bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic analysis of the Shaker gene complex of Drosophila melanogaster.
Authors: Ferrús A , Llamazares S , de la Pompa J L , Tanouye M A , Pongs O 
Published: April 2021

Abstract
The Shaker complex (ShC) spans over 350 kb in the 16F region of the X chromosome. It can be dissected by means of aneuploids into three main sections: the maternal effect (ME), the viable (V) and the haplolethal (HL) regions. The mutational analysis of ShC shows a high density of antimorphic mutations among 12 lethal complementation groups in addition to 14 viable alleles. The complex is the structural locus of a family of potassium channels as well as a number of functions relevant to the biology of the nervous system. The constituents of ShC seem to be linked by functional relationships in view of the similarity of the phenotypes, antimorphic nature of their mutations and the behavior in transheterozygotes. We discuss the relationship between the genetic organization of ShC and the functional coupling of potassium currents with the other functions encoded in the complex.
Molecular structure of frizzled, a Drosophila tissue polarity gene.
Authors: Adler P N , Vinson C , Park W J , Conover S , Klein L 
Published: April 2021

Abstract
The function of the frizzled (fz) locus is required to coordinate the cytoskeletons of pupal epidermal cells so that a parallel array of cuticular hairs and bristles is produced. We report here the molecular cloning and characterization of the fz locus. The locus is very large. Mutations that inactivate the gene are spread over 100 kb of genomic DNA. The major mRNA product of the gene is a 4-kb RNA that is encoded by 5 exons spread over more than 90 kb of genomic DNA. Conceptual translation of this mRNA indicates that it encodes an integral membrane protein that is likely to contain both extracellular and cytoplasmic domains.
Interval mapping of quantitative trait loci employing correlated trait complexes.
Authors: Korol A B , Ronin Y I , Kirzhner V M 
Published: April 2021

Abstract
An approach to increase the resolution power of interval mapping of quantitative trait (QT) loci is proposed, based on analysis of correlated trait complexes. For a given set of QTs, the broad sense heritability attributed to a QT locus (QTL) (say, A/a) is an increasing function of the number of traits. Thus, for some traits x and y, H(xy)2(A/a) &gt; or = H(x)2(A/a). The last inequality holds even if y does not depend on A/a at all, but x and y are correlated within the groups AA, Aa and aa due to nongenetic factors and segregation of genes from other chromosomes. A simple relationship connects H2 (both in single trait and two-trait analysis) with the expected LOD value, ELOD = -1/2N log(1-H2). Thus, situations could exist that from the inequality H(xy)2(A/a) &gt; or = H(x)2(A/a) a higher resolution is provided by the two-trait analysis as compared to the single-trait analysis, in spite of the increased number of parameters. Employing LOD-score procedure to simulated backcross data, we showed that the resolution power of the QTL mapping model can be elevated if correlation between QTs is taken into account. The method allows us to test numerous biologically important hypotheses concerning manifold effects of genomic segments on the defined trait complex (means, variances and correlations).
IDENTITY COEFFICIENTS IN FINITE POPULATIONS. I. EVOLUTION OF IDENTITY COEFFICIENTS IN A RANDOM MATING DIPLOID DIOECIOUS POPULATION
Authors: Chevalet C , Gillois M , Nassar R F 
Published: April 2021

ABSTRACT
Properties of identity relation between genes are discussed, and a derivation of recurrent equations of identity coefficients in a random mating, diploid dioecious population is presented. Computations are run by repeated matrix multiplication. Results show that for effective population size (Ne) larger than 16 and no mutation, a given identity coefficient at any time t can be expressed approximately as a function of (1—f), (1—f)3 and (1—f)6, where f is the mean inbreeding coefficient at time t. Tables are presented, for small Ne values and extreme sex ratios, showing the pattern of change in the identity coefficients over time. The pattern of evolution of identity coefficients is also presented and discussed with respect to N eu, where u is the mutation rate. Applications of these results to the evolution of genetic variability within and between inbred lines are discussed.
INCREASED SPONTANEOUS MITOTIC SEGREGATION IN MMS-SENSITIVE MUTANTS OF SACCHAROMYCES CEREVISIAE
Authors: Prakash Satya , Prakash Louise 
Published: April 2021

ABSTRACT
Methyl methanesulfonate (MMS)-sensitive mutants of Saccharomyces cerevisiae belonging to four different complementation groups, when homozygous, increase the rate of spontaneous mitotic segregation to canavanine resistance from heterozygous sensitive (canr/+) diploids by 13- to 170-fold. The mms8—1 mutant is MMS and X-ray sensitive and increases the rate of spontaneous mitotic segregation 170-fold. The mms9—1 and mms13—1 mutants are sensitive to X rays and UV, respectively, in addition to MMS, and increase the rate of spontaneous mitotic segregation by 13-fold and 85-fold, respectively. The mutant mms21—1 is sensitive to MMS, X rays and UV and increases the rate of spontaneous mitotic segregation 23-fold.
PROTOPLASMIC INCOMPATIBILITY AND CELL LYSIS IN PODOSPORA ANSERINA. I. GENETIC INVESTIGATIONS ON MUTATIONS OF A NOVEL MODIFIER GENE THAT SUPPRESSES CELL DESTRUCTION
Authors: Labarere Jacques , Bernet Jean 
Published: April 2021

ABSTRACT
In Podospora anserina, protoplasmic incompatibility (a phenomenon that prevents heterokaryon formation because of the destruction of the fused cells) can be studied in homokaryotic strains that combine nonallelic incompatibility genes or carry mutations at the lys loci. In these strains cell destruction occurs early in development and is associated with an arrest of growth.—From the self-lysing strains lysA(1) and RV (R and V are nonallelic incompatibility genes) mutations have been selected that suppress the self-lysing trait, i.e., that prevent cell destruction and remove growth inhibition. Some of them were derived from a novel modifier locus, modC, located near the mating-type locus.—In C/D and C/E incompatibility systems, modC mutations, which per se have no obvious effect, were considered in addition to mutations in the previously identified modifier loci, modA and modB. The demonstration of a functional interdependence among the three mod genes suggested that modC is not the structural gene for the protease associated with cell lysis, but is involved, like modA and modB, in its control.—All three modC mutant strains investigated exhibit defects in the formation of protoperithecia, suggesting that the modC gene function is essential to the occurrence or development of the female organs. This is the third argument that supports the hypothesis (Boucherie, Bégueret and Bernet 1976) that protoplasmic incompatibility and female organ formation might be related phenomena.
AGE-CORRELATED CHANGES IN EXPRESSION OF MICRONUCLEAR DAMAGE AND REPAIR IN PARAMECIUM TETRAURELIA
Authors: Rodermel Steven R , Smith-Sonneborn Joan 
Published: April 2021

ABSTRACT
In Paramecium, age is defined as the number of mitotic divisions which have elapsed since the previous cross-fertilization (conjugation) or self-fertilization (autogamy). As the mitotic interval between fertilizations increases, the percentage of nonviable progeny clones increases. In the current study, resolution of conflicting previous reports on the pattern of increase of death and reduced viability in progeny from aging parent cells is found. Some exautogamous clones exhibit a high mortality at young clonal ages, others show no mortality throughout their life span, but most (73%) show an abrupt increase in the percent death and reduced viability in progeny from cells 50-80 fissions old.
Ultraviolet-irradiation-induced micronuclear mutations, repairable by photoreactivation, increased with increased clonal age when monitored by percent death and reduced viability of exautogamous progeny of irradiated cells. Loss of dark repair is considered a contributor to the increased expression of micronuclear mutations with increased clonal age.
PHYLOGENETIC RELATIONSHIPS AMONG DROSOPHILA LONGICORNIS, DROSOPHILA PROPACHUCA AND DROSOPHILA PACHUCA, A TRIAD OF SIBLING SPECIES
Authors: Wasserman Marvin , Koepfer H Roberta 
Published: April 2021

ABSTRACT
Drosophila longicornis, D. propachuca and D. pachuca comprise a triad of sibling species. They are morphologically indistinguishable, sympatric forms that, under laboratory conditions, are capable of exchanging genes through the production of fertile F1 females. However, we have no evidence for introgressive hybridization in nature. The chromosomal constitution of our strains indicates that the ancestral species had the Primitive E gene sequence, and therefore differed from the standard repleta sequence by being Xabc; 2abcg; 3abc. This Primitive E sequence is found in both D. propachuca and D. longicornis. Each of these two species has its own unique rearrangements. D. pachuca is a derived species, which evolved from propachuca. It is cytologically more advanced and has, as its most primitive gene arrangement, one of the more advanced arrangements found in propachuca.
INBREEDING IN POPULATIONS WITH OVERLAPPING GENERATIONS
Authors: Johnson D L 
Published: April 2021

ABSTRACT
An inbreeding matrix is defined for populations with overlapping generations. In the short term it can be expressed in terms of a matrix specifying the passage of genes between the different age groups (and sexes) and a diagonal matrix whose elements depend on the number of individuals in each age group. Formulae for the inbreeding effective number are derived using matrix theory. A comparison is made between the inbreeding coefficients predicted by this theory and those obtained by assuming a uniform rate of inbreeding from the outset, and these in turn are compared with the exact inbreeding coefficients.
GENETICS OF EXTRACELLULAR PROTEASE PRODUCTION IN SACCHAROMYCOPSIS LIPOLYTICA
Authors: Ogrydziak David M , Mortimer Robert K 
Published: April 2021

ABSTRACT
Mutants of Saccharomycopsis lipolytica with reduced ability to produce zones of clearing on skim-milk agar plates were isolated and their properties studied. For 18 mutants it was possible to score unambiguously segregants of crosses between these mutants and wild type for extracellular protease production. These mutants all produce reduced levels of extracellular protease in liquid culture. The mutations are recessive and are in nuclear genes. The 18 mutations define 10 or 11 complementation groups, no two of which are closely linked. Mutants in four of the complementation groups also produced reduced levels of extracellular RNAse, and the reduced levels of extracellular protease and RNAse production segregate together. Five of the mutants exhibited reduced mating frequency, and one mutant was osmotic remedial for extracellular protease production. These results demonstrate that many genes can affect extracellular protease production. Besides mutations in the structural gene and in regulatory genes, mutations are likely to be in genes involved in steps common to the production of several extracellular enzymes or in genes coding for cell wall or membrane components necessary for extracellular enzyme production.
CHROMOSOMAL ANALYSIS OF DDT-RESISTANCE IN A LONG-TERM SELECTED POPULATION OF DROSOPHILA MELANOGASTER
Authors: Dapkus D , Merrell D J 
Published: April 2021

ABSTRACT
The genetic basis of DDT-resistance was studied in a population of Drosophila melanogaster. This population was unique in that it had been continually selected for DDT-resistance since 1952 and had achieved a very high level of resistance. The genetic basis of resistance was studied by means of a chromosomal analysis. Fifteen combinations of resistant and control chromosomes were tested using a time-based DDT test. The analysis of the data showed that resistance was multifactorial with each of the three major chromosomes involved. Dominant and recessive second and third chromosome effects were found to be much more important than those of the first chromosome, which had no detectable recessive effects. Second and third chromosome resistance genes showed incomplete dominance. The average dominance of the second chromosome was much less than that of the third chromosome. These large-scale differences between chromosomes' effects and average dominance may indicate that a small number of resistance genes are involved. Two significant interactions between chromosomes were found. Scaling difficulties make the interactions difficult to interpret without further data. It seems possible that positive interactions between resistance have been developed by the long-term directional selection in this population.
AN ANALYSIS OF MULTI-ALLELIC DATA
Authors: Watterson G A 
Published: April 2021

ABSTRACT
Some multi-allelic data obtained by COYNE (1976) and by SINGH, LEWONTIN and FELTON (1976) are analyzed for their compatibility with the neutral alleles theory. It is found that strict neutrality appears not to be the case, but that if further alleles were to be distinguished in the samples, neutrality could become a possible explanation.
AN ANALYSIS OF MALE-RECOMBINATION ELEMENTS IN A NATURAL POPULATION OF DROSOPHILA MELANOGASTER IN SOUTH TEXAS
Authors: Matthews Kathleen A , Hiraizumi Yuichiro 
Published: April 2021

ABSTRACT
Genomes from a group of Drosophila melanogmter collected from a natural population at San Benito, South Texas, in March of 1975 were analyzed for the presence of male-recombination elements. All three autosomes and both sex chromosomes were examined, with emphasis placed on the two major autosomes, the second and third chromosomes. In samples of 16 second and 16 third chromosomes, at least half, but not all, of each were found to carry male-recombination elements. It is suggested, although the data are not conclusive, that some of the fourth, X, and Y chromosomes might also be associated with male-recombination elements.—When a male-recombination element, or elements, was located in the second chromosome, relatively more male recombination was induced in the second than in the third chromosome. This situation was reversed when the element(s) was located in the third chromosome.—Distortion of transmission frequency, one of the characteristics of previously studied second chromosome lines associated with male recombination, was confirmed for these second chromosomes that carried male-recombination elements. Similar, but less pronounced, distortion was observed for the third chromosome lines that carried male-recombination elements.
ALCOHOL DEHYDROGENASE MUTANTS OF CHINESE HAMSTER SOMATIC CELLS RESISTANT TO ALLYL ALCOHOL
Authors: Thirion Jean-Paul , Talbot Brian 
Published: April 2021

ABSTRACT
Alcohol dehydrogenase (alcohol: NAD oxidoreductase, E.C. 1.1.1.1.) mutants of Chinese hamster somatic cells were isolated as resistant to allyl alcohol (ALLR). The ALLR phenotypes of the mutant clones were reproducible with high fidelity and stable over long intervals of growth in the absence of the selecting drug. Several mutants, Adh-1, Adh-2, Adh-9 and Adh-13, resistant to allyl alcohol were characterized. They have between 15 and 40% of the alcohol dehydrogenase activity of the wild-type cell lines. Cell-cell hybridization experiments using Adh-1 and wild-type Chinese hamster cells indicate that resistance to allyl alcohol is recessive to the wild-type allele. This phenotype is therefore a useful marker to analyze gene segregation of somatic cell mutations and to study the expression of the genes involved in the metabolism of ethanol in mammalian cells.
GENETIC LENGTHS AND BREAK POINTS IN TWELVE CHROMOSOMES OF GOSSYPIUM HIRSUTUM INVOLVED IN TEN RECIPROCAL TRANSLOCATIONS
Authors: Menzel Margaret Y , Brown Meta S 
Published: April 2021

ABSTRACT
Chromosome configurations were recorded in about 5500 pollen mother cells (PMC's) in 2n and 2n-1 (missing the intact A-genome chromosome) heterozygotes of ten reciprocal translocations involving six A-genome chromosomes (H1, H2, H3, H4, H6 and H7) and six D-genome chromosomes (H14, H15, H16, H19, H20 and H21) of Gossypium hirsutum. From these records, chiasma frequencies at each of six positions were determined for nine translocations and at two positions for one. These frequencies were used to calculate recombination frequencies in different chromosome regions, and from these distances the breakpoints in 15 chromosome arms were mapped relative to each other and to their respective centromeres, insofar as the data permitted. The karyotype so derived for twelve chromosomes is in reasonably good agreement with data from genetic mapping, telosome and monosome mapping, and the mitotic idiogram.
CHARACTERIZATION OF A MUTATION IN YEAST CAUSING NONRANDOM CHROMOSOME LOSS DURING MITOSIS
Authors: Liras Paloma , McCusker John , Mascioli Stephen , Haber James E 
Published: April 2021

ABSTRACT
Diploid strains of the yeast Saccharomyces cerevisiae homozygous for a recessive chromosome loss mutation (chl) exhibit a high degree of mitotic instability. Cells become monosomic for chromosome III at a frequency of approximately one percent of all cell divisions. Chromosome loss at this high frequency is also found for chromosome I, and at lesser frequencies for chromosomes VIII and XVI. In contrast, little or no chromosome loss is found for six other linkage groups tested (II, V, VI, VII, XI and XVII). The chl mutation also induces a ten-fold increase in both intergenic and intragenic mitotic recombination on all ten linkage groups tested. The chl mutation does not cause an increase in spontaneous mutations, nor are mutant strains sensitive to UV or γ irradiation. The effects of chl during meiosis are observed primarily in reduced spore viability. A decrease in chromosome III linkage relationships is also found.
GENE DUPLICATION IN SACCHAROMYCES CEREVISIAE
Authors: Hansche P E , Beres V , Lange P 
Published: April 2021

ABSTRACT
Five indepdendent duplications of the acid-phosphatase (aphtase) structural gene (acp1) were recovered from chemostat populations of S. cerevisiae that were subject to selection for in vivo hyper-aphtase activity. Two of the duplications arose spontaneously. Three of them were induced by UV. All five of the duplication events involved the transpositioning of the aphtase structural gene, acp1, and all known genes distal to acp1 on the right arm of chromosome II, to the terminus of an arm of other unknown chromosomes. One of the five duplicated regions of the right arm of chromosome II was found to be transmitted mitotically and meiotically with very high fidelity. The other four duplicated regions of the right arm of chromosome II were found to be unstable, being lost at a rate of about 2% per mitosis. However, selection for increased fidelity of mitotic transmission was effective in one of these strains. No tandem duplications of the aphtase structural gene were found.
NONESSENTIAL SEQUENCES, GENES, AND THE POLYTENE CHROMOSOME BANDS OF DROSOPHILA MELANOGASTER
Authors: Young Michael W , Judd B H 
Published: April 2021

ABSTRACT
From earlier work, there appears to be an underlying one-to-one correspondence of polytene chromosome bands and complementation groups within a sizeable, continuous X-chromosome segment, 3A1-3C7 (Judd, Shen and Kaufman 1972; Lefevre and Green 1972). However, most of the data supporting this one-to-one relation of bands and genes were gathered from mutants that upset vital functional units, thus leading to lethality. Among this series of mutants, only four loci, zeste, white, roughest and verticals, have no known lethal alleles. If phenotypic changes less drastic than lethality result from the loss of other chromosomal segments, they probably would not have been recognized in the earlier studies.—We report here some chromosomal sequences localized in 3A, 3B, and 3C whose loss effects no lethal change in the development of the animal. A portion of the 3A3-3A4 region can be disrupted in a nonlethal fashion, yet this sequence does not seem to be a part of either the zeste locus or l(1)zw1, which are known to be located in these bands. Two more complementation groups have been discovered that have no lethal alleles and map to 3B4-3B6; a third falls within 3B1-2. The loss of a sequence in 3C2-3 is tolerated without any genetically observable effect. Between 3C7 and the boundary of 3D there is at least one more sequence that behaves in this manner.—The discovery of these units, which are not allelic to any of the loci previously known, makes it clear that division 3B contains more genes (i.e., complementation groups) than polytene chromosome bands, while portions of 3A and 3C seem to have no functional significance. Accordingly many polytene chromosome bands may be composites of several complementing functional units. This investigation also indicates that there are chromosomal segments that are seemingly dispensible and thus function in a manner that is difficult or impossible to define with available methods.
DNA DISTRIBUTION IN SPERMATID NUCLEI OF NORMAL AND SEGREGATION DISTORTER MALES OF DROSOPHILA MELANOGASTER
Authors: Hauschteck-Jungen E , Hartl D L 
Published: April 2021

ABSTRACT
Using the DNA-specific dye BAO [2,5-bis-(4′-aminophenyl-(1′)]-1,3,4-oxadiazol), we have examined spermiogenesis in wild-type males of Drosophila melanogaster and in males carrying various combinations of the Sd and Rsp mutations involved in segregation distortion. Wild-type strains, even those newly collected from nature, are heterogeneous with respect to the incidence of spermiogenic abnormalities, principally in having a variable number of spermatid nuclei per cyst that fail to undergo complete elongation. Among segregation distorter males, Rsp/Rsp homozygotes have the greatest incidence of nuclear nonelongation or incomplete elongation, Rsp/Rsp + heterozygotes are intermediate, while Rsp +/Rsp + homozygotes have the least amount of abnormality. Indeed, Sd Rsp +/Sd + Rsp + males have significantly fewer spermiogenic aberrations than do wild-type strains.
INDUCED RESISTANCE TO 6-METHYLPURINE AND CYCLOHEXIMIDE IN TETRAHYMENA. II. VARIATION WITHIN VEGETATIVE CULTURES OF MICRONUCLEATE T. THERMOPHILA AND AMICRONUCLEATE T. PYRIFORMIS
Authors: Byrne Bruce C 
Published: April 2021

ABSTRACT
Resistance to 6-methylpurine and cycloheximide has been induced in both the micronucleate species Tetrahymena thermophila and the amicronucleate species T. pyriformis. Resistance follows only after mutagen treatment and vegetative growth. The frequencies with which resistant variants are induced and the independence of mutagenesis and selection are demonstrated. All evidence is consistent with the hypothesis that macronuclear subunits are assorting in both species during vegetative growth to produce new phenotypes among subclones.
BROMODEOXYURIDINE-INDUCED MUTATIONS IN SYNCHRONOUS CHINESE HAMSTER CELLS: TEMPORAL INDUCTION OF 6-THIOGUANINE AND OUABAIN RESISTANCE DURING DNA REPLICATION
Authors: Burki H John , Aebersold Paul M 
Published: April 2021

ABSTRACT
Mutations were induced in synchronous Chinese hamster cells by bromodeoxyuridine (BUdR) incorporated into cells for one-hour periods in the cell cycle. There was a very pronounced temporal dependence during the first half of the DNA synthesis period for the induction of damage leading to 6-thioguanine (6TG) and ouabain resistance. No mutants above background were induced by exposure to BUdR in G1 and G2 cells, and very few mutants were induced in the latter part of the DNA synthesis period. The peak for the induction of 6TG resistance occurs at about two hr in the DNA synthesis period; one hour later there is a peak for the induction of ouabain resistance. Both peaks occur before the time of maximum incorporation of BUdR into DNA. These results suggest that the mutagenesis by BUdR is associated with at least two nuclear genes, which replicate at two hr and three hr in the DNA synthesis period.