bluuebunny/crossref_metadata_2025_split huggingface dataset:
LAMBDA CIN-1, A NEW MUTATION WHICH ENHANCES LYSOGENIZATION BY BACTERIOPHAGE LAMBDA, AND THE GENETIC STRUCTURE OF THE LAMBDA CY REGION
Authors: Wulff Daniel L 
Published: April 2021

ABSTRACT
Seven lambda cy mutants have been mapped within a small region located approximately halfway between the rightward boundary of the imm434 region and the lambda cII gene. The seven mutants lie at four sites separated by a total distance of about 12 nucleotide pairs, as estimated from recombination frequencies. Six of the seven mutants lie on the right side of the cy fine structure map, spanning a total distance of about 3-5 nucleotide pairs. Lying approximately 11-21 nucleotide pairs to the left of the leftmost cy mutant is a newly described mutation called cin-1, for c independent. The cin-1 mutation allows some lysogenization when coupled with any cy, cII or cIII mutant, but not when coupled with a defective cI gene. The cin-1 mutation, like cy mutants, has a cis-dominant action upon the cI gene in mixed infections. The observation that λimm434 cin-1 cy2001 lysogenizes efficiently, but not λimm434 cin-1 cy2001 cII68 nor any other λimm434 cin-1 cy derivative, is interpreted to mean that all of the cy mutants on the right side of the cy fine structure map inactivate a binding site for cII/cIII function, but that cy2001, the single mutant on the left side of the cyfine structure map, does not inactivate that binding site.
GENETICS OF MURINE LIVER AND KIDNEY ARYLSULFATASE B
Authors: Daniel William L 
Published: April 2021

ABSTRACT
Mice from 12 inbred strains were surveyed for variation of kidney and liver arylsulfatase levels. Kidney variation was due to differences in the activity of arylsulfatase B. Twofold higher activities of arylsulfatase B in SWR/J kidney compared to A/HeJ kidney were determined by an autosomal gene which may be identical to the structural gene for arylsulfatase B since the SWR/J enzyme was more heat-stable than the A/HeJ enzyme. C57BL/6J mice possessed twofold higher liver arylsulfatase levels than did A/HeJ mice. The major portion of this variation could be attributed to differences in arylsulfatase B, and appeared to be inherited in autosomal fashion. Although some evidence supports the existence of a major locus influencing liver arylsulfatase activity, this must be substantiated by further studies. Whatever the nature of the genetic factors involved, they do not appear to involve structural genes since no differences were discernible between the enzymes of the two strains relevant to Km, heat stability, electrophoretic mobility, pH optimum, activation energy, or response to several inhibitors. Furthermore, the rank ordering of strains on the basis of kidney arylsulfatase activity differed markedly from that which pertained to liver activity. Kidney arylsulfatase levels, but not brain or liver arylsulfatase activities, appear subject to androgenic influences.
MORE ON NEI AND ROYCHOUDHURY'S SAMPLING VARIANCES OF HETEROZYGOSITY AND GENETIC DISTANCE
Authors: Mitra S 
Published: April 2021

ABSTRACT
The inequality relationship between the expected values of (jx-g)2 and (ĝ-g)2, where jx is a biased and ĝ is an unbiased estimate of population homozygosity g, were examined earlier by Nei and Roychoudhury (1974) and later by Mitra (1975). The improvement in the inequality still left much to be desired. In this paper a lower boundary of g has been obtained which may be regarded as ultimate for ensuring a smaller expected value of (jx-g)2 than the corresponding value of (ĝ-g)2.
ON RECOMBINATION BETWEEN CLOSE AND DISTANT MARKERS IN PHAGE LAMBDA
Authors: Stahl Franklin W , Stahl Mary M 
Published: April 2021

ABSTRACT
The contribution of parental DNA to progeny phages genetically recombinant for close markers, distant markers, or both simultaneously was studied in biparental and triparental replication-blocked crosses. The data are compatible with the previously proposed view that heterozygous overlaps at the sites of crossing over are sometimes about as long as the lambda chromosome. However, about half of the close marker recombinants have enjoyed triparental interactions, attenuating that conclusion and obscuring predictions of the long overlap model.
PHENOTYPIC DIVERSITY AMONG ALLELES AT THE PER-1 LOCUS OF NEUROSPORA CRASSA
Authors: Howe H Branch , Johnson T E 
Published: April 2021

ABSTRACT
Comparison of 11 perithecial color mutants suggested that all were alleles at the per-1 locus but nonetheless separable into two groups because of phenotypic differences. Three of the mutant strains produced orange perithecia and black ascospores, and eight produced paler, yellow perithecia and white ascospores. Perithecial phenotype was dependent upon the genotype of the protoperithecial parent; ascospore phenotype, upon the genotype of the individual ascospore. No evidence was found that the white ascospores were due to chromosomal rearrangements. No separation of the perithecial and ascospore phenotypes by recombination was observed in a cross between one of the mutants and a per-1 + strain. However, apparent low levels of recombination in crosses between some of the mutants indicated possible genetic complexity at the per-1 locus. The phase specificity of the per-1 mutations and the possible nature and mode of expression of the orange and yellow perithecial pigments are discussed.
MITOCHONDRIAL GENETICS. XII. AN OLIGOMYCIN-RESISTANT MUTANT LOCALIZED AT A NEW MITOCHONDRIAL LOCUS IN SACCHAROMYCES CEREVISIAE
Authors: Clavilier Léa 
Published: April 2021

ABSTRACT
Three antibiotic-resistance mutations were isolated from strain FL496–2B: two are independent Mendelian genes, one conferring both oligomycin and venturicidin resistance (oliR 496) and the other conferring cycloheximide resistance (cyhR 496). The third is a mitochondrial mutation, OR 9, and confers a low level of oligomycin resistance to cells (in vivo) but not to the extracted mitochondrial ATPase (in vitro). This mutation is located on the mitochondrial DNA at a new locus [OLI4] linked to [OLI2] and independent from [OLI1] and [OLI3] and from the other mitochondrial loci.
All three mutations (OR 9, oliR 496, cyhR 496) were found without any selection, in the same prototrophic haploid strain, which contained unknown resistances to antibiotics.
Some physiological, genetical and biochemical properties of the mitochondrial mutation are described.
CHARACTERIZATION OF T4 MUTANTS THAT PARTIALLY SUPPRESS THE INABILITY OF T4rII TO GROW IN LAMBDA LYSOGENS
Authors: Homyk Theodore , Rodriguez Angel , Weil Jon 
Published: April 2021

ABSTRACT
In the course of isolating viable T4 deletions that affect plaque morphology (Homyk and Weil 1974), two closely linked point mutants, sip1 and sip2, were obtained. They map between genes t and 52, cause a reduction in plaque size and burst size, and partially suppress the lethality of rII mutants for growth in lambda lysogens. These characteristics demonstrate that sip1 and sip2 are similar to mutants previously reported by Freedman and Brenner (1972). In addition, D. Hall (personal communication) has shown that sip1 and sip2 are similar to the mutant farP85, which affects the regulation of a number of early genes (Chace and Hall 1975).—Sip suppression of rII mutants can be demonstrated in one-step growth experiments, even when both rII genes are completely deleted. This indicates that sip mutants do not simply reduce the level of rII gene products required for growth in a lambda lysogen. Instead, they alter the growth cycle so as to partially circumvent the need for any rII products.—Mutations at two other sites, designated L1 and L2, reverse the poor phage growth caused by sip and, in the one case tested, reverse the rII-suppressing ability of sip.
GENETICS OF ACETYLCHOLINESTERASE IN DROSOPHILA MELANOGASTER
Authors: Hall Jeffrey C , Kankel Douglas R 
Published: April 2021

ABSTRACT
Genes in Drosophila melanogaster that control acetylcholinesterase (AChE) were searched for by segmental aneuploidy techniques. Homogenates of flies containing duplications or deletions for different segments were assayed for enzyme activity. A region on the third chromosome was found for which flies having one does consistently gave lower AChE activity than euploid flies, which were in turn had lower activity than flies with three doses. The activity differences were in the approximate ratio 1:2:3. Fine structure deletion mapping within this region revealed a very small segment for which one-dose flies have approximately half-normal activity. To obtain putative AchE-null mutations, lethal mutations within this region were assayed. Four allelic lethals have approximately half-normal activity in heterozygous condition. These lethals probably define the structural locus (symbol: Ace) for AChE.
IS THERE A GENE REGULATING THE SCUTE LOCUS ON THE THIRD CHROMOSOME OF D. MELANOGASTER?
Authors: Rendel J M 
Published: April 2021

ABSTRACT
A section of the third chromosome of D. melanogaster some 25 to 40 centimorgans long including sr was transferred from a wild-type stock selected by Latter for high scutellar bristle number into a scute stock with a large number of scutellar bristles. This segment is shown to have a large effect on the bristle numbers of wild-type flies, to reduce the strength of canalization of the scute phenotype at 4 bristles, to have little, if any, effect on bristle numbers of scute flies with less than 4 bristles but to increase the number of flies with 5 and 6 scutellar bristles in scute stocks that normally have a large number of flies with 4 bristles. It is suggested that this segment in unselected chromosomes contains a gene that regulates bristle number by repressing the scute locus and that Latter has selected a mutant of the regulator which fails to repress the action of the scute locus.
MUTATORS IN SACCHAROMYCES CEREVISIAE: MUT1–1, MUT1–2 AND MUT2–1
Authors: Gottlieb Dorma J C , Von Borstel R C 
Published: April 2021

ABSTRACT
The purpose of this study was to characterize two mutator stocks of yeast which were induced and selected on the basis of high spontaneous reversion rates of the suppressible "ochre" nonsense allele lys1-1. In the mutator stock VA-3, a single mutation, designated mut1-1, is responsible for the increase in the reversion rate of the ochre alleles lys1-1 and arg4-17. In stock VA-105, there are two separate mutator mutations. Tetrad analysis data showed these two loci are loosely linked. Based on complementation data, one of these mutations is at the same locus as mut1-1 and designated mut1-2. The second mutator of stock VA-105 was designated mut2-1. All three mutators are recessive. Both mut1-1 and mut1-2 give a high mutation rate for ochre nonsense suppressor (SUP) loci, but not for the ochre nonsense alleles. On the contrary, the mutation rates of the ochre alleles are greatly reduced. With the mutant mut2-1 there were mutations at both the lys1-1site and its suppressors; mut2-1 is as effective as mut1-2but not as effective as mut1-1 in inducing reversions of a missense mutant, his1-7. Neither mut1-1, mut1-2 nor mut2-1 were effective in inducing reversions of a putative frameshift mutation, hom3-10, or in inducing forward mutations to canavanine resistance.
GENE CONVERSION: A HITHERTO OVERLOOKED PARAMETER IN POPULATION GENETICS
Authors: Gutz Herbert , Leslie John F 
Published: April 2021

ABSTRACT
Gene conversion causes deviations from the 2:2 segregation of allele pairs in meiosis. Thus, gene conversion is a potential cause for changes of allele frequencies in populations. Equations are derived for the effects of conversion in a large random-mating population. The influence of gene conversion on allele frequencies is compared with that of spontaneous mutation and meiotic drive.
SELECTION FOR RATE AND EFFICIENCY OF LEAN GAIN IN THE RAT
Authors: Notter David R , Dickerson G E , Deshazer J A 
Published: April 2021

ABSTRACT
Full-sib family selection for rate (WP) or efficiency (WP/F) of protein gain in rats from 3 to 9 weeks of age was applied for five generations. Three rats per litter were killed to estimate carcass protein. Standardized response/cumulative selection for WP was.19±.10 for WP,.28±.10 for 3- to 9-week gain,.28±.08 for 9-week weight,.16±.08 for litter size,.22±.12 for skinning loss and -.07±.09 for fraction of protein in the live weight. Response from selection for WP/F was.18±.16 for WP/F,.20±.11 for WP,.21±.11 for weight gain,.16±.11 for 3-week weight,.21±.10 for 9-week weight, but negligible for skinning loss or body protein. Response to WP/F selection was extremely variable among generations, associated with generation differences in weight and composition at 9 weeks. Estimates of heritability from offspring-midparent regression were.20±.12 for WP and.24±.08 for WP/F. Estimates of genotype-generation environment interaction were large for growth, feed intake and skinning loss. Maternal effects were large for weaning weight, fraction of body protein and WP. Sire component genetic correlations were 1.08±.13 for WP with total gain,.92±.08 for WP/F with gross efficiency and.29±.25 for WP with WP/F. A partitional calorimeter was used to evaluate heat production of rats. Lines differed in average heat loss but not in heat loss per unit actual or metabolic weight. Response to selection has been steady for WP but probably could be improved by selecting for WP/F at a constant weight rather than a constant age.
A STUDY OF THE TRANSMISSION AND STRUCTURE OF DOUBLE STRANDED RNAs ASSOCIATED WITH THE KILLER PHENOMENON IN SACCHAROMYCES CEREVISIAE
Authors: Sweeney T Kevin , Tate Ann , Fink Gerald R 
Published: April 2021

ABSTRACT
Killer strains contain two double stranded RNAs, L and M. The M dsRNA appears to be necessary for production of a toxin and for resistance to that toxin. Mutant strains have been found that are defective in their ability to kill and in their resistance to toxin. These sensitive, non-killer strains have altered dsRNA composition. One class has no M dsRNA. Another class of sensitive, non-killers called suppressives has no M dsRNA but instead has smaller dsRNAs called S. In diploids resulting from a cross of a wild-type killer by a suppressive the transmission of the M dsRNA is suppressed by the S dsRNA. When a suppressive is crossed by a strain with no M dsRNA, the diploids and all four meiotic spores have the S dsRNA characteristic of the parental suppressive strain. Suppressive strains do not suppress each other. Intercrosses between two different suppressives yields diploids with both parental S dsRNAs. These two S dsRNAs are transmitted to all 4 meiotic progeny. Another class of mutants has been found which is defective for one of the traits but retains the other. One type, temperature-sensitive killers, has a normal dsRNA composition but is unable to kill at 30°. The other type, immunity-minus, has a complex dsRNA pattern. The immunity-minus strain is extremely unstable during mitotic growth and segregates several different types of non-killers. Analysis of the dsRNAs from wild type and the mutants by electron microscopy shows that the L, M, and S dsRNAs are linear. All strains regardless of killer phenotype appear to have the same size L dsRNA.
MAPPING OF THE HOMOTHALLIC GENES, HMα AND HM
a, IN SACCHAROMYCES YEASTS
Authors: Harashima Satoshi , Oshima Yasuji 
Published: April 2021

ABSTRACT
Two of the three homothallic genes, HMα and HM a, showed direct linkage to the mating-type locus at approximately 73 and 98 stranes (57 and 65 centimorgans [cM]), respectively, whereas, the other, HO, showed no linkage to 25 standard markers distributed over 17 chromosomes including the mating-type locus. To determine whether the HMα and HM a loci located on the left or right side of the mating-type locus, equations for three factor analysis of three linked genes were derived. Tetrad data were collected and were compared with expected values by X2 statistics. Calculations indicated that the HMα gene is probably located on the right arm at 95 stranes (65 cM) from the centromere and the HM a locus at approximately 90 stranes (64 cM) on the left arm of chromosome III.
NONBEHAVIORAL SELECTION FOR PAWNS, MUTANTS OF PARAMECIUM AURELIA WITH DECREASED EXCITABILITY
Authors: Schein Stanley J 
Published: April 2021

ABSTRACT
The reversal response in Paramecium aurelia is mediated by calcium which carries the inward current during excitation. Electrophysiological studies indicate that strontium and barium can also carry the inward current. Exposure to high concentrations of barium rapidly paralyzes and later kills wild-type paramecia. Following mutagenesis with nitrosoguanidine, seven mutants which continued to swim in the 'high-barium' solution were selected. All of the mutants show decreased reversal behavior, with phenotypes ranging from extremely non-reversing ('extreme' pawns) to nearly wild-type reversal behavior ('partial' pawns). The mutations fall into three complementation groups, identical to the pwA, pwB, and pwC genes of Kung et al. (1975). All of the pwA and pwB mutants withstand longer exposure to barium, the pwB mutants surviving longer than the pwA mutants. Among mutants of each gene, survival is correlated with loss of reversal behavior. Double mutants (A-B, A-C, B-C), identified in the exautogamous progeny of crosses between 'partial' mutants, exhibited a more extreme non-reversing phenotype than either of their single-mutant ('partial' pawn) parents.—Inability to reverse could be expected from an alteration in the calcium-activated reversal mechanism or in excitation. A normal calcium-activated structure was demonstrated in all pawns by chlorpromazine treatment. In a separate report (Schein, Bennett and Katz 1976) the results of electrophysiological investigations directly demonstrate decreased excitability in all of the mutants, a decrease due to an altered calcium activation. The studies of the genetics, the survival in barium and the electro-physiology of the pawns demonstrate that the pwA and pwB genes have different effects on calcium activation.
CHANGE IN STATE FOLLOWING TRANSPOSITION OF A REGULATORY ELEMENT OF THE ENHANCER SYSTEM IN MAIZE
Authors: Peterson Peter A 
Published: April 2021

ABSTRACT
From an original A2 allele (colored aleurone), a mutable allele, a2-m-4 1629, that changes from a2 to A2 is described. Mutability is expressed as a very distinct pattern limited to the last cell division.—The mutability of a2-m-4 1629 is autonomously controlled by an En at the a2 locus. This En, inactive on standard a testers for En, is partially active on a2-m-1, an a2 tester for En, and expresses varied levels of activity from limited to nearly full suppression of the a2-m-1 color phenotype.—When the En of the a2-m-4 1629 allele transposes from the a2 locus, it behaves, at the new position, like a standard En in triggering a2-m-1, a-m-1 and a-m(r), which express colored spots on a colorless background. The activity of En is therefore different following the change in chromosome location. This finding supports the "position" hypothesis that has been proposed to explain diverse patterns observed among controlling elements. In this case mutation is related to the terminal cell state and not to tissue differences as shown with some phase-variation regulatory elements.
ISOLATION AND CHARACTERIZATION OF X-LINKED MUTANTS OF DROSOPHILA MELANOGASTER WHICH ARE SENSITIVE TO MUTAGENS
Authors: Boyd J B , Golino M D , Nguyen T D , Green M M 
Published: April 2021

ABSTRACT
Thirteen X-linked mutants have been isolated in Drosophila melanogaster which render male and homozygous female larvae sensitive to the mutagen methyl methanesulfonate. Their characterization and preliminary assignment to functional groups is described. Four of these mutants are alleles of mei-41 (Baker and Carpenter 1972). Like previously isolated alleles of this locus, these mutants reduce fertility and increase loss and nondisjunction of the X-chromosome in homozygous females. The remaining mutants have been tentatively assigned to six functional groups (two mutants to the mus(1)101 locus, two to mus(1)102, two to mus(1)103, and one each to mus(1)104, mus(1)105, and mus(1)106). Several of the complementation groups can be distinguished on the basis of nondisjunction and cross sensitivity to mutagens. Females homozygous for the mei-41, mus(1)101 and mus(1)102 mutants exhibit elevated levels of nondisjunction. Mutants belonging to complementation groups mei-41, mus(1)101, and mus(1)104 are sensitive to nitrogen mustard (HN2) in addition to their MMS sensitivity. Among these mutants there is currently a direct correlation between sensitivity to HN2, sensitivity to 2-acetylaminofluorene and a deficiency in post-replication repair (Boyd and Setlow 1976). Only the mei-41 mutants are hypersensitive to UV radiation, although several of the mutants exhibit sensitivity to Y-rays. Semidominance is observed in female larvae of the mei-41, mus(1)104, and mus(1)103 mutants after exposure to high concentrations of MMS. The properties of the mutants generally conform to a pattern which has been established for related mutants in yeast. Additional properties of these mutants are summarized in Table 9.
GENETIC HETEROGENEITY WITHIN ELECTROPHORETIC "ALLELES" OF XANTHINE DEHYDROGENASE IN DROSOPHILA PSEUDOOBSCURA
Authors: Singh R S , Lewontin R C , Felton A A 
Published: April 2021

ABSTRACT
An experimental plan for an exhaustive determination of genic variation at structural gene loci is presented. In the initial steps of this program, 146 isochromosomal lines from 12 geographic populations of D. pseudoobscura were examined for allelic variation of xanthine dehydrogenase by the serial use of 4 different electrophoretic conditions and a heat stability test. The 5 criteria revealed a total of 37 allelic classes out of the 146 genomes examined where only 6 had been previously revealed by the usual method of gel electrophoresis. This immense increase in genic variation also showed previously unsuspected population differences between the main part of the species distribution and the isolated population of Bogotá, Colombia, in conformity with the known partial reproductive isolation of the Bogotá population. The average heterozygosity at the Xdh locus is at least 72% in natural populations. This result, together with the very large number of alleles segregating and the pattern of allelic frequencies, has implications for theories of genetic polymorphism which are discussed.
ROLE OF DNA SEQUENCES IN GENETIC RECOMBINATION IN THE ISO-1-CYTOCHROME c GENE OF YEAST. II. COMPARISON OF MUTANTS ALTERED AT THE SAME AND NEARBY BASE PAIRS
Authors: Moore Carol W , Sherman Fred 
Published: April 2021

ABSTRACT
X-ray-induced mitotic recombination rates and spontaneous meiotic recombination rates have been determined in two-point crosses of various defined cyc1 mutants of the yeast Saccharomyces cerevisiae. All but one of the 17 cyc1 mutants chosen for this study contained either the addition, deletion or substitution of single base-pairs located within a defined segment of the gene that corresponds to the 11 amino acid residues at the amino terminus of iso-1-cytochrome c; approximately half of these mutants had alterations of the AUG initiation codon, some at the same base pair. Up to 66-fold differences in X-ray-induced recombination rates were observed when the same cyc1 mutant was crossed to cyc1 mutants having different alterations in the AUG initiation codon; over a ten-fold difference was observed in series of homologous crosses involving mutants with different changes at the same base-pair. Recombination rates that were associated with specific cyc1 mutants co-segregated with the particular alleles following meiosis, and comparable recombination patterns were also observed for independently isolated, identical mutations. With the mutants used in this study, the frequencies of meiotic recombination did not differ as markedly, suggesting a dissimilar dependence on specific DNA sequences for these two modes of recombination. These disproportionalities of recombination rates suggest that the nature of the mismatched bases influences the recombination process, but not in a way that can be simply interpreted.