bluuebunny/crossref_metadata_2025_split huggingface dataset:
GENETICS OF HEMOGLOBIN IN THE DEER MOUSE, PEROMYSCUS MANICULATUS. II. MULTIPLE ALLELES AT REGULATORY LOCI
Authors: Snyder Lee R G 
Published: April 2021

ABSTRACT
Deer mice are polymorphic for electrophoretic hemoglobin phenotypes showing one, two, or three bands. Within the multibanded phenotypes, there is considerable variation in the hemoglobin partitioning, defined as the fraction of total hemoglobin made up by the secondary and tertiary bands. In subspecies sonoriensis, for example, hemoglobin partitionings range from 0.03 to 0.38. The inheritance of partitioning values is under remarkably strict genetic control. The genetic variation is additive and the narrow heritability is close to 1.0. The inheritance data can be modeled in precise detail by postulating multiple-allele polymorphisms at globin regulatory loci. Comparison of simulated versus actual inheritance data demonstrates that the so-called null structural alleles actually produce functional globins.—The genetic controls in Peromyscus may be analogous to those in primates. Unfortunately, the molecular mechanisms effecting the regulation are unknown. Different subspecies of P. maniculatus show strikingly different arrays of partitioning values, but the role of natural selection in maintaining the quantitative polymorphisms remains obscure
EXACT INBREEDING COEFFICIENTS IN POPULATIONS WITH OVERLAPPING GENERATIONS
Authors: Choy S C , Weir B S 
Published: April 2021

ABSTRACT
A theory is given that allows inbreeding coefficients to be calculated exactly for populations with overlapping generations. Emphasis is placed on providing equations well suited for computer iteration. Both monoecious and dioecious populations are considered and family size is not restricted to being Poisson. One-locus and two-locus inbreeding coefficients are evaluated, although the reader may omit the two-locus sections. The exact treatment is shown to be preferable to approximate treatments in that it applies to both early and late generations for all populations sizes. Inbreeding effective numbers found by the exact treatment are compared to various approximate numbers, and the approximate values are found to be generally very good.
ANALYSIS OF GYNANDROMORPH SURVIVALS IN DROSOPHILA MELANOGASTER INFECTED WITH THE MALE-KILLING SR ORGANISMS
Authors: Tsuchiyama Sumi , Sakaguchi Bungo , Oishi Kugao 
Published: April 2021

ABSTRACT
The effects of SRO (Sex-ratio organism; previously called SR spirochetes) infection on the viability of gynandromorphs of D. melanogaster were examined. A fraction of gynadromorphs, most of them with small areas of XO tissue, survived, but the majority were not viable when XO nuclei or cells are affected by the infecting SRO. Apparently the replacement of lethal XO nuclei or cells by adjacent XX ones does not take place. Some possibilities are discussed as to the time and the primary site of the lethal action of SRO.
ISOLATION OF A GLYCEROL-UTILIZING MUTANT OF NICOTIANA TABACUM
Authors: Chaleff R S , Parsons M F 
Published: April 2021

ABSTRACT
Although normal tobacco cell cultures cannot grow on glycerol as the sole carbon source, a spontaneous mutant cell line capable of utilizing glycerol has been isolated. Plants have been regenerated from this mutant cell line, and the results of preliminary genetic analyses are reported. The mutation appears to be specific for glycerol in that it does not alter the capability for callus growth on several other sugars tested.
RESPONSE TO SELECTION FOR MATING SPEED AND CHANGES IN GENE ARRANGEMENT FREQUENCIES IN DESCENDANTS FROM A SINGLE POPULATION OF DROSOPHILA PSEUDOOBSCURA
Authors: Spuhler Karen P , Crumpacker David W , Williams James S , Bradley Brian P 
Published: April 2021

ABSTRACT
Heritability estimates, based on 19 generations of selection for fast and slow mating speed, were not significantly different from zero at the 0.05 level in any replicate of selected lines in a population of flies descended from the Mather population in California. Only the combined heritability estimate of approximately 2% was significant. This indicated that very little additive genetic variance was present in the base population and that strong directional selection for rapid mating may have occurred in the previous history of the local population at Mather and/or during its many generations of laboratory propagation. Frequencies of third chromosome gene arrangements were monitored during the course of selection. Balancing selection, unrelated to that imposed for mating speed, and genetic drift appeared to be the major factors causing changes in chromosome frequencies. Present differences in adaptive value of third chromosome variants in nature may be associated with nonadditive effects on mating speed, as well as effects on other components of fitness.
ULTRAVIOLET-INDUCED REVERSION OF cyc1 ALLELES IN RADIATION SENSITIVE STRAINS OF YEAST. II. rev2 MUTANT STRAINS
Authors: Lawrence Christopher W , Christensen Roshan B 
Published: April 2021

ABSTRACT
The range of specificity of the rev2-1 mutation, an allele that reduces the frequency of ochre revertants induced by UV in Saccharomyces cerevisiae (Lemontt 1971a), has been investigated by examining its influence on the reversion of eleven well-defined and contrasting cyc1 mutations. We have shown, in support of a suggestion of Lemontt (1971a), that the REV2 gene product is concerned only with the reversion of ochre alleles; it plays virtually no role in the reversion of amber, missense or frameshift mutations. We have also shown that its effect is specific and confined to only some highly revertible ochre alleles. The REV2 gene product appears to enhance reversion at these sites by facilitating the conversion of two otherwise nonmutagenic photo-products into a single premutational lesion. UV-induced killing of rev2-1 strains was found to be significantly greater on fermentable rather than on nonfermentable media.
ORGANIZATION OF THE CHORION GENES OF BOMBYX MORI, A MULTIGENE FAMILY. I. EVIDENCE FOR LINKAGE TO CHROMOSOME 2
Authors: Goldsmith Marian R , Basehoar Gayle 
Published: April 2021

ABSTRACT
The chorion genes of silkmoths comprise a multigene family that codes for 50 or more highly specialized structural proteins found in the eggshell. A detailed study of the chromosomal organization of these genes was initiated, using inbred stocks of Bombyx mori as a source of electrophoretic variants for genetic markers. Chorion protein patterns were screened on thin-slab polyacrylamide isoelectric focusing gels. A wide range of polymorphism was observed between stocks. However, isoelectric focusing patterns obtained within a stock were nearly homogeneous, indicating that inbreeding has produced a high degree of homozygosis. Testcrosses were carried out to examine the linkage relationships between electrophoretic markers in four inbred stocks. One race (C108) was selected as a standard against which to compare the inheritance of the variants found in the other three stocks. Chorion markers behaved like codominant Mendelian traits in F1 crosses. A total of 15 out of 16 C108 markers cosegregated in subsequent testcrosses, indicating that they are linked. These genes were mapped to the second chromosome, using markers Gr and Y.
WITH SELECTION FOR FECUNDITY THE MEAN FITNESS DOES NOT NECESSARILY INCREASE
Authors: Pollak Edward 
Published: April 2021

ABSTRACT
A population with two alleles at one locus is considered. It is assumed that there is random mating of adults and that matings in which a particular pair of genotypes is involved may have a different mean number of offspring, or fecundity, than other types of matings. There is assumed to be no other selection. It is shown that the genotypic frequencies that maximize the mean fecundity of the population are not necessarily the same as the stable equilibrium frequencies. Thus, examples can be found for which the mean fecundity decreases from one generation to the next, and one such example is presented. An example in which there is no stable equilibrium, and the mean fecundity oscillates, is also given.
ISOLATION AND GENETIC CHARACTERIZATION OF A MUTATION AFFECTING RIBOSOMAL RESISTANCE TO CYCLOHEXIMIDE IN TETRAHYMENA
Authors: Ares Manuel , Bruns Peter J 
Published: April 2021

ABSTRACT
A dominant mutation at a new locus affecting resistance to cycloheximide has been isolated by exploiting a synergistic relationship with a previously known mutation for cycloheximide resistance in Tetrahymena. The new mutation (ChxB) was induced in a line homozygous for ChxA and was recovered from that background by a new technique termed interrupted genomic exclusion. Segregation data from the interrupted genomic exclusion suggest that ChxA and ChxB are separate, linked loci showing 30% recombination. Minimal lethal doses of cycloheximide for the four possible combinations of the wild-type and mutant alleles of these two genes are: wild type 6 µg/ml, ChxA 125 µg/ml, ChxB 10 µg/ml, ChxA-ChxB 175 µg/ml.
REGULATION OF MOUSE MAJOR URINARY PROTEIN PRODUCTION BY THE MUP-A GENE
Authors: Szoka P R , Paigen K 
Published: April 2021

ABSTRACT
A method was developed to quantitate the daily excretion of the three major urinary proteins (mups) to test which parameters of the mup phenotype are controlled by the the Mup-a gene. Electrophoretic separation of the mup proteins, followed by staining and spectrophotometric scanning was used to characterize the phenotypes of various inbred strains. The mup phenotype of a strain proved to have two components: the absolute levels and the relative proportions of the mups present in the urine. Testosterone treatment alters both components of the mup phenotype, increasing mup excretion and altering their relative proportions. The induced proteins are the same as the basal proteins as judged by electrophoretic mobility, molecular weight, and reactivity with antibody. All strains excrete all three mups when induced. The Mup-a gene appears to be a single, codominantly expressed regulatory locus that controls the induced proportions of the three proteins. However, other genes in addition to Mup-a participate in controlling the basal mup proportions, as well as individual and total mup levels before and after testosterone treatment.
THE EFFECT OF RECOMBINATION-DEFECTIVE MEIOTIC MUTANTS ON FOURTH-CHROMOSOME CROSSING OVER IN DROSOPHILA MELANOGASTER
Authors: Sandler L , Szauter Paul 
Published: April 2021

ABSTRACT
Crossing over was measured on the normally achiasmate fourth chromosome in females homozygous for one of our different recombination-defective meiotic mutants. Under the influence of those meiotic mutants that affect the major chromosomes by altering the spatial distribution of exchanges, meiotic fourth-chromosome recombinants were recovered irrespective of whether or not the meiotic mutant decreases crossing over on the other chromosomes. No crossing over, on the other hand, was detected on chromosome 4 in either wild type or in the presence of a meiotic mutant that decreases the frequency, but that does not affect the spatial distribution, of exchange on the major chromosomes. It is concluded from these observations that (a) in wild type there are regional constraints on exchange that can be attenuated or eliminated by the defects caused by recombination-defective meiotic mutants; (b) these very constraints account for the absence of recombination on chromosome 4 in wild type; and (c) despite being normally achiasmate, chromosome 4 responds to recombination-defective meiotic mutants in the same way as do the other chromosomes.
INTERACTION AMONG C, R AND Vp IN THE CONTROL OF THE Bz GLUCOSYLTRANSFERASE DURING ENDOSPERM DEVELOPMENT IN MAIZE
Authors: Dooner Hugo K , Nelson Oliver E 
Published: April 2021

ABSTRACT
The enzyme UPD glucose: flavonoid 3-0-glucosyltransferase (UFGT), involved in anthocyanin biosynthesis, is controlled by at least four genes (Bz, C, R and Vp) in the maize endosperm. Bz is the structural gene for the enzyme. Early in endosperm development, the enzyme is present in an uninduced low level that is independent of C, R and Vp, and dependent solely on Bz. Beginning at about the fourth week of development, C, R and Vp interact with each other to induce high levels of UFGT. The enzyme accumulates thereafter in normal endosperms, reaching its highest level at maturity. The nature of the developmental signal (s) controlled by C, R and Vp is discussed.
ABERRATIONS INDUCED IN CHROMOSOMES OF SOMATIC CELLS OF DROSOPHILA MELANOGASTER IRRADIATED IN C-METAPHASE
Authors: De Marco Antonio , Belloni Maria Pia , Cozzi Renata , Febbo Dario , Ricordy Ruggero 
Published: April 2021

ABSTRACT
Experiments conducted on the X irradiation of neural ganglia of Drosophila melanogaster are described. The ganglia were placed in saline containing colchicine. After two hours; they were irradiated and then samples were fixed at 5,15,25,35 minutes from the beginning of irradiation. The results obtained show that the aberration level increases with time subsequent to fixing. This increase takes place first for chromatid deletions and then for isochromatid deletions and chromatid exchanges. Gaps and subchromatid exchanges do not, on the contrary, show any increase with time. We did not observe a difference in radiosensitivity between the sexes. Some hypotheses are put forth in an attempt to explain these results.
CHIASMA FREQUENCY AND DISTRIBUTION IN A MAIZE FAMILY SEGREGATING FOR K10 AND TRISOMY 10
Authors: Ward E J 
Published: April 2021

ABSTRACT
Chiasma frequency was determined from total chiasma counts, and the distribution of these exchanges was determined by the ratio of proximal to distal chiasmata. No effect of trisomy 10 could be demonstrated. Confirmation was obtained of earlier work showing more proximal and fewer distal chiasmata in K10 plants than in controls. However, diakinesis data failed to confirm the ability of K1O to increase total chiasmata as suggested from metaphase I results.
PARTIAL SELFING AND LINKAGE: THE EFFECT OF A HETEROTIC LOCUS ON A NEUTRAL LOCUS
Authors: Strobeck Curtis 
Published: April 2021

ABSTRACT
Equilibria are determined for the two-locus model in a partially selfing population when one locus is neutral and the other locus is heterotic. At an equilibrium point, the frequency of heterozygotes at the neutral locus is greater than that expected from one-locus theory, even if the heterotic locus is on a different chromosome. Thus, the neutral locus also appears to be heterotic. The magnitude of this effect is determined for several different proportions of selfing and amounts of recombination.
REGULATORY MUTANTS AT THE his1 LOCUS OF YEAST
Authors: Lax Carol , Fogel Seymour , Cramer Carole 
Published: April 2021

ABSTRACT
The hisl gene in Saccharomyces cereuisiae codes for phosphoribosyl transferase, an allosteric enzyme that catalyzes the initial step in histidine biosynthesis. Mutants that specifically alter the feedback regulatory function were isolated by selecting hisl prototrophic revertants that overproduce and excrete histidine. The prototrophs were obtained from diploids homoallelic for his1-7 and heterozygous for the flanking markers thr3 and arg6. Among six independently derived mutant isolates, three distinct levels of histidine excretion were detected. The mutants were shown to be second-site alterations mapping at the his1 locus by recovery of the original auoxtrophic parental alleles. The double mutants, HIS1-7e, are dominant with respect to catalytic function but recessive in regulatory function. When removed from this hisl-7 background, the mutant regulatory site (HIS1-e) still confers prototrophy but not histidine excretion. To yield the excretion phenotype, the primary and altered secondary sites are required in cis array. Differences in histidine excretion levels correlate with resistance to the histidine analogue, triazoalanine.
THE EFFECT OF TEMPERATURE AND PARENTAL AGE ON RECOMBINATION AND NONDISJUNCTION IN CAENORHABDITIS ELEGANS
Authors: Rose A M , Baillie D L 
Published: April 2021

ABSTRACT
The effect of temperature and parental age on recombination frequency in C. elegans was studied between pairs of closely linked markers on linkage groups I and V. In the regions studied, recombination frequency vaned three-fold over the temperature range 13.5° to 26°. Temperature-shift experiments indicated that a temperature-sensitive recombination event occurs approximately 50 oocytes prior to fertilization. Recombination frequency was observed to decrease with maternal age. The greatest decrease was observed in the first 24 hours of egg production. The frequency of male progeny, a measure of X-chromosome nondisjunction was also studied. This frequency increased with elevated temperature and age of the parent.
ANALYSIS OF THE CUT LOCUS OF DROSOPHILA MELANOGASTER
Authors: Johnson T K , Judd B H 
Published: April 2021

ABSTRACT
Mutants of the cut (ct) locus can be divided into two classes: viable and lethal. Most of the viable alleles are characterized by varying degrees of scalloping and notching of the wings. One mutant, kinked femur, exhibits kinking of the femurs and failure of wing expansion, but no other changes in wing structure. In heterozygous combination with the other viable alleles, it exhibits complete complementation, but it fails to complement with lethal ct alleles with respect to its viable phenotype. Similarly, all of the other viable ct alleles express a mutant wing phenotype when heterozygous with lethal ct alleles.—Mapping experiments indicate that the lethal alleles, which comprise the majority of all ct mutations recovered, are confined to a small region at the right end of the locus. That this restriction is real and not an artifact imposed by the limited number of lethal mutations mapped in the locus is supported by an examination of the mutant ctJC20, a presumptive deficiency for the left-most third of the locus. Despite its behavior as a deletion, ctJC20 is viable, though mutant, in combination with the lethal alleles. The restriction of the noncomplementary lethals to a small part of the locus, distinct from the other ct mutants, suggests a polarity that may define a segment that functions only in cis within the complex.—Based on the comparison of the data with the prediction of several models, we suggest that the left portion of the locus, which contains the viable alleles, defines a regulatory region controlling the expression of the locus, while the segment encoding a polypeptide product is at the right end and only it is capable of mutating to a lethal state.
SYNAPTONEMAL COMPLEX AND RECOMBINATION NODULES IN WILD-TYPE DROSOPHILA MELANOGASTER FEMALES
Authors: Carpenter Adelaide T C 
Published: April 2021

ABSTRACT
Electron microscope serial section reconstruction analysis of all zygotene-pachytene nuclei of meiotic cells from three wild-type germaria (a subunit of the ovary containing the early meiotic stages arrayed in temporal developmental sequence) of Drosophila melanogaster females corroborates and extends earlier observations (CARPENTER 1975a) on the nature and sequence of ultrastructural events occurring during the time of meiotic recombination. Emphasis has been placed on (1) the time of appearance and disappearance of the synaptonemal complex (SC) and the changes in its dimensions that accompany a cell's progression through pachytene, and (2) the appearance, disappearance, number and chromosomal locations of recombination nodules (CARPENTER 1975b). For both the SC and the recombination nodule the availability of several developmental series has provided an estimate of the biological variability in the properties of these recombination-associated structures. The much more extensive data presented here substantiate the earlier hypothesis that recombination nodules occur at sites where reciprocal meiotic recombination will occur, has occurred, or is occurring. A second morphological type of recombination nodule is reported; it is suggested that the presence of the latter type of nodule may correlate with sites of gene conversion. The hypothesis that there may be two types of meiotic recombination processes is discussed.
A NEW METHOD TO DISTINGUISH BETWEEN MEIOTIC AND PREMEIOTIC RECOMBINATIONAL EVENTS IN DROSOPHILA MELANOGASTER
Authors: Hiraizumi Yuichiro 
Published: April 2021

ABSTRACT
A new method is proposed to distinguish between meiotic and premeiotic exchange events in Drosophila melanogaster males associated with male recombination activities. The method was applied to data that have accumulated in this laboratory during the past five years, and it was concluded that a large fraction, perhaps the overwhelming majority, of the male recombinants were due to exchange events that took place before meiosis.
POPULATION GENETICS OF DROSOPHILA AMYLASE. I. GENETIC CONTROL OF TISSUE-SPECIFIC EXPRESSION IN D. PSEUDOOBSCURA
Authors: Powell Jeffrey R , Lichtenfels Jenifer M 
Published: April 2021

ABSTRACT
Drosophila pseudoobscura is polymorphic for tissue-specific expression of α-amylase in adult midguts. This enzyme is encoded by a single locus, Amy, on the third chroniosome. In this paper we show: (1) Up to about 12 days post-eclosion, the midgut activity patterns remain stable; after 12 days areas not showing activity previously begin to show activity. ThuS the genes controlling the expression of Amy are temporally acting. (2) Diet affects the quantitative, but not the qualitative, expression of Amy. (3) The expression of Amy in adult midguts is under genetic control. Selection for different frequencies of patterns is possible; realized heritabilities are 0.20 to 0.50. Partial linkage with third chromosome inversions has been demonstrated; the genes or elements controlling Amy expression are not, howevr, confined to the third chromosome. (4) The genetic elements controlling tissue-specific expression of amylase do not coordinately control the expression of five other "digestive-type" enzymes that were studied.—This polymophism appears to be analogous to that studied by ABRAHAM and DOANE (1978) in D. melanogaster, wherein they have mapped regulatory genes.
MATING-TYPE EFFECT ON CIS MUTATIONS LEADING TO CONSTITUTIVITY OF ORNITHINE TRANSAMINASE IN DIPLOID CELLS OF SACCHAROMYCES CEREVISIAE
Authors: Deschamps Jacqueline , Wiame Jean-Marie 
Published: April 2021

ABSTRACT
Cis-acting regulatory mutations have been isolated that affect L-ornithine transaminase (OTAse), an enzyme catalyzing the second step of arginine breakdown in yeast. These mutations lead to constitutive synthesis of OTAse at various levels. Two different types of mutations have been recovered, both of which are tightly linked to the structural gene (cargB) for this enzyme. One type behaves as a classical operator-constitutive mutation similar to the cargB+O-—l mutation previously described (DUBOIS et al. 1978) .—The second type is peculiar in two respects : the higher level of constitutive OTAse synthesis and the expression of constitutivity in diploid cells. These mutations are designated curgB+Oh. They behave as usual operator-constitutive mutations in diploid strains homozygous for mating type (a/a or α/α), but the constitutivity is strongly reduced in a/α diploid cells.