bluuebunny/crossref_metadata_2025_split huggingface dataset:
MAPPING CHROMOSOMAL GENES OF SACCHAROMYCES CEREVISIAE USING AN IMPROVED GENETIC MAPPING METHOD
Authors: Wickner Reed B 
Published: April 2021

ABSTRACT
A triploid (3n) strain of Saccharomyces cereuisiae was constructed carrying a standard marker on each of chromosomes I through XVII in the ——/+J+ configuration. This is called a "supertriploid." Meiotic spores from this strain (n + ∼ n/2) were mated with a haploid (n) carrying an unmapped mutation. Meiotic analysis of each zygote clone (2n + ∼ n/2) produced in this way resulted in elimination of an average of 4.2 chromosomes as the possible location of the unmapped marker. The distribution of extra chromosomes in the 2n + ∼ n/2) strains was nearly random. Meiotic segregrants of these crosses carrying the unmapped mutation in the -/+ configuration were then crossed with multiply marked haploid strains to further narrow the possible location of the unmapped mutation to a single chromosome. Scoring of markers by complemention tests was simplified by mating spore clones with mixtures of a and α strains, each pair carrying the same set of markers. Using this new, more rapid method ("supertriploid mapping"), eight genes required for the maintenance of the killer plasmid were located on the genetic map of S. cerevisiae.
GENETIC VARIATION IN AMOUNT OF SALIVARY AMYLASE IN THE BANK VOLE, CLETHRIONOMYS GLAREOLA
Authors: Hjorth J Peter , Meisler Miriam , Nielsen J TØnnes 
Published: April 2021

ABSTRACT
Several investigated bank vole populations are polymorphic for the number of salivary amylase loci, and individual chromosomes may carry one, two or three linked amylase structural genes. In the present study, we have used bank vole stocks homozygous for different chromosomes to investigate the relationship between amylase production and gene number. By measuring the amylase activity in parotid glands and the percentage of amylase protein in saliva, we have been able to demonstrate that the amount of salivary amylase is directly proportional to the proposed gene number. The paper also describes the allele, Amysu, which codes for a heat-labile salivary amylase. The relative amounts of the heat-labile isozyme have been determined in different hetero-zygotes containing this allele, and these results also support the multiple locus model. Finally, a stock devoid of salivary amylase activity was established. Animils from this strain have, however, a protein in the parotid glands and in saliva that is very similar to amylase in molecular weight, amino acid composition and in its binding to glycogen and cyclohepta-amylose. In genetic crosses, the protein segregates as an amylase allele. Therefore, this protein, encoded by the functionally null alleleAmyN, may represent an incorrectly processed amylase precursor.
ENZYME POLYMORPHISM AND CYCLIC PARTHENOGENESIS IN DAPHNIA MAGNA. II. HETEROSIS FOLLOWING SEXUAL REPRODUCTION
Authors: Young J P W 
Published: April 2021

ABSTRACT
Cyclical parthenogenesis exaggerates the force of selection relative to recombination and will therefore enhance interlocus effects. Observations of electrophoretic variation in a natural population of Daphnia magna Straus (Crustacea: Cladocera) are interpreted in this light. Sexual reproduction led to Hardy-Weinberg equilibrium, but heterozygote excesses rapidly developed at each of three observed loci during subsequent parthenogenesis. Homozygote fecundity was often lower than that of heterozygotes; this may have been the cause of some of the observed frequency changes. The superior fitness of the enzyme heterozygotes does not imply that selection was necessarily acting on the enzyme loci themselves, since apparent heterosis is the expected result of linkage disequilibrium.
A STUDY OF LINKAGE DISEQUILIBRIUM IN BRITISH POPULATIONS OF DROSOPHILA SUBOBSCURA
Authors: Charlesworth B , Charlesworth D , Loukas M 
Published: April 2021

ABSTRACT
Data have been obtained concerning the genetic content of samples of O chromosomes from three British populations, and J chromosomes from one population, of Drosophila subobscura. Some improvements to the genetic map of the O and J chromosomes have been made. Allele frequencies at the loci studied do not show much geographical variation, except where associations with geographically varying gene arrangements distort the picture. Striking nonrandom associations between alleles at three enzyme loci and closely linked O chromosome gene arrangements are present. Some historical explanation for these associations cannot at present be ruled out, but it is clear that a very high degree of genetic differentiation must exist between different gene arrangements in this species. There is no convincing direct evidence for linkage disequilibrium between pairs of enzyme loci, although there is a significant association between close linkage and a high value of the linkage disequilibrium measure. This suggests that there may be disequilibria between closely linked enzyme loci that are too small to be individually detectable. These results are in broad agreement with those reported by workers on other Drosophila species. At present there appears to be no evidence to support the concept that selection is sufficiently strong at individual enzyme loci to produce a high degree of nonrandom associations. (FRANKLIN and LEWONTIN 1970).
MUTANTS OF TETRAHYMENA THERMOPHILA WITH TEMPERATURE-SENSITIVE FOOD VACUOLE FORMATION. I. ISOLATION AND GENETIC CHARACTERIZATION
Authors: Suhr-Jessen Peter B , Orias Eduardo 
Published: April 2021

ABSTRACT
Germ-line mutants have been isolated in Tetrahymena thermophila that have recessive, temperature-sensitive defects in phagocytosis. Nitrosoguanidine-mutagenized cells were induced to undergo cytogamy, and clones were isolated that were unable to form food vacuoles after two days of growth at 39°. Most of the mutants belong to a single complementation group, designated vacA. They have defects in oral development—not in phagocytosis per se—that are undetectable under light microscopy. One fertile mutant, phenotypically indistinguishable from the vacA group, has its vac mutation(s) restricted to the macronucleus, and it is a heterokaryon for two other markers. This clone probably resulted from a failure of the two gametic nuclei to fuse after nor,mal exchange. Two additional mutants were studied, but their sterility prevented a full genetic analysis. One of these clones has a rudimentary oral apparatus and defective contractile vacuole pores; both defects may be determined by the same mutation. The other clone has a structurally normal oral apparatus and may be defective in phagocytosis per se.——The induction and characterization of germ-line mutations that affect oral development open the way for the genetic dissection of the morphogenesis of a complex eukaryotic organelle, and make available additional useful mutants for the study of nutrition and transmembrane active transport.
HYBRID DYSGENESIS IN DROSOPHILA MELANOGASTER: MORPHOLOGICAL AND CYTOLOGICAL STUDIES OF OVARIAN DYSGENESIS
Authors: Schaefer Ruth E , Kidwell Margaret G , Fausto-Sterling Anne 
Published: April 2021

ABSTRACT
A type of intraspecific hybrid sterility, between two strains of Drosophila melanogaster, referred to as GD (gonadal dysgenesis) sterility, is observed when females from a type of strain called M are crossed with males from a second type called P. Absence of egg-laying is characteristic of female GD sterility and its manifestation is conditional on high developmental temperatures. Morphological and cytological studies of GD sterile females are described. These individuals were normal in body size and external appearance. No defects in sperm storage were observed. Both adult and larval ovaries were drastically reduced in size in comparison with control ovaries. This ovarian dysgenesis was sometimes unilateral, but more frequently it was bilateral, particularly in females developing at the highest test temperature. The ovarioles of dysgenic ovaries contained no vitellaria; the germaria lacked any cells resembling the cystocyte clusters of normal ovaries. I t is concluded that sterility results from an early blockage in ovarian development, rather than from atrophy of previously developed structures. Possible mechanisms for this developmental arrest are discussed.
CHROMOSOMAL LOCATION OF TWO MITOCHONDRIAL MALATE DEHYDROGENASE STRUCTURAL GENES IN ZEA MAYS USING TRISOMICS AND B-A TRANSLOCATIONS
Authors: McMillin David E , Roupakias D G , Scandalios John G 
Published: April 2021

ABSTRACT
Maize mitochondrial malate dehydrogenase is coded by four genetic loci, Mdhl, Mdh.2, Mdh3 and Mdh4. Two of the four loci have been located on the long arm of chromosome 6, using trisomic analysis and B-A translocations.
EVOLUTIONARY CONSERVATION OF EQUINE Gc ALLELES AND OF MAMMALIAN Gc/ALBUMIN LINKAGE
Authors: Weitkamp Lowell R , Allen Peter Z 
Published: April 2021

ABSTRACT
Ancient origin of the equine vitamin D binding protein (Gc) polymorphism is suggested by the finding of two alleles, GcF and Gcs, in each of three equine subgenera, Equus, Asinus and Hippotigris. The equine Gc and albumin loci are closely linked (lod score = 6). Although no recombinants were observed, the data are not inconsistent with a map distance similar to the 2 centimorgans reported for the human albumin/Gc linkage relationship. Gametic association between the GcF and AlbF alleles appears probable in the American Standardbred horse, perhaps as a result of population structure. Since Gc and albumin are both polymorphic in rodents and possibly other orders, this linkage group will be useful for studies of the evolution of mammalian linkage groups, as well as for a comparison of meiotic recombination frequencies and linkage disequilibria in different species.
DELETIONS GENERATED BY THE TRANSPOSON Tn10 IN THE srl recA REGION OF THE ESCHERICHIA COLI K-12 CHROMOSOME
Authors: Csonka LÁszlÓ N , Clark Alvin J 
Published: April 2021

ABSTRACT
A negative regulatory gene for the srl operon (srlR) was recognized by the characteristics of an insertion mutation generated by the transposon TnlO determining tetracycline resistance. This finding is discussed in light of previous hypotheses on the regulation of the srl genes, which mediate metabolism of glucitol (i.e, sorbitol). Mapping showed that the order of genes in this region is: srlR srlD srlC recA alaS. Using two different methods, five mutations of both srl and recA were detected. The phenotype conferred by these mutations, UV sensitivity and extreme recombination deficiency, is characteristic of standard recA point mutants. Three of the mutations were deletions that also removed the genes for tetracycline resistance of the nearby transposon. A fourth mutation ended at a distance from Tn10 sufficient to allow separation of the two by recombination following P1 transduction; our tests did not allow US to conclude whether this mutation was an inversion or a deletion. The fifth mutation was a deletion that seemed to end immediately adjacent to the boundary of Tn10. proximal to recA. Mechanisms for the generaticn of these srl recA mutations are discussed.
GENETIC ANALYSIS OF GAMMA-RAY MUTAGENESIS IN YEAST. II. ALLELE-SPECIFIC CONTROL OF MUTAGENESIS
Authors: McKee Richard H , Lawrence Christopher W 
Published: April 2021

ABSTRACT
We find that partially different sets of gene functions are required for the production of different kinds of mutations induced by 6OCo γ rays in Saccharomyces cereuisiae. This observation is very similar to others made previously with respect to UV mutagenesis (LAWRENCE and CHRISTENSEN 1978a,b, 1979) and confirms the conclusion that such distinctive patterns of genetic control reflect properties of the test alleles and their genetic locations, rather than the kinds of lesions required to revert them. The data also support the model of mutagenic repair outlined in the first paper of this series (MCKEE and LAWRENCE 1979), in which partially different sets of gene functions are required for the production of different kinds of mutations, the formation of mutations at different genetic sites and the induction of mutations by different mutagens.
SITE-SPECIFIC INSTABILITY IN DROSOPHILA MELANOGASTER: THE ORIGIN OF THE MUTATION AND CYTOGENETIC EVIDENCE FOR SITE SPECIFICITY
Authors: Lim J K 
Published: April 2021

ABSTRACT
During a study of delayed mutations, an unstable X chromosome (UC) was detected. Spontaneous X-linked recessive lethal mutations were detected in 34 of 993 sperm sampled from 50 males carrying this chromosome. All but three of the 34 lethals originated as clusters in three of the 50 males Cytogenetic and complementation analyses revealed 14 intrachromosomal rearrangements: ten inversions, two reverse repeats, one deficiency and one transposition. Eight of the 14 rearrangements have one break in the 6F1-2 doublet and two rearrangements have a break in 6F1-5 of the X chromosome. The remaining four rearrangements have in addition to the aberrations a lethal point mutation between 6F1 and 6F5. Though each of the lethal lines was established from a single lethal-bearing female, chromosome polymorphism is evident in 17 of the 18 lines having rearrangements, with certain aberrations recurring in several lines. The lethal mutations revert frequently to the nonlethal state, and cytological evidence indicates that more than one mutational event may occur at the unstable locus of the chromosome during one generation. Two lethal lines had more than one type of chromosome rearrangement sharing a common breakpoint. These observations are consistent with the view that the instability in the Uc lines is caused by a transposable element capable of site-specific chromosome breaks and perpetual generation of mutations. The mutagenic and genetic properties of transposable elements can be related to the two-mutation theory of KNUDSON (1971) for cancer initiation.
TOWARDS A GENETIC THEORY FOR THE EVOLUTION OF THE SEX RATIO
Authors: Uyenoyama Marcy K , Bengtsson Bengt Olle 
Published: April 2021

ABSTRACT
Present address: Department of Zoology, University of Texas, Austin, Texas 78712.—Permanent address: Institute 0f Genetics, University of Lund, S-223 62 Lund, Sweden.
HERITABILITY OF POLYCHOTOMOUS CHARACTERS
Authors: Gianola Daniel 
Published: April 2021

ABSTRACT
Characters with phenotypic expression consisting of a response in one of several mutually exclusive and exhaustive categories are considered. Formulae relating heritability in the discrete, outward scale to heritability in underlying normal and exponential scales are presented. For the normal case with two response categories, results reduce to the well-known formula for heritability of binary traits.
A SUPPRESSOR OF MATING-TYPE LOCUS MUTATIONS IN SACCHAROMYCES CEREVISIAE: EVIDENCE FOR AND IDENTIFICATION OF CRYPTIC MATING-TYPE LOCI
Authors: Rine Jasper , Strathern Jeffrey N , Hicks James B , Herskowitz Ira 
Published: April 2021

ABSTRACT
A mutation has been identified that suppresses the mating and sporulation defects of all mutations in the mating-type loci of S. cereuisiae. This suppressor, sir1-1, restores mating ability to matαl and matα2 mutants and restores sporulation ability to matα2 and mata1 mutants. MATa sir1-1 strains exhibit a polar budding pattern and have reduced sensitivity to α-factor, both properties of a/α diploids. Furthermore, sir1-1 allows MATa/MATa, matα1/matα1, and MATα/MATα strains to sporulate efficiently. All actions of sir1-1 are recessive to SIR1. The ability of sir1-1 to supply all functions necessary for mating and sporulation and its effects in a cells are explained by proposing that sir1-1 allows expression of mating type loci which are ordinarily not expressed. The ability of sir1-1 to suppress the matαl-5 mutation is dependent on the HMa gene, previously identified as required for switching of mating types from a to α. Thus, as predicted by the cassette model, HMa is functionally equivalent to MATα since it supplies functions of MATα. We propose that sir1-1 is defective in a function, Sir ("Silent-information regulator"), whose role may be to regulate expression of HMa and HMα.
RARE-CELL FUSION EVENTS BETWEEN DIPLOID AND HAPLOID STRAINS OF THE SEXUALLY AGGLUTINATIVE YEAST HANSENULA WINGEI
Authors: Crandall Marjorie , Caulton Joan H 
Published: April 2021

ABSTRACT
Diploids of the yeast Hansenula wingei are nonagglutinative and do not form zygotes in mixed cultures with either sexually agglutinative haploid mating type. However, a low frequency of diploid x haploid cell fusions (about 10-3) is detectable by prototrophic selection. This frequency of rare diploid x haploid matings is not increased after the diploid culture is induced for sexual agglutination. Therefore, we conclude that genes that repress mating are different from those that repress sexual agglutination.——Six prototrophs isolated from one diploid x haploid cross had an average DNA value (¼g DNA per 108 cells) of 6.19, compared to 2.53 and 4.35 for the haploid and diploid swains, respectively. Four prototrophs were clearly cell-fusion products because they contained genes from both the diploid and the haploid partners. However, genetic analysis of the prototrophs yielded results inconsistent with triploid meiosis; all six isolates yielded a 2:2 segregation for the mating-type alleles and linked genes.——Mitotic segregation of monosomic (2n-1) cells lacking one homolog of the chromosome carrying the mating-type locus is proposed to explain the rare production of sexually active cells in the diploid cultures. Fusion between such monosomic cells and normal haploids is thought to have produced 3n-1 cells, disomic for the chromosome carrying the mating-type locus. We conclude that in the diploid strain we studied, the physiological mechanisms repressing sexual agglutination and conjugation function efficiently, but events occurring during mitosis lead to a low frequency of genetically altered cells in the population.
POLYMORPHISMS, LINKAGE AND MAPPING OF FOUR ENZYME LOCI IN THE FISH GENUS XIPHOPHORUS (POECILIIDAE)
Authors: Morizot Donald C , Siciliano Michael J 
Published: April 2021

ABSTRACT
Electrophoretic variants at four additional enzyme loci—two esterases (Est-2, Est-3), retinal lactate dehydrogenase (LDH-1) and mannose phosphate isomerase (MPI)-among three species and four subspecies of fish of the genus Xiphophorus were observed. Electrophoretic patterns in F1 hybrid heterozygotes confirmed the monomeric structures of MPI and the esterases and the tetrametric structure of LDH in these fishes. Variant alleles of all four loci displayed normal Mendelian segregation in backcross and F2 hybrids. Recombination data from backcross hybrids mapped with Haldane's mapping function indicate the four loci to be linked as Est-2—0.43—Est-3—0.26—LDH-1—O.19—MPI. Significant interference was detected and apparently concentrated in the Est-3 to MPI region. No significant sex-specific differences in recombination were observed. This group (designated linkage group 11) was shown to assort independently from the three loci of linkage group I (adenosine deaminase, glucose-6phosphate dehydrogenase, and 6-phospho-gluconate dehydrogenase) and from glyceraldehyde-3-phosphate dehydrogenase and two isocitrate dehydrogenase loci. Evidence for conservation of the linkage group, at least in part, in other vertebrate species is presented.
ADULT TRIPLOIDS IN A RAINBOW TROUT FAMILY
Authors: Thorgaard Gary H , Gall Graham A E 
Published: April 2021

ABSTRACT
Six triploid individuals were found in a full-sib family of 11 adult rainbow trout (Salmo gairdneri) from a domesticated hatchery stock. The triploid individuals were normal in size and external appearance, had underdeveloped gonads, and showed no evidence of 3n/2n chimerism or mosaicism. XXY triploids were males, suggesting that the Y chromosome is male determining in trout. Because they may avoid production losses associated with sexual maturation in normal fish, triploid trout and salmon could potentially be useful in fish culture.
THE GENETIC STRUCTURE OF NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER. XIV. EFFECTS OF THE INCOMPLETE DOMINANCE OF THE IN(2LR)SM1 (Cy) CHROMOSOME ON THE ESTIMATES OF VARIOUS GENETIC PARAMETERS
Authors: Mukai Terumi 
Published: April 2021

ABSTRACT
Recent reports (MUKAI et al. 1974; KATZand CARDELLINO1978; COCKER-HAM and MUEAI 1978) have indicated that the Cy chromosome is not always dominant over its homologous chromosome with respect to viability. Thus,the genetic parameters previously estimated using viabilities determined by the Cy method are biased. In the present paper, the biases of the estimates for the polygenic mutation rate, the degree of dominance and the homozygous load are examined. The results indicate that the biases for the mutation rate and the degree ofdominance are small and that the estimate of the homozygous load relative to the average viability of the population is not biased.
EFFECTS OF THE RAD52 GENE ON RECOMBINATION IN SACCHAROMYCES CEREVISIAE
Authors: Prakash Satya , Prakash Louise , Burke William , Montelone Beth A 
Published: April 2021

ABSTRACT
Effects of the rad52 mutation in Saccharomyces cerevisiae on meiotic, γ-ray-induced, UV-induced and spontaneous mitotic recombination were studied. The rad52/rad52 diploids undergo premeiotic DNAsynthesis; sporulation occurs hut inviable spores are produced. Both intra and intergenic recombination during meiosis were examined in cells transferred from sporulation medium to vegetative medium at different time intervals. No intragenic recombination was observed at the hisl-ljhis1-315 and trp5-2/trp5-48 hetero-alleles. Gene-centromere recombination also was not observed in rad52/rad52 diploids. No γ-ray- or UV-induced intragenic mitotic recombination is seen in rad52/rad52 diploids. The rate of spontaneous mitotic recombination is lowered five-fold at the hisf -1/hisf-315 and leu1-c/leu1-12 heteroalleles. Spontaneous reversion rates of both hisf-1 and hisf-315 were elevated 10to 20 fold in rad52/rad52 diploids.—The RAD52 gene function is required for spontaneous mitotic recombination, UV- and γ-ray-induced mitotic recombination and meiotic recombination.