOCUS IN THE CUT-SINGED REGION OF DROSOPHILA MELANOGASTER
Authors: Lefevre G , Johnson T K 
Published: January 2021

ABSTRACT
Many cytologically normal and rearranged cut mutants have been reported, but no known deficiency involves both ct and its close neighbor, singed. This fact prompted an investigation of the mutational response of the ct-sn interval. Approximately 24,000 F1 female progeny of 7-day-old males given 2000 or 3000r X-ray exposures were examined for the presence of newly induced mutations at the Notch, carmine, ct, and sn loci. One sn, 2 cm-ct, 31 N, and 33 ct mutants were found, indicating that the frequency of recovery of ct mutants is much greater than that of either cm or sn, as high even as N. Among the F1 female progeny were two deficiency mutants that expressed both cm and ct (separated by 21 bands), but none expressed both ct and sn (separated by only 14 bands). Of the 18 cytologically analyzed ct mutants, two proved to be deficiencies; neither extended farther to the right than 7C1. No reported ct deficiency extends with certainty farther to the right than 7C4. This fact, together with the scarcity of sn deficiencies, suggests the presence of a haplo-insufficient locus between ct and sn that prevents recovery of ct-sn deficiencies. The analysis of the deficiency component of Tp snS93, a short transposition which moves most of the ct-sn interval from 7BC to 8D, proved the existence, just to the left of sn, of a haplo-inviable locus that prevents the development of females heterozygous for its deficiency.—A marked similarity between mutants at the N and ct loci was noted.
GENETIC RELATIONSHIP BETWEEN ARYL HYDROCARBON HYDROXYLASE INDUCIBILITY AND CHEMICAL CARCINOGEN INDUCED SKIN ULCERATION IN MICE
Authors: Thomas P E , Hutton J J , Taylor B A 
Published: January 2021

ABSTRACT
Inbred strains of mice show differential skin inflammatory reactivity following the topical application of polycyclic hydrocarbons. Strains also differ in the extent to which hepatic aryl hydrocarbon hydroxylase activity is induced by these compounds. Differential inflammatory response and hydroxylase inducibility are genetically controlled by alleles at the In and Ahh loci, respectively. Genetic analyses and strain surveys indicate that the In and Ahh loci are identical, or very closely linked.