bluuebunny/crossref_metadata_2025_split huggingface dataset:
INTEGRATION EFFICIENCY IN DNA-INDUCED TRANSFORMATION OF PNEUMOCOCCUS. I. A METHOD OF TRANSFORMATION IN SOLID MEDIUM AND ITS USE FOR ISOLATION OF TRANSFORMATION-DEFICIENT AND RECOMBINATION-MODIFIED MUTANTS
Authors: Tiraby Gerard , Claverys Jean-Pierre , Sicard Michel Armand 
Published: January 2021

ABSTRACT
A method of transformation on solid medium especially adapted for pneumococcus has been developed. Under specific conditions, all colonies that are allowed to grow in the presence of transforming DNA for six hours give rise to transformed bacteria. Combined with replica plating this technique has been used to isolate mutants modified with regard to recombination. Most of the mutants found are transformation-defective and show a large diversity in their response to ultraviolet light. Some of these mutants have lost their ability to take up transforming DNA. One shows a reduced yield of transformants for a given quantity of DNA taken up. Mutants that manifest altered behavior with regard to marker efficiencies have also been isolated. One of these exhibits a decrease in the transformation efficiency of only the high efficiency markers and two mutants show a decrease in the transformation efficiency of the low efficiency markers.
THE GENETIC CONTROL AND BIOCHEMICAL MODIFICATION OF CATECHOL OXIDASE IN MAIZE
Authors: Pryor Tony , Schwartz Drew 
Published: January 2021

ABSTRACT
Three isozyme variants of catechol oxidase have been shown to be determined by alleles of a gene, Cx, which has been located on chromosome 10 less than 0.1 recombination units from the endosperm marker du 1.—The extractable form of the enzyme is modified by an endogeneous "modifier" which appears to function as an enzyme substrate. Enzyme and modifier are functionally isolated in intact cells. Modified enzyme has altered kinetics, does not migrate in electrophoresis and most probably results from a "tanning" of the enzyme by reaction products. The content of modifier varies in different lines and is genetically determined by gene(s) independent of Cx. Treatment with maleic hydrazide causes a ten-fold reduction in the modifier content of seedlings, allowing the enzyme to be extracted in an unmodified form which will migrate in electrophoresis.—This system of enzyme and modifier fits the requirements of hypersensitive disease resistance in plants and may provide a test system to investigate the biochemical basis of disease resistance.
THE INHERITANCE OF GOSSYPOL LEVEL IN GOSSYPIUM II: INHERITANCE OF SEED GOSSYPOL IN TWO STRAINS OF CULTIVATED GOSSYPIUM BARBADENSE L
Authors: Lee Joshua 
Published: January 2021

ABSTRACT
Two strains of cultivated Gossypium barbadense L., Sea Island AS-2 and Pima S-4, were used to study the effects of alleles at two loci on the production and/or storage of gossypol in mature embryos. The normal alleles, Gl 2 and Gl 3, are "native" to G. barbadense, whereas the mutant alleles, gl 2 and gl 3, were introduced from Gossypium hirsutum L. through backcrossing. Each strain was grown in three replications per trial, and one, Sea Island AS-2, was grown in three environments. Each experiment consisted of all possible crosses, including reciprocals, of the four true-breeding genotypes, plus parents. Additive effects accounted for more than 90% of the total genetic variance for seed gossypol level in all trials. Epistatic effects, though small, were frequently significant. In G. barbadense Gl 2 and Gl 3 were associated with the production of similar amounts of gossypol, whereas previous trials with cultivated varieties of G. hirsutum showed that Gl 2 was more than twice as expressive as Gl 3. The greater average productivity of seed gossypol in cultivated G. barbadense, as compared with G. hirsutum, was attributed to greater activity at the Gl 3 locus in the former species.
ASSOCIATIONS OF ALLELES OF THE ESTERASE-1 LOCUS WITH GENE ARRANGEMENTS OF THE LEFT ARM OF THE SECOND CHROMOSOME IN DROSOPHILA ROBUSTA
Authors: Prakash Satya , Levitan Max 
Published: January 2021

ABSTRACT
Evidence of strong associations of Est-1 alleles with the 2L, 2L1 and 2L3 gene arrangements of the left arm of the second chromosome in D. robusta is presented. Each gene arrangement is polymorphic for three to four Est-1 alleles. The allele frequencies differ in the 2L3 and 2L arrangements; the allele Est-1.92 is 8% in the 2L3 arrangement (n=203)—this allele is 82% in the 2L arrangement (n=203); the allele Est-11.0 is 66% and 14.8% in the 2L3 and 2L arrangements, respectively. There are no differences in allele frequencies in 2L3 arrangements from any of the widely separated seven different populations; similarly the allele frequencies in the 2L arrangement are alike in all five widely separated populations studied. The allele frequencies in the 2L1 arrangement are intermediate to those observed in the 2L3 and the 2L arrangements and show north-south clinal change. These associations between Est-1 alleles and gene arrangements of the left arm of the second chromosome are due to natural selection favoring different allele frequencies in different gene arrangements, as a result of epistatic interactions between the Est-1 locus and the loci on the gene arrangements. As expected, we observe that the proportion of heterozygotes is greater in the inversion heterokaryotypes than in the homokaryotypes.
FORMATION OF MEGACHROMOSOMES FROM HETEROCHROMATIC BLOCKS OF NICOTIANA TOMENTOSIFORMIS
Authors: Burns J A , Gerstel D U 
Published: January 2021

ABSTRACT
A heterochromatic block (HB) from N. otophora occasionally undergoes great enlargement to form a "megachromosome" in hybrids and hybrid derivatives with N. tabacum. This paper shows that the two large HB's of closely related N. tomentosiformis, and perhaps a smaller one, also have the same capability. The evidence that both large HB's form megachromosomes is twofold. In a segregating backcross population from a parent possessing the two large HB's, all segregants with one block produced megachromosomes at metaphase or large heterochromatic clumps at interphase. Second, those segregants which possessed both heterochromatic blocks produced megachromosomes of two visibly different types. Proliferation to make megachromosomes thus may not be the property of merely one particular segment but a more common property of heterochromatin in a hybrid or otherwise disturbed background.
GENES FOR DWARFNESS IN WHEAT, TRITICUM AESTIVUM L
Authors: Fick G N , Qualset C O 
Published: January 2021

ABSTRACT
The genetic control of plant height was studied in crosses of four spring wheats involving the standard height variety Ramona 50 and short-statured selections Olesen, D6301, and D6899. Data from parent, F1, F2, and F3 populations indicated that four independently segregating loci account for most of the differences among the four varieties. Two major genes of a highly recessive nature condition reduced height in Olesen and the Norin 10 derivative D6301. Olesen also carries a third dwarfing gene which is partially dominant in its effects over genes for tallness. This gene, or a gene that acts in a similar manner, is also present in the standard height variety Ramona 50. Dwarfing in D6899, a derivative of Tom Thumb, is controlled primarily by a single gene with mainly additive effects which is not present in any of the other three varieties.
Genetic components estimated from generation means (parental, F1, F2, F3, and backcross) indicated that additive gene effects were the major component of variation in four of the six crosses, and of similar magnitude to dominance effects in another cross. The primary source of genetic variation in the cross Olesen × D6899 was due to epistasis with both additive × additive and dominance × dominance effects of major importance. The results of the generation mean analyses were consistent with the models for major-gene control of plant height based on segregation patterns.
SELECTION FOR MATING RELUCTANCE IN FEMALES OF A DIPLOID PARTHENOGENETIC STRAIN OF DROSOPHILA MERCATORUM
Authors: Ikeda Hiroshi , Carson Hampton L 
Published: January 2021

ABSTRACT
A diploid parthenogenetic strain of Drosophila mercatorum was outcrossed to produce genetic variance among the impaternate female offspring. Selection experiments were carried out for reluctance of the parthenogenetic females to mate.
After only two cycles of selection, a parthenogenetic strain which is significantly less receptive to males from three different bisexual strains was obtained. It was also found that there is some degree of sexual isolation among the three bisexual strains used. The results support the idea that selection can render a newly produced diploid parthenogenetic strain behaviorally different from its bisexual ancestor. This appears to provide a framework which can explain the natural coexistence of diploid bisexual and diploid parthenogenetic biotypes in some species of insects.
KINETICS OF GENETIC RECOMBINATION IN ESCHERICHIA COLI K-12: COMPETITION BETWEEN GENETIC INTEGRATION AND DEGRADATION
Authors: Ou Jonathan T , Wood Thomas H 
Published: January 2021

ABSTRACT
The effect of shifting zygotes from a rich medium into a poor medium (shift-down) on the frequency of recombination has been examined; our results suggest that protein syntheses other than those required for growth may be involved. Experiments with chloramphenicol support this notion, and further suggest that there is a competition between genetic integration and degradation in the recipient cells. By inhibiting protein synthesis one can shift the competition in favor of either integration or segregation, depending on the physiological state of the zygotes. By calculating the time required for segregation as one generation, we conclude that the recombination chromosome is homozygous at the time of integration.
ACID PHOSPHATASE MUTANTS IN CHLAMYDOMONAS: ISOLATION AND CHARACTERIZATION BY BIOCHEMICAL, ELECTROPHORETIC AND GENETIC ANALYSIS
Authors: Loppes R , Matagne R E 
Published: January 2021

ABSTRACT
In order to isolate acid phosphatase mutants in the green alga Chlamydomonas reinhardi, a staining method for detecting the enzyme activity in colonies has been developed. The occurrence of more than one acid phosphatase brought about some difficulty in the selection of mutants. We have, however, found an original method of selection based on the differential heat sensitivity of the enzymes. After treatment of the wild-type strain with N-methyl-N'-nitro-N-nitrosoguanidine, two types of mutants were recovered, then analyzed by biochemical and electrophoretic methods. In the first class of mutants (P1, P2, P3,…) a heat-stable acid phosphatase bound to cellular debris of the crude extract was missing. The mutant Pa, representing the second class of mutations, was lacking a soluble heat-sensitive enzyme. These mutations were genetically different and exhibited mendelian inheritance.
THE SUPPRESSION OF AD-3B MUTANTS BY SUPERSUPPRESSORS IN NEUROSPORA CRASSA
Authors: Newcombe K D , Griffiths A J F 
Published: January 2021

ABSTRACT
The action of eight suppersuppressors has been tested on 76 ad-3B mutants which were induced by base-pair transition mutagens. Thirteen mutants were found to be suppressible by at least one ssu gene. Most of the suppressible mutants were found to belong to a class in which one would expect to find nonsense mutants (polar complementing or noncomplementing classes, with AT at the mutant site). However, suppression was observed in other classes, including those containing presumed missense mutants. The specificity of the suppressors and the criteria for molecular classification of the mutants are discussed.
MUTATION INDUCTION IN THE MALE RECOMBINATION STRAINS OF DROSOPHILA MELANOGASTER
Authors: Slatko Barton E , Hiraizumi Yuichiro 
Published: January 2021

ABSTRACT
One group of the second chromosome lines isolated from a southern Texas population of Drosophila melanogaster, which has been known to show relatively high frequencies of male recombinations, was found to increase the frequency of sex-linked recessive lethal mutations from a control frequency of 0.18% to 1.63%. The second group, which showed a very much reduced frequency of male recombinations, was found to cause a slight increase to 0.48%, although it was not statistically significant. The first group was also tested for the recessive lethal mutation frequency in the second chromosome; the frequency increased from a control frequency of 0.28% to 2.82%. Mapping of a portion of the sex-linked lethals indicated a distribution along the entire X chromosome, although there was a tendency of clustering towards the tip of the X chromosome. One sex-linked lethal line so far tested was found to be associated with an inversion (approximate breakpoints, 14A–18A). It was suggested that the element causing male recombination might be similar to the hi mutator gene studied earlier by Ives (1950).
THE GENETIC DIVERGENCE OF SUBLINES AS ASSESSED BY HISTOCOMPATIBILITY TESTING
Authors: Silvers Willys K , Gasser David L 
Published: January 2021

ABSTRACT
The degree of genetic divergence which has occurred between a number of inbred strains of mice and between two sublines of inbred rats was assessed by determining the fate of inter-subline skin grafts. Sublines which had been separated for 29 and 42 generations possessed no detectable incompatibility, while three combinations of sublines judged to have been maintained apart for from 123 to 129 generations showed slight degrees of histoincompatibility. One pair of sublines which had been separated for 119 generations demonstrated a marked degree of incompatibility, and an F2 test suggested that mutations had occurred at four or five histocompatibility loci.
LIMITING DISTRIBUTION UNDER ASSORTATIVE MATING
Authors: Ghai G L 
Published: January 2021

ABSTRACT
A multi-locus model for complete positive assortative mating is discussed. For a two-locus model, if the gene frequencies for the two loci are different, as they are likely to be, it is shown that in equilibrium the population is not composed of only two homozygous types, as is usually thought. The limiting distribution will have three homozygous genotypes depending upon the initial gene frequencies. If there are m-loci such that gene frequencies at all loci are different, there will be (m+1) such homozygous genotypes present in the equilibrium population, one in each phenotypic group.
SELECTION IN COMPLEX GENETIC SYSTEMS I. THE SYMMETRIC EQUILIBRIA OF THE THREE-LOCUS SYMMETRIC VIABILITY MODEL
Authors: Feldman Marcus W , Franklin Ian , Thomson Glenys J 
Published: January 2021

ABSTRACT
The symmetric equilibria of the three-locus symmetric viability model are determined and their stability analyzed. For tight linkage there may be four stable equilibria, each characterized by having one pair of complementary chromosomes in high frequencies, with all others low. For looser linkage the only stable symmetric equilibrium is that with complete linkage equilibrium. For intermediate recombination values both types of equilibria may be stable. A new class of equilibria with all pairwise linkage disequilibria zero, but with third order linkage disequilibrium, has been discovered. It may be stable for tight linkage.
A NEW MUTANT CONTROLLING MITOTIC CHROMOSOME DISJUNCTION IN DROSOPHILA MELANOGASTER
Authors: Gelbart William M 
Published: January 2021

ABSTRACT
A new mutant, mit (mitotic loss inducer), is described. The mutant is recessive and maternal in action, producing gynandromorphs and haplo-4 mosaics among the progeny of homozygous mit females. Mosaic loss of maternal or paternal chromosomes can occur. The probabilities of either maternal or paternal X chromosome loss are equal. mit has been mapped to approximately 57 on the standard X chromosome map.—Using gyandromorphs generated by mit, a morphogenetic fate map, placing the origins of 40 cuticular structures on the blastoderm surface, has been constructed. This fate map is consistent with embryological data and with the two other fate maps generated in different ways.
GENETIC ANALYSIS OF DUPLICATE MALATE DEHYDROGENASE LOCI IN THE PINK SALMON, ONCORHYNCHUS GORBUSCHA
Authors: Aspinwall Nevin 
Published: January 2021

ABSTRACT
The results of breeding experiments with the pink salmon, Oncorhynchus gorbuscha, indicate that s-MDH-A and s-MDH-B subunits are each encoded by duplicate loci. Limited evidence suggests also that the two loci encoding for the s-MDH-A subunit are each polymorphic and linked or pseudolinked.
AN ELECTROPHORETICALLY SILENT POLYMORPHISM FOR THE BETA CHAINS OF RABBIT HEMOGLOBIN AND ASSOCIATED POLYRIBOSOME PATTERNS
Authors: Garrick Michael D , Bricker J , Garrick Laura M 
Published: January 2021

ABSTRACT
The β chain of rabbit (Oryctolagus caniculus) hemoglobin has previously been reported to contain a single residue of isoleucine at β112. We have detected other rabbits with either zero isoleucyl residues or half a residue per β chain. This character is polymorphic and inherited as a simple mendelian autosomal codominant.—Normally the modal number of ribosomes per polyribosome is 4 to 6 in reticulocyte lysates; but incubation of rabbit reticulocytes prior to lysis with L-o-methylthreonine (OMT), an isostere of isoleucine, leads to a bimodal distribution in lysates with 2–3 and 8–12 ribosomes as modes. This alteration has been attributed to ribosomal traffic jams caused by starvation for ile-tRNA at mRNA codons corresponding to the locations of isoleucyl residues at positions α10, α17, α55 and β112. We have confirmed this interpretation by incubating OMT with reticulocytes from rabbits with integral, half integral and nil values for isoleucyl residues per β chain to show that formation of the larger clusters of polyribosomes requires that β112 = ile.
GENETIC ANALYSIS OF AN ESCHERICHIA COLI MUTANT WITH A LESION IN STABLE RNA TURNOVER
Authors: Ohnishi Yoshinari 
Published: January 2021

ABSTRACT
A mutant that rapidly degrades more than 80% of its rRNA and tRNA under defined conditions was genetically analyzed. Two genes, srnA and srnB, are separately located, and the mutated alleles of both are required for degradation of stable RNA in cultures treated with rifampicin at 42°. srnA is closely linked to tsx by matings and transduction tests; by P1 transduction, the gene order is lac (9 min) proC (9.55 min) tsx (9.8 min) srnA (about 10 min) purE (12 min) rnsA (14.4 min). srnB is not yet completely mapped, but is outside the lac-rnsA region, probably in the region between 75 and 90 min.—The product of the rnsA gene, RNase I, is a potent endonuclease of E. coli, and the only one known that can attack ribosomes and tRNA. However, not only are the srn lesions genetically separate from rnsA, but also, derivatives of an srn strain were prepared lacking RNase I, and they retain the Srn- phenotype. Thus, no correlation of rapid RNA turnover and RNase I activity has been found.
MITOCHONDRIAL GENETICS. VI THE PETITE MUTATION IN SACCHAROMYCES CEREVISIAE: INTERRELATIONS BETWEEN THE LOSS OF THE ρ+ FACTOR AND THE LOSS OF THE DRUG RESISTANCE MITOCHONDRIAL GENETIC MARKERS
Authors: Deutsch J , Dujon B , Netter P , Petrochilo E , Slonimski P P , Bolotin-Fukuhara M , Coen D 
Published: January 2021

ABSTRACT
The survival of the ρ+ factor and of DrugR mitochondrial genetic markers after exposure to ethidium bromide has been studied. A technique allowing the determination of DrugR genetic markers among a great number of both grande and petite colonies has been developed. The results have been analyzed by the target theory. The survival of the ρ+ factor is always less than the survival of any DrugR genetic marker. The survivals of CR and ER are similar to each other, while that of OR is greater than that of the other two DrugR markers. All possible combinations of DrugR markers have been found among the ρ- petite cells induced, while the only type found among the grande colonies is the preexisting one. The loss of the CR and ER genetic markers was found to be the most frequently concomitant, while the correlation between the loss of the OR marker and the other two DrugR markers is less strong. Similar results have been obtained after U.V. irradiation. Interpretations concerning the structure of the yeast mitochondrial genome are given and hypotheses on the mechanism of petite mutation discussed.
PREFERENTIAL ASCUS DISCHARGE DURING CROSS MATURATION IN SORDARIA BREVICOLLIS
Authors: MacDonald D J , Bond D J 
Published: January 2021

ABSTRACT
Crosses involving spore color mutants of Sordaria brevicollis all showed a decline in the frequency of second division asymmetric asci (2:2:2:2's) as the cross matured. This decline was due to the preferential maturation and/or discharge of these asci. The proportion of spindle overlap and recombinational asci within the group did not change as shown by ascus dissection. The preferential discharge was also found to occur in two-point crosses where the asci did not contain wild-type spores.
MUTATIONS AFFECTING SEXUAL CONJUGATION AND RELATED PROCESSES IN SACCHAROMYCES CEREVISIAE. II. GENETIC ANALYSIS OF NONMATING MUTANTS
Authors: Mackay Vivian , Manney Thomas R 
Published: January 2021

ABSTRACT
Rare diploids formed by sterile mutants have been studied by tetrad analysis. Sixteen classes of mutants representing at least five distinct genetic loci have been defined. One group of mutations, isolated only in α, maps at the mating-type locus, while none of the others shows any linkage to mating type. Some of the mutations are nonspecific for mating type, while others act only on a or α. In addition, mutations were found that prevent sporulation when heterozygous in diploids. These appear to be mutations of the mating-type alleles.
MORTALITY IN THE CHILDREN OF ATOMIC BOMB SURVIVORS AND CONTROLS
Authors: Neel James V , Kato Hiroo , Schull William J 
Published: January 2021

ABSTRACT
A continuing study of mortality rates among children born to survivors of the atomic bombings and a suitable group of controls has been updated; the average interval between birth and verification of death or survival is 17 years. The mortality experience is now based on 18,946 children liveborn to parents one or both of whom were proximally exposed, receiving jointly an estimated dose of 117 rem; 16,516 children born to distally exposed parents receiving essentially no radiation; and 17,263 children born to parents not in Hiroshima or Nagasaki at the time of the bombings. No clearly significant effect of parental exposure on child's survival can be demonstrated either by a contingency χ2 type of analysis or regression analysis. On the basis of the regression data, the minimal gametic doubling dose of radiation of this type for mutations resulting in death during (on the average) the first 17 years of life among liveborn infants conceived 0–13 years after parental exposure is estimated at 46 rem for fathers and 125 rem for mothers. On the basis of experimental data, the gametic doubling dose for chronic, low-level radiation would be expected to be three to four times this value for males and as much as 1000 rem for females.