bluuebunny/crossref_metadata_2025_split huggingface dataset:
GENIC HETEROGENEITY AT TWO ALCOHOL DEHYDROGENASE LOCI IN DROSOPHILA PSEUDOOBSCURA AND DROSOPHILA PERSIMILIS
Authors: Coyne Jerry A , Felton Alexander A 
Published: April 2021

ABSTRACT
A sequential electrophoretic survey of the second chromosome loci, alcohol dehydrogenase-6 (Adh-6) and octanol dehydrogenase (Odh), was performed on 147 isochromosomal lines of Drosophila pseudoobscura and 60 lines of its sibling species, D. persimilis. Gels run with a variety of acrylamide concentrations and buffer pH's revealed the presence of 18 alleles of Adh-6 in the two species, where only eight had been previously detected by conventional electrophoretic methods. Only two alleles were added with our techniques to the previous total of nine in both species at the largely monomorphic Odh locus. Both enzymes show a predominance of one allele, with the other variants being fairly rare. There was no evidence of increased genetic divergence between the two species, but we found a striking increase in differentiation of Adh-6 alleles between the main body of D. pseudoobscura populations and the conspecific isolate from Bogotá, Colombia. These results are compared with our previous surveys of xanthine dehydrogenase in these species and discussed in reference to theories of genic polymorphism.
GENERALIZED TRANSDUCTION IN CAULOBACTER CRESCENTUS
Authors: Ely Bert , Johnson Reid C 
Published: April 2021

ABSTRACT
Two closely related bacteriophage, φCr30 and φCr35, are the first bacteriophage shown to mediate generalized transduction in Caulobacter crescentus. Unlike most other transducing phage, they are virulent and do not form any sort of lysogenic relationship with their host. However, they are rather inefficient at adsorption, so that transductants have a good chance of survival. The phage particles have a head 80 nm in diameter and a contractile tail 140 nm in length. Procedures for growth and transduction with φCr30 are relatively simple; thus, it will be of great value for the genetic analysis of C. crescentus.
MAINTENANCE OF A "PARASITIC" B CHROMOSOME IN THE GRASSHOPPER MELANOPLUS FEMUR-RUBRUM
Authors: Nur Uzi 
Published: April 2021

ABSTRACT
About 10-15% of the males and females of the grasshopper Melanoplus femur-rubrum collected near Rochester, New York, possessed a supernumerary B chromosome. The frequency of the B chromosome remained fairly constant during the years 1971-1974. The B chromosome was shown previously to be transmitted at a rate of about 0.5 and 0.8 by 1B males and females, respectively. This study was designed to determine the forces preventing the B chromosome from increasing in frequency due to the high rate of transmission by the females. Eighty inseminated females collected in the wild were analyzed cytologically together with their embryos (10-20 per female). Ten of the 80 females had a B chromosome, and they transmitted it at a rate of about 0.75. Among the 983 embryos analyzed, 0.141 had one B, 0.007 had two, and the mean number of B chromosomes per embryo was 0.155. The frequency of the B chromosome in the sperm pool (0.061) was consistent with a 0.5 rate of transmission. Individuals with two B chromosomes apparently have low viability, because about six were expected, but none was found among 851 adult males and females examined. The data suggest that the viability of the 1B individuals was only about 0.86 that of the OB individuals. There was no evidence that the B chromosome increased the fecundity of either the 1B males or females. It was concluded, therefore, that the B chromosome reduced the fitness of all the individuals carrying it and was thus "parasitic," and that it was maintained in the population only because of its high transmission rate. The maintenance of other B chromosomes with high transmission rates is reviewed.
THE GENETICS OF α-HYDROXYACID OXIDASE AND ALCOHOL DEHYDROGENASE IN THE MOUSE: EVIDENCE FOR MULTIPLE GENE LOCI AND LINKAGE BETWEEN Hao-2 AND Adh-3
Authors: Holmes Roger S 
Published: April 2021

ABSTRACT
Electrophoretic polymorphisms for stomach alcohol dehydrogenase (ADH-C2) and kidney L-α-hydroxyacid oxidase (HAOX-B4) have been identified in an Asian subspecies of mouse, Mus musculus castaneous. These variants are inherited in a normal Mendelian fashion with two alleles in each case showing codominant expression. The structural gene loci for those enzymes (Adh-3 and Hao-2, respectively) are apparently linked (17.6% recombinants) in this organism, whereas the multiple gene loci for HAOX, Hao-1 (encoding the A4 liver isozyme) and Hao-2, exhibited independent segregation and are unlinked (50% recombinants). Evidence is presented for 3 ADH loci: Adh-1, encoding liver ADH-A2 which exhibits high activity with ethanol (Selander, Hunt and Yang 1969; Adh-2, liver and stomach ADH-B 2 using 2-hexene-1-ol as substrate; and Adh-3, stomach ADH-C 2 using both benzyl alcohol and 2-hexene-1-ol as substrate.
FITNESS EFFECTS OF EMS-INDUCED MUTATIONS ON THE X CHROMOSOME OF DROSOPHILA MELANOGASTER. II. HEMIZYGOUS FITNESS EFFECTS
Authors: Mitchell Joyce A , Simmons Michael J 
Published: April 2021

ABSTRACT
X chromosomes mutagenized with EMS were tested for their effects on the fitness of hemizygous carriers. The tests were carried out in populations in which treated and untreated X chromosomes segregated from matings between males and attached-X females; the populations were maintained for several generations, during which time changes in the frequencies of the treated and untreated chromosomes were observed. From the rates at which the frequencies changed, the fitness effects of the treated chromosomes were determined. It was found that flies hemizygous for a mutagenized chromosome were 1.7% less fit per mm EMS treatment than those hemizygous for an untreated chromosome. Since the same flies were only 0.5% per m m less viable than their untreated counterparts, the total fitness effect of an X chromosome carrying EMS-induced mutants is three to four times greater than its viability effect. By comparing the heterozygous effect of a mutagenized X chromosome on fitness with the corresponding hemizygous effect, the dominance value for the chromosome is estimated to be about 0.25.
INTERNUCLEAR GENETIC TRANSFER IN VEGETATIVE DIKARYONS OF SCHIZOPHYLLUM COMMUNE: I. DI-MON MATING ANALYSIS
Authors: Leonard Thomas J , Dick Stanley , Gaber Richard F 
Published: April 2021

ABSTRACT
A series of hemi-compatible dikaryon × monokaryon (di-mon) matings was designed to determine whether there was any genetic interaction between the dikaryotic nuclei. One of the nuclei in each dikaryon was known to carry a recessive gene (mnd) that promoted the development of an abnormal growth form, mound. Dikaryons containing both m n d f and innd nuclei produced mosaic colonies that consisted of three distinct kinds of hyphae: mound, fruiting body, and vegetative (devoid of any multihyphal structure). When dikaryotic hyphae from each of these morphological regions were used in di-mon matings, the genetic and developmental characteristics of the selected nuclear types were examined in the resulting derived dikaryons. The results showed that fruiting-body and vegetative cells contained the expected mnd and mnd+ nuclei. Dikaryotic mound hyphae, however, contained only mnd nuclei. In a manner as yet unresolved, but clearly dependent on the presence of the mnd allele, the mnd+ allele of a wild nucleus was altered to, or acquired, the mnd allele. A number of hypotheses were considered to explain the genetic event(s) that generates [mnd + mnd*] dikaryotic cells from [mnd+ + mnd] cells, but none was found to be entirely satisfactory.
A GENETIC LOCUS HAVING TRANS AND CONTIGUOUS CIS FUNCTIONS THAT CONTROL THE DISPROPORTIONATE REPLICATION OF RIBOSOMAL RNA GENES IN DROSOPHILA MELANOGASTER
Authors: Procunier James D , Tartof Kenneth D 
Published: April 2021

ABSTRACT
The results of deficiency mapping experiments reveal the presence of a compensatory response (c r +) locus that is located distal to the cluster of ribosomal RNA (rRNA) genes and is responsible for disproportionately replicating these genes when cr+ locus is present in a single dose, as in X/O males or X / SC4 - Sc8 females. The cr+ locus is novel in that it exhibits both trans and contiguous cis acting properties in somatic cells. It acts in trans to detect the presence of its partner locus in the opposite homolog, and if that partner locus is absent, it acts in cis to drive the disproportionate replication of those rRNA genes (rDNA) that are contiguous with it. The ability of cr+ to function is independent of the number of ribosomal RNA genes present. Furthermore, it can be shown that the cr+ locus is not required for the magnification or reduction of germ line rDNA. Finally, the implications of cr+ for position-effect variegation and the apparent reversion of the abnormal oocyte (abo) phenotype are discussed.
KILLER PHENOMENON IN USTILAGO MAYDIS: THE ORGANIZATION OF THE VIRAL GENOME
Authors: Koltin Y , Kandel J S 
Published: April 2021

ABSTRACT
The double-stranded RNA content, the production of inactive killer protein, and the presence of virus-like particles were examined in induced nonkiller mutants and nonkiller progeny from a cross between a killer strain and a sensitive strain. A correlation between the loss of the 0.7 × 106 daltons dsRNA of the Ustilago maydis P6 virus and the lack of synthesis of the killer protein was established. In vitro and in vivo complementation between nonkiller strains provide additional support for the suggestion that the 0.7 × 106 daltons dsRNA is related to the killer function. The coding capacity of the various species of dsRNA is discussed in relation to their possible function.
DEVELOPMENTAL ANALYSIS OF THE ACHAETE-SCUTE SYSTEM OF DROSOPHILA MELANOGASTER
Authors: García-Bellido A , Santamaria P 
Published: April 2021

ABSTRACT
The interpretation of the wild-type function of a gene depends on our knowledge of the phenotype caused by its absence. We have first defined the genetic extent of the achaete-scute system by studying the phenotype of different terminal and intercalary deficiencies including these genes. When these deficiencies were lethal, we have defined the phenoeffective phase of lethality and studied their phenotype in genetic mosaics (gynandromorphs and mitotic recombination clones). The achaete-scute system affects two functions, one necessary for the differentiation of the embryonic (central?) nervous system and the other necessary for the differentiation of peripheral nervous elements of the chaetes and sensillae of the adult cuticle. The possibility that these functions correspond to differential expression of a single mechanism is discussed.
CYTOGENETIC LOCALIZATION OF THE ACID PHOSPHATASE-1 GENE IN DROSOPHILA MELANOGASTER
Authors: Morrison William J , MacIntyre Ross J 
Published: April 2021

ABSTRACT
A translocation in which a segment of chromosome 3 is inserted into the Y chromosome was found to contain the acid phosphatase-1 gene (Acph-1). In flies hyperploid for that gene, acid phosphatase-1 levels are proportional to the dose of the gene. The locus is placed within the salivary chromosome subdivisions 99D and 99E on the basis of its inclusion in the translocated segment and on the previous placement of the claret locus. Several chromosomal rearrangements involving heterochromatic breakpoints and euchromatic breakpoints adjacent to 99D-99E were tested for possible position-effect variegation of acid phosphatase-1. No decrease in the synthesis of the electrophoretic subunit encoded by the relocated gene was observed within any of the rearrangements.
INVERSIONS FAIL TO ACCOUNT FOR ALLOZYME CLINES
Authors: Voelker R A , Cockerham C Clark , Johnson F M , Schaffer H E , Mukai Terumi , Mettler L E 
Published: April 2021

ABSTRACT
Allozyme and inversion data from natural populations of Drosophila melanogaster from the eastern United States were analyzed to determine whether the clines at allozyme loci are due to nonrandom associations with common cosmopolitan inversions. All inversions show strong clines. Clines were large and significant for half of the eight allozyme loci. An analysis of the contribution of inversions to clines of allozyme genes revealed three outcomes: the inversion cline (1) enhanced the allozyme cline, but was only partly responsible, (2) reduced the allozyme cline, and (3) had no effect. The allozyme clines were mainly determined by the pattern of allele frequencies within the chromosomal arrangements. Consequently, it was concluded that allozyme clines would exist in the absence of inversion clines.
DYNAMICS OF A LACTATE DEHYDROGENASE POLYMORPHISM IN THE WOOD LOUSE PORCELLIO SCABER LATR.: EVIDENCE FOR PARTIAL ASSORTATIVE MATING AND HETEROSIS IN NATURAL POPULATIONS
Authors: Sassaman Clay 
Published: April 2021

ABSTRACT
Electrophoretic separation of lactate dehydrogenase (LDH) of Porcellio scaber from 14 natural populations in California, and one each in Oregon, Delaware and Massachusetts, indicates a biallelic polymorphism. Phenotypes are recovered from laboratory matings of virgin females in frequencies agreeing with simple Mendelian inheritance, and the frequency distributions of phenotypes in natural populations are typically in agreement with the appropriate Hardy-Weinberg distributions for these same populations. The same allele predominates in all natural populations examined. Temporal stability within populations suggests that the polymorphism is at, or near, equilibrium. The spatial distribution of allele frequencies, however, is apparently mosaic. Abrupt discontinuities in gene frequency over short distances (50 m to 1 km) suggest that interpopulation migration is insufficient to swamp local differences in gene frequency. Analysis of the transmission dynamics of the polymorphism in natural populations using mother-offspring genotype comparisons suggests that the allelic frequencies of transmitted male gametes are not independent of female genotype. Specifically, the observed mating scheme in natural populations appears to be partially assortative. Comparisons of progeny genotype distributions with yearling (or adult) genotype distributions from the same populations indicate a superior post-partum viability of heterozygous individuals relative to homozygotes. The distortion of progeny genotypic distributions created by assortment is thus apparently counteracted by subsequent heterosis.
A COMPARISON OF THE GENETIC INFRASTRUCTURE OF THE YE'CUANA AND THE YANOMAMA: A LIKELIHOOD ANALYSIS OF GENOTYPIC VARIATION AMONG POPULATIONS
Authors: Smouse Peter E , Ward Richard H 
Published: April 2021

ABSTRACT
A general procedure is described for measuring and testing population differences in gametic frequencies. The total dispersion among populations is subdivided in hierarchical fashion. The multiple-locus treatment is simply the sum of the single-locus analyses, provided gametic equilibrium obtains among the loci. In the event that gametic equilibrium does not obtain, correlations among loci need to be dealt with.—The analysis is then used to examine the genetic infrastructure of two Indian tribes from South America, the Ye'cuana (Makiritare) and the Yanomama. From historical evidence, we may identify several "clusters" of villages within each tribe. The demographic and cultural practices affecting village formation and the maintenance of peer integrity are rather different in these tribes, however, and lead us to postulate rather different patterns of genetic variation among villages. Analyses of five codominant two-allele loci, four dominant two-allele loci and two complex loci (with four codominant haplotypes each) demonstrate that Yanomama clusters are more disparate than Ye'cuana clusters, as would have been predicted on sociocultural grounds.
CYTOPLASMIC MALE STERILITY IN NICOTIANA, RESTORATION OF FERTILITY, AND THE NUCLEOLUS
Authors: Gerstel D U , Burns J A , Burk L G 
Published: April 2021

ABSTRACT
Plants with the cytoplasm of Nicotiana repanda and the chromosomes of N. tabacum produce nonfunctional and feminized anthers. Introduction of a satellited fragment chromosome, apparently derived from N. repanda, restores normal anthers and pollen fertility. The fragment is somatically stable and addition-homozygotes transmit it to the great majority of their offspring. Cells with the fragment exhibit amphiplasty, i.e., in plants having one or two fragments, nucleolar organizers of N. tabacum are suppressed and the nucleoli are entirely or largely produced by the fragments. Formation of nucleoli by organizers from N. repanda in N. repanda cytoplasm may thus be a condition for male fertility. The manner in which nucleoli may influence the development of originally indeterminate sex primordia is discussed. Further cytological studies of cytoplasmically male-sterile plants and restorer chromosomes are needed to decide whether the observed relationship is of functional significance or merely accidental.
GENETIC RECOMBINATION AND CLONAL SELECTION IN DROSOPHILA MERCATORUM
Authors: Annest Joseph L , Templeton Alan R 
Published: April 2021

ABSTRACT
Discrete and continuous generation unisexual populations were established from parthenogenetic D. mercatorum females heterozygous for five visible loci and one electrophoretic locus, which marked all five major chromosome arms. In the first impaternate generation of the discrete generation population, all thirty-two possible recombinant genotypes for the five visible markers were displayed. However, 99% of these individuals were homozygous for all gene markers due to the predominant mode of parthenogenesis called nuclear duplication. Many of these homozygous individuals gave rise to isogenic clones that were compelled to compete with each other in subsequent generations. A detailed analysis of the genetic response of this clonal population showed strong evidence for selection involving epistatic interactions between linked and unlinked loci throughout the genome. The unit of selection is described as being determined as early as the zygotic stage of development.
ALLELIC VARIATION AT THE LEVEL OF INTRAGENIC RECOMBINATION
Authors: Freeling Michael 
Published: April 2021

ABSTRACT
This report examines five different naturally occurring alcohol dehydrogenase-1 alleles via the recombinational behavior of Adh1 - mutants induced within them. Twenty-two biochemically characterized Adh1 - mutants have been assessed for ability to recombine intragenically, using data generated by specifically staining for the presence of ADH in pollen grains. Each of the five naturally occurring Adh1 progenitor isoalleles appears unique. Allelic variation exists in (1) the rate of intragenic recombination sustained by an allele, and (2) the pattern of recombinational success or failure based on the ancestry of each mutant in a heteroallelic pair. In other words, we find quantitative and qualitative Adh1 allelic variation at the level of intragenic recombination. I have experimentally excluded several explanations for recombinational restriction. These results will be related to the structure, function and naturally occurring variability of the gene in higher organisms. Specifically, the "recon" (unit of recombination) has been resurrected as a potentially useful unit of natural selection. The reasonableness of several genres of hypotheses in evolutionary/population genetics, particularly those involving linkage disequilibrium, is called into question.
DIPLOIDS OF CLOCK MUTANTS OF CHLAMYDOMONAS REINHARDI
Authors: Bruce Victor G , Bruce Nancy C 
Published: April 2021

ABSTRACT
Diploids constructed from three clock mutants of Chlamydomonas have been analyzed. In the haploid state, these mutations all lengthen the clock period, and they are at separate genetic loci. One is recessive, one dominant, and one is probably incompletely dominant to their respective wild-type alleles.
A MEIOTIC UV-SENSITIVE MUTANT THAT CAUSES DELETION OF DUPLICATIONS IN NEUROSPORA
Authors: Newmeyer Dorothy , Galeazzi Donna R 
Published: April 2021

ABSTRACT
The meiotic-3 (mei-3) mutant of Neurospora crassa has several effects: (1) When homozygous, it almost completely blocks meiosis and ascospore formation, (2) it is sensitive to UV, (3) its growth is inhibited by histidine and, (4) it increases the instability of nontandem duplications. This was shown for duplications produced by five different rearrangements and was demonstrated by two different criteria. The effects on meiosis and duplication instability are expressed strongly at 25°; the effects on sensitivity to UV and to histidine are expressed strongly at 38.5° but only slightly at 25°. Nevertheless, all four effects were shown to be due to a single gene. mei-3 is not allelic with previously reported UV-sensitive mutants.—Two other results were obtained that are not necessarily due to mei-3: (1) A cross involving mei-3 produced a new unlinked meiotic mutant, mei-4, which is not sensitive to UV or histidine, and (2) a burst of several new mutants occurred in a different mei-3 stock, including a partial revertant of mei-3.—mei-3 has previously been shown to cause frequent complete loss of a terminal duplicate segment, beginning exactly at the original rearrangement breakpoint. Possible mechanisms are discussed by which a UV-sensitive mutant could cause such precise deletions.
INDIRECT SUPPRESSION IN CAENORHABDITIS ELEGANS
Authors: Riddle Donald L , Brenner S 
Published: April 2021

ABSTRACT
Two cases of indirect suppression have been characterized. One case involves suppressors compensating for defects in muscle structure. Nine independent suppressor mutations were judged to lie in a single suppressor gene, sup-3. Suppression is dominant, but dose dependent, and results in improved locomotion, as well as in an increase in the ability of mutant animals to lay eggs. Mutations in six genes known to affect muscle structure were tested for suppression by representative sup-3 mutations. Alleles of three of the six genes are suppressed, two of which are known to code for thick filament proteins. One suppressor allele was identified as a deletion by genetic criteria. A second case of indirect suppression is not associated with muscle defects, but involves two mutant genes producing uncoordinated phenotypes very similar to one another. As in the first case, suppression is dominant but dose dependent and is not allele specific.
RANK-ORDER SELECTION IS CAPABLE OF MAINTAINING ALL GENETIC POLYMORPHISMS
Authors: Wills Christopher 
Published: April 2021

ABSTRACT
The fitness of organisms may be due chiefly to a fitness curve imposed on their ranking in the population with respect to heterozygosity. If this is so, then the number of polymorphisms that can be retained at a particular selective equilibrium increases as the square of the population size. All of the genetic variation that we currently observe and infer to exist can probably be maintained by selection in a population of about 105 individuals. Selection acting in this way is so strong that these polymorphisms can be expected to behave very differently from neutral ones.
EXPERIMENTAL EVOLUTION OF A NEW ENZYMATIC FUNCTION. II. EVOLUTION OF MULTIPLE FUNCTIONS FOR EBG ENZYME IN E. COLI
Authors: Hall Barry G 
Published: April 2021

ABSTRACT
The evolution of ebgo enzyme of Escherichia coli, an enzyme which is unable to hydrolyze lactose, lactulose, lactobionate, or galactose-arabinoside effectively, has been directed in successive steps so that the evolved enzyme is able to hydrolyze these galactosides effectively. I show that in order for a strain of E. coli with a lacZ deletion to evolve the ability to use lactobionate as a carbon source, a series of mutations must occur in the ebg genes, and that these mutations must be selected in a particular order. The ordered series of mutations constitutes an obligatory evolutionary pathway for the acquisition of a new function for ebgo enzyme. A comparison of newly evolved strains with parental strains shows that when ebg enzyme acquires a new function, its old functions often suffer; but that in several cases old functions are either unaffected or are improved. I conclude that divergence of functions catalyzed by an enzyme need not require gene duplication.