bluuebunny/crossref_metadata_2025_split huggingface dataset:
INTERPRETATION OF DATA OBTAINED WITH RECOMBINATION-DEFECTIVE MEIOTIC MUTANTS
Authors: Valentin Jack , Ståhl Gunnar 
Published: April 2021

ABSTRACT
According to probability laws, additive interaction between factors influencing recombination frequency suggests that the factors affect the same event. This analysis, applied to Carpenter and Sandler's (1974) data, permits separation of different sequential events during establishment of preconditions for exchange. The validity of another mathematical model for meiotic mutant characterization, suggested by those authors, is discussed.
SELECTION FOR ANNUAL GROWTH CURVES IN NICOTIANA TABACUM L
Authors: Namkoong G , Matzinger D F 
Published: April 2021

ABSTRACT
The cumulative growth of a plant is the result of interrelated processes, and response to selection for changes in the annual growth curve requires many physiological adjustments. Selection to modify the entire annual growth curve may therefore not be as effective as linear models may predict. Periodic growth of a population of Nicotiana tabacum L. was estimated to have heritabilities increasing from 7% up to 31% for successive heights, with positive genetic and phenotypic correlations among all periods. Two selection experiments on this population indicate the difficulties of using simple index selection to raise the entire growth curve. A selection index of eight periodic heights resulted in a gain in all periods for the first cycle of selection but mixed losses and gains in subsequent cycles for a small net gain after four cycles of selection. A selection index of three parameters of a nonlinear height growth function resulted in a consistent change in the growth curves over the four cycles of selection but a net loss in early growth and a large net gain in late-season growth.
RIBOSOMAL DNA IN A NUCLEAR SATELLITE OF TOMATO
Authors: Chilton Mary-Dell 
Published: April 2021

ABSTRACT
A satellite DNA of buoyant density 1.704 constitutes approximately 5%–6% of nuclear DNA isolated from cherry tomato leaves. Isolated satellite DNA exhibits a multi-component melting profile. Kinetic complexity measurements indicate that 37% of the satellite consists of repeating units of 105 daltons, and 48% of it consists of repeating units of 5.5 × 106 daltons. The latter component is identified as DNA coding for ribosomal RNA on the basis of its buoyant density, kinetic complexity, and abundance in nuclear DNA, 3.2% as determined by saturation hybridization measurements. Saturation studies show that the more rapidly reassociating component of the satellite does not code for 5S RNA. The question of genetic linkage between satellite components is not resolved by this study.
MAPPING AND GENE CONVERSION STUDIES WITH THE STRUCTURAL GENE FOR ISO-1-CYTOCHROME C IN YEAST
Authors: Lawrence Christopher W , Sherman Fred , Jackson Mary , Gilmore Richard A 
Published: April 2021

ABSTRACT
We have investigated the order of the four genes cyc1, rad7, SUP4, and cdc8 which form a tightly linked cluster on the right arm of chromosome X in the yeast Saccharomyces cerevisiae. Crossing over and coconversion data from tetrad analysis established the gene order to be centromere–cyc1–rad7–SUP4. Also cdc8 appeared to be distal to SUP4 on the basis of crossovers that were associated with conversion of SUP4. The frequencies of recombination and the occurrence of coconversions suggest that these four genes are contiguous or at least nearly so. Gene-conversion frequencies for several cyc1 alleles were studied, including cyc1–1, a deletion of the whole gene that extends into the rad7 locus. The cyc1–1 deletion was found to be capable of conversion, though at a frequency some fivefold less than the other alleles studied, and both 3:1 and 1:3 events were detected. In general 1:3 and 3:1 conversion events were equally frequent at all loci studied, and approximately 50% of conversions were accompanied by reciprocal recombination for flanking markers. The orientation of the cyc1 gene could not be clearly deduced from the behavior of the distal marker SUP4 in wild-type recombinants that arose from diploids heteroallelic for cyc1 mutations.
MULTILOCUS BEHAVIOR IN RANDOM ENVIRONMENTS I. RANDOM LEVENE MODELS
Authors: Gillespie John , Langley Charles 
Published: April 2021

ABSTRACT
In this paper the consequences of natural selection acting on several loci simultaneously in a spatially fluctuating environment are described. The fitnesses of the genotypes are assumed to be additive both within and between loci. The environment is assumed to be made up of a very large (effectively infinite) number of patches in which fitnesses are assigned at random. The resulting deterministic model is called a Random Levene Model and its properties are approximated by a system of differential equations. The main equilibrium properties are that (1) the linkage disequilibrium is zero and (2) the correlations in fitnesses between alleles at different loci are the principle determinants of the dynamic inter-locus interactions. Although there is no epistasis as conventionally defined, the equilibrium state at the two loci are highly interdependent, the governing principle being that two alleles at different loci whose fitness are negatively correlated across environments have a higher overall fitness due to the reduction in their variance in fitness through the negative correlation. When a large number of loci are considered, they naturally fall into correlation groupings which lead to an enhanced likelihood for polymorphism over that predicted by single-locus theory.
LINKAGE ANALYSIS OF THE MULTILOCUS GLUCOSEPHOSPHATE ISOMERASE ISOZYME SYSTEM IN SUNFISH (CENTRARCHIDAE, TELEOSTII)
Authors: Whitt Gregory S , Childers William F , Shaklee James B , Matsumoto Janet 
Published: April 2021

ABSTRACT
The purpose of the present investigation is to determine whether the two duplicated glucosephosphate isomerase (EC 5.3.1.9) loci Gpi-A and Gpi-B reside on the same chromosome in teleostean fishes. Interspecific sunfish hybrids were employed for the cross because of the different species-specific electrophoretic mobilities of the allelic isozymes at each GPI locus and because of their genomic compatibility. F1 sunfish hybrids, formed from a male warmouth (Lepomis gulosus) × female green sunfish (L. cyanellus) cross, were mated to form the F2 generation. The number of each of the nine different isozyme phenotypes, revealed by starch gel electrophoresis, was determined using 256 F2 individuals. The high frequency of recombinant phenotypes in the F2 generation indicated that the two GPI loci are not linked. An excess of F2 individuals heterozygous at both loci was observed and is interpreted as being caused by heterosis. The absence of linkage for the homologous loci encoding GPI subunits and for other multilocus isozyme systems is consistent with the postulate that the genomes of present-day vertebrates arose through one or more polyploidization events early in vertebrate evolution.
EVOLUTION OF EXPERIMENTAL "MUTATOR" POPULATIONS OF DROSOPHILA MELANOGASTER
Authors: Benado Moritz B , Ayala Francisco J , Green Melvin M 
Published: April 2021

ABSTRACT
The theory of evolution predicts that the rate of adaptation of a population is a function of the amount of genetic variation present in the population. This has been experimentally demonstrated in Drosophila populations in which genetic variability was increased either by mass hybridization of two gene pools, or by X-irradiation.—Mutator genes increase the spontaneous mutation rates of their carriers. We have now studied the effects of a third-chromosome mutator gene, mt, on the rate of adaptation of laboratory populations. Initially, experimental and control populations had similar genetic constitutions except for the presence or absence of the mt gene. The populations were maintained for 20–25 generations by "serial transfer" under conditions of very intense selection.—The number of flies produced per unit time remained constant throughout the experiment in the experimental as well as in the control populations. However, in the mutator-carrying populations the average longevity of the flies (and consequently the average population size) gradually decreased. Under the experimental conditions natural selection is unable to counteract completely the increased input of deleterious mutations due to the mt gene.
A CLASS OF GENES AFFECTING B FACTOR-REGULATED DEVELOPMENT IN SCHIZOPHYLLUM COMMUNE
Authors: Dubovoy Celia 
Published: April 2021

ABSTRACT
Twelve mutations affecting nuclear migration, a major developmental phase in Schizophyllum commune, display a complex pattern of complementation and recombination. They are expressed only when a genetic factor controlling this phase of development, the B incompatibility factor, is operative. All twelve mutations are linked to the B factor, nine in a cluster and three in distinct loci outside the cluster. A linear map cannot be constructed from the frequency of recombination. Complementation maps are not linear. There is little correlation between the complementation groups and the groups based on recombination. Many pairs of mutations that do not complement recombine with frequencies of 1.1% to 26.9%. The genes represented by the twelve mutations are located in a linked group of about 18 known genes involved in the specific phase of development controlled by the B factor.
AVIAN RIBOFLAVINURIA IX. QUALITATIVE ACTION OF A MUTANT GENE IN CHICKEN ON RIBOFLAVIN-BINDING PROTEIN SYNTHESIS
Authors: Hammer C H , Buss E G , Clagett C O 
Published: April 2021

ABSTRACT
Laying chickens normally produce a riboflavin-binding protein (RBP) essential for the transfer of vitamin B2 to the egg. A mutant line of chickens (rdrd) is incapable of synthesizing functional RBP. The rdrd laying hens contain a component in the liver and the magnum of the oviduct which crossreacts with rabbit antiserum specific for RBP. No crossreacting material (CRM) was observed in eggs or blood of rdrd hens. CRM is absent in extracts of livers of rdrd males, but it can be induced in roosters of this genotype by estradiol. CRM appears to be less immunogenic on a weight basis than RBP, and it carries less net negative charge. No measurable riboflavin-binding capacity was found for newly isolated or degraded CRM.
COMPARATIVE AUTOSOMAL LINKAGE IN MAMMALS: GENETICS OF ESTERASES IN MUS MUSCULUS AND RATTUS NORVEGICUS
Authors: Womack James E , Sharp Mark 
Published: April 2021

ABSTRACT
Recombination between Esterase-4 and Esterase-2 in the rat was not observed in 278 backcross offspring. Es-4 is thus included within the "esterase cluster" in Linkage group V. A new map of this region was constructed and the relationship of the four esterase loci was found to be: Es-4-(9.6 ± 1.6 cM)-Es-2, Es-4-(1.5 ± 0.7 cM)-Es-3. Homology of this region with a region of Linkage Group XVIII (Chromosome 8) of the mouse was proposed on the basis of tissue distribution, subcellular localization and response of enzymes to inhibitors. Specifically, rat Es-1 was suggested as the homolog of mouse Es-2, rat Es-2as the homolog of mouse Es-1, and rat Es-4 as the homolog of mouse Es-6. An autosomal segment comprising at least 15 cM of the rat and mouse genomes appears to have remained relatively intact with respect to genetic content during rodent speciation. In addition, a new polymorphism for mouse esterase was described. The locus was designated Esterase-10 (Es-10) and proposed as the mouse homolog of human Esterase D. Linkage of Es-10 with nucleoside phosphorylase-1 (Np-1) on Chromosome 14 was established.
GALACTOKINASE MUTANTS OF CHINESE HAMSTER SOMATIC CELLS RESISTANT TO 2-DEOXYGALACTOSE
Authors: Thirion Jean-Paul , Banville Denis , Noel Henri 
Published: April 2021

ABSTRACT
The growth of Chinese hamster somatic cells was inhibited by 0.2 mg/cc of 2-deoxygalactose. Mutants partially or fully resistant to 2-deoxygalactose were isolated in a single-step or two-step selection. Some of them did not grow as well as the wild type; one of them which lacked galactokinase (EC.2.7.1.6) activity did not grow at all in galactose medium. The galactokinase kinetic properties (Vmax & Kmax) of the other mutants and of the wild type were different. Therefore resistance resulted either from the possible absence of galactokinase synthesis or from a structural mutation, possibly a missence mutation, in the galactokinase gene.—A simple diagnostic test for juvenile cataract is proposed.
EFFECT OF GENES CONTROLLING RADIATION SENSITIVITY ON CHEMICALLY INDUCED MUTATIONS IN SACCHAROMYCES CEREVISIAE
Authors: Prakash Louise 
Published: April 2021

ABSTRACT
The effect of 16 different genes (rad) conferring radiation sensitivity on chemically induced reversion in the yeast Saccharomyces cerevisiae was determined. The site of reversion used was a well-defined chain initiation mutant mapping in the structural gene coding for iso-1-cytochrome c. High doses of EMS and HNO2 resulted in decreased reversion of cyc1-131 in rad6, rad9 and rad15 strains compared to the normal RAD+ strains. In addition, rad52 greatly decreased EMS reversion of cyc1-131 but had not effect on HNO2-induced reversion; rad18, on the other hand, increased HNO2-induced reversion but did not alter EMS-induced reversion. When NQO was used as the mutagen, every rad gene tested, except for rad14, had an effect on reversion; rad6, rad9, rad15, rad17, rad18, rad22, rev1, rev2 and rev3 lowered NQO reversion while rad1, rad2, rad3, rad4, rad10, rad12 and rad16 increased it compared to the RAD+ strain. The effect of rad genes on chemical mutagenesis is discussed in terms of their effect on UV mutagenesis. It is concluded that although the nature of the repair pathways may differ for UV- and chemically-induced mutations in yeast, a functional repair system is required for the induction of mutation by the chemical agents NQO, EMS and HNO2.
CHLOROPLAST GENETICS OF CHLAMYDOMONAS. III. CLOSING THE CIRCLE
Authors: Singer Burt , Sager Ruth , Ramanis Zenta 
Published: April 2021

ABSTRACT
A novel mapping procedure is presented for organelle genes or any other genetic system exhibiting a measurable frequency of exchanges occurring at a constant rate over a measurable time interval. For a set of markers in a multiply-marked cross, the exchange rates measure relative map distances from a centromere-like attachment point.
With this method, we present mapping data and a linear map of genes in the chlcroplast genome of Chlamydomonas. The data are plotted as log (percent remaining heterozygotes) against time and map distances are taken as proportional to slope.
A statistical method which is an adaptation of jackknife methodology to a regression problem was developed to estimate slope values. A single line is fitted to pooled data for each marker from several crosses, and then lines are re-fit to a series of pooled data sets in each of which the observations from a single cross have been omitted. From these data sets a final summary slope is computed as well as a statement of its variability. The relative positions of new markers present in single crosses can then be estimated utilizing data from many crosses.
The method does not distinguish between one-armed and two-armed linear or circular maps. However, evaluation of this map in conjunction with cosegregation frequency data (Sager and Ramanis 1976b) provides unambiguous evidence of the genetic circularity of the Chlamydomonas chloroplast genome.
GENETIC CHANGE IN MUTATIONS AT THE T/t-LOCUS IN THE MOUSE
Authors: Bennett Dorothea , Dunn L C , Artzt Karen 
Published: April 2021

ABSTRACT
Recessive lethal or semilethal alleles at the T/t locus in the mouse generate new t-variants, with characteristics different from the parent allele at a rate of about 10-3. Almost invariably the variant chromosome carries marker genes derived from the opposite parental chromosome. New t-mutations obtained in this way are sometimes recessive lethals that are indistinguishable from those in already known complementation groups. Most derived t-mutations are viable, however. This paper summarizes data on the rate and types of variants produced by members of each of the six lethal complementation groups, and by semilethal alleles. It appears that particular complementation groups preferentially generate certain types of variants, and that in general, the pattern of variant production runs "uphill," that is, to less abnormal states. The data are compatible with the hypothesis that t-mutations represent some extent of altered chromosome and that variants are produced by loss of abnormal material.
GROWTH RATE, BODY COMPOSITION, CELLULAR GROWTH AND ENZYME ACTIVITIES IN LINES OF TRIBOLIUM CASTANEUM SELECTED FOR 21-DAY PUPA WEIGHT
Authors: Medrano Juan F , Gall G A E 
Published: April 2021

ABSTRACT
Growth rate, body composition, cell number, cell size, and the activity of four dehydrogenase enzymes were studied from 10 to 25 days of age in one control (1C) and three lines (3, 9, 10) of Tribolium castaneumthat had been subjected to long term selection for large 21-day pupae weight.—Selected lines were two- to three-fold larger in size than the control line throughout development. No major differences in percent of protein were detected among the lines but at any particular age, the selected lines were found to have a higher fat content than the control line. The differences in fat content were closely correlated with development such that all the lines reached very similar levels of percent of fat just prior to pupation. Water content showed an inverse relation to percent of fat.—Selection was observed to have caused major changes in the cellular response to growth. The selected lines had an average of from 17% to 48% larger cells (measured as protein/DNA) and were found to have from 37 to 62% more cells (measured as total DNA) than the control line at all ages from 10 to 19 days of age. In addition, the selected lines had a higher RNA content at all ages studied and higher RNA:DNA ratios at the young ages. In contrast the enzyme activities of ICDH and LDH were 60% lower. The results are interpreted as indicating that a more efficient metabolic machinery had evolved in the rapidly growing selected lines.
HIGH RATES OF OCCURRENCE OF SPONTANEOUS CHROMOSOME ABERRATIONS IN DROSOPHILA MELANOGASTER
Authors: Yamaguchi Osamu , Cardellino Ricardo A , Mukai Terumi 
Published: April 2021

ABSTRACT
Spontaneous mutations were accumulated for 40 generations in 140 unrelated second chromosomes with the standard gene arrangement. These were extracted from the same population by using the marked inversion technique, and the following findings were obtained: (1) In 42 out of the 140 chromosome lines, chromosome aberrations were detected by examining the salivary gland chromosomes: 40 paracentric and 15 pericentric inversions, 2 reciprocal translocations between the second and the third chromosomes, and 6 transpositions. (2) In 63 out of the 90 originally lethal-free lines, recessive lethal mutations occurred. (3) There were only 3 lines that acquired chromosome aberrations (inversions) with no lethal effects in the homozygous condition. (4) In a comparison of these results with those of the (CH), (PQ), and (RT) chromosomes in which no chromosome aberrations occurred after accumulating mutations for 22058 chromosome·generations (Yamaguchi and Mukai 1974), it was concluded that some of these 140 chromosomes carried a kind of mutator. (5) The frequency of mutator-carrying chromosome lines was estimated to be 0.66 on the basis of the distribution of the break-points on the chromosome lines and the frequency of lines that acquired neither recessive lethal mutations nor chromosome aberrations. Thus, the average number of breaks per mutator-carrying chromosome was estimated to be about 0.19/generation.
On the basis of these estimates, the nature of the mutator factor was discussed.
INDUCIBLE MONOOXYGENASE ACTIVITIES AND 3-METHYLCHOLANTHRENE-INITIATED TUMORIGENESIS IN MOUSE RECOMBINANT INBRED SUBLINES
Authors: Atlas Steven A , Taylor Benjamin A , Diwan Bhalchandra A , Nebert Daniel W 
Published: April 2021

ABSTRACT
The induction of a certain group of hepatic monooxygenase activities by polycyclic aromatic compounds is regulated by the same locus or gene cluster controlling the formation of cytochrome P1–450 (P–448) in mice. Certain inbred strains of mice are "responsive" (Ahb) to such induction, whereas others are "nonresponsive" (Ahd). A pair of closely related sublines that differ with respect to the Ahlocus (for aromatic hydrocarbon responsiveness) were used to identify or confirm the pleiotropic effects of this gene. The lines were derived by sibling-mating without selection from (C57L/J × AKR/J)F2 mice; the two sublines were separated at the F12 generation. Ten microsomal monooxygenase activities and one cytosol enzyme activity known to be associated with the Ah locus were similarly associated with cytochrome P1–450 formation in these recombinant inbred sublines as well. Nine additional hepatic monooxygenase activities studied were found not to be associated with the Ah locus; certain of these activities were increased slightly, following treatment of nonresponsive as well as responsive mice with polycyclic aromatic compounds. The Ahb-containing subline was highly susceptible to 3-methylcholanthrene-induced subcutaneous sarcomas, whereas the Ah-d-containing subline was relatively resistant. These results emphasize the potential importance of this particular enzyme for the study of coordinated regulation in mammals.
GENE EXPRESSION IN ALLOPLOIDS: GENETIC CONTROL OF LIPOPUROTHIONINS IN WHEAT
Authors: De Caleya R Fernandez , Hernandez-Lucas C , Carbonero Pilar , Garcia-Olmedo F 
Published: April 2021

ABSTRACT
Lipopurothionins are complexes of basic polypeptides and polar lipids found in petroleum ether extracts of wheat endosperm. Location of the structural genes for the protein moiety and of genes probably controlling the lipid moiety has been achieved by analysis of compensated nulli-tetrasomic and ditelosomic lines of Triticum aestivum L. cv. Chinese Spring, as well as of other genetic stocks. There are two electrophoretic variants of the apoprotein designated α and β purothionins. Structural genes for α purothionins are located in the long arm of chromosomes 1B and 1D, and for the β variant in the long arm of 1A. These genes have been tentatively designated Pur-A1, Pur-B1, and Pur-D1. The aminoacid composition of purified α and β purothionins from Triticum aestivum (genomes AABBDD) and T. durum (AABB), and of β purothionin from T. monococcum (AA) is also consistent with this conclusion and suggests that the α purothionin encoded by gene Pur-B1 probably differs from that encoded by gene Pur-D1 in at least three positions of the aminoacid sequence. A gene (or genes) located in the short arm of chromosome 5D markedly affects the level of lipopurothionin but does not affect apoprotein synthesis. It is concluded that they control the lipid moiety which is required for solubility in petroleum ether.
Q- AND C-BAND CHROMOSOME MARKERS IN INBRED STRAINS OF MUS MUSCULUS
Authors: Miller D A , Tantravahi R , Dev V G , Miller O J 
Published: April 2021

ABSTRACT
Differences in the number of chromosomes with secondary constrictions and in the size of the C-band region on certain chromosomes have been observed among the following inbred strains of Mus musculus: C57BL/10J, C57BR/cdJ, DBA/1J, CBA/J, BALB/cJ, and AKR. These differences are useful as indicators of the location of rRNA genes and as normal chromosome markers. The size of each C-band region appears to remain constant over many generations. Only one probable change in the size of a C-band region was found.