bluuebunny/crossref_metadata_2025_split huggingface dataset:
COMPLEMENTATION AND NONCOMPLEMENTATION AMONG NONALLELIC MUTATIONS ALTERING DEVELOPMENT IN SCHIZOPHYLLUM COMMUNE
Authors: Klein Keith K , Deppe Carol S 
Published: January 2021

ABSTRACT
Mutations resistant to compounds that alter the development of Schizophyllum commune (cyclic adenosine monophosphate, caffeine and imidazole) were selected. These mutations defined four genes, car (cAMP resistance), caf-1 and caf-2 (caffeine resistance) and imr (imidazole resistance). The mutations were found to be noncomplementing in certain pairs when tested against each other and against two previously isolated developmental mutations, B-con and sep (septateless), in fully compatible, forced heterokaryons. The pattern of complementation in fully compatible diploids showed noncomplementation only between allelic mutations, except for one case, imr vs. car.
GENETIC MAPPING OF CAENORHABDITIS ELEGANS COLLAGEN GENES USING DNA POLYMORPHISMS AS PHENOTYPIC MARKERS
Authors: Cox George N , Carr Stephen , Kramer James M , Hirsh David 
Published: January 2021

ABSTRACT
In Caenorhabditis elegans collagens comprise a dispersed family of 40—150 genes, the majority of which probably code for collagen proteins found in the animal's cuticle. The conserved (Gly-X-Y)n triple helix coding sequence of collagen genes has facilitated the isolation of a large number of C. elegans collagen genes by recombinant DNA methods. We have begun a study of the chromosomal organization of these genes by screening laboratory strains of C. elegans for DNA polymorphisms in the regions surrounding collagen genes. Polymorphisms near seven genes have been identified and have been used as phenotypic markers in genetic crosses to assign the genes to linkage groups II, III, IV, and X. Four genes are shown by multifactor crosses to map to a 2—3 map unit interval between unc-24 and unc-22 on chromosome IV.
VARIATION IN THE MAJOR URINARY PROTEIN MULTIGENE FAMILY IN WILD-DERIVED MICE
Authors: Sampsell Bonnie M , Held William A 
Published: January 2021

ABSTRACT
The levels of expression and genomic organization of genes coding for the major urinary proteins (MUPs) were examined in several stocks of wild-derived mice. Levels of MUP mRNA in the liver varied considerably with M. musculusBrno and M. castaneus males having several-fold more MUP RNA than inbred C57BL/6 males, whereas M. hortulanus, M. caroli and M. cervicolor displayed levels much lower than C57BL/6. Analysis of RNA with MUP cDNAs specific to two different subfamilies of MUP genes revealed that M. caroli and M. cervicolor primarily expressed a MUP mRNA that was less abundant in C57BL/6, suggesting differential expression of subfamilies of genes within the MUP multigene complex. Although inbred males usually have five-fold more MUP mRNA than inbred females, male to female ratios for wild-derived stocks ranged from one to several hundred. Southern blots of genomic DNA hybridized to MUP subfamily probes revealed differences in restriction fragment sizes as well as possible variation in the number of MUP genes in some species. Analysis of urinary proteins from hybrids between C57BL/6 and M. spretus suggested that low MUP expression in M. spretus females was due to cis-acting genetic elements.
SELECTION WITH PARTIAL SELFING. I. MASS SELECTION
Authors: Wright A J , Cockerham C Clark 
Published: January 2021

ABSTRACT
The expected responses to mass selection carried out before or after reproduction in a population whose members all have a fixed probability of self pollination (s) are formulated using covariances of relatives and their component quadratic functions for a model with arbitrary additive and dominance effects. The response measured in the first generation offspring after selection (immediate gain) can differ from that retained when the population has regained equilibrium (permanent gain). The population mean behaves in a predictable manner during the return to equilibrium, and its value at any time can be predicted from earlier generations. The permanent gain from selection after reproduction is always (1 + s)/2 times as large as that from selection before reproduction, but the relationship of the immediate gains depends on the genetic model assumed.—Numerical analysis applied to a model with two alleles per locus and varying allele frequencies, dominance ratios and numbers of loci showed that the proportion of the immediate gain retained at equilibrium was reduced with the large inbreeding depression associated with increasing dominance levels and numbers of loci and was generally lower for selection after reproduction than before. In the absence of information as to the magnitude of genetic variances and inbreeding depression in species reproducing by partial selfing, the importance of this phenomenon is unknown.
THE SAMPLING DISTRIBUTION OF LINKAGE DISEQUILIBRIUM UNDER AN INFINITE ALLELE MODEL WITHOUT SELECTION
Authors: Hudson Richard R 
Published: January 2021

ABSTRACT
The sampling distributions of several statistics that measure the association of alleles on gametes (linkage disequilibrium) are estimated under a two-locus neutral infinite allele model using an efficient Monte Carlo method. An often used approximation for the mean squared linkage disequilibrium is shown to be inaccurate unless the proper statistical conditioning is used. The joint distribution of linkage disequilibrium and the allele frequencies in the sample is studied. This estimated joint distribution is sufficient for obtaining an approximate maximum likelihood estimate of C = 4Nc, where N is the population size and c is the recombination rate. It has been suggested that observations of high linkage disequilibrium might be a good basis for rejecting a neutral model in favor of a model in which natural selection maintains genetic variation. It is found that a single sample of chromosomes, examined at two loci cannot provide sufficient information for such a test if C &lt; 10, because with C this small, very high levels of linkage disequilibrium are not unexpected under the neutral model. In samples of size 50, it is found that, even when C is as large as 50, the distribution of linkage disequilibrium conditional on the allele frequencies is substantially different from the distribution when there is no linkage between the loci. When conditioned on the number of alleles at each locus in the sample, all of the sample statistics examined are nearly independent of λ = 4Nμ, where μ is the neutral mutation rate.
STATISTICS OF NATURAL POPULATIONS. II. ESTIMATING AN ALLELE PROBABILITY IN FAMILIES DESCENDED FROM CRYPTIC MOTHERS
Authors: Arnold Jonathan , Morrison Melvin L 
Published: January 2021

ABSTRACT
In population studies, adults are frequently difficult or inconvenient to identify for genotype, but a family profile of genotypes can be obtained from an unidentified female crossed with a single unidentified male. The problem is to estimate an allele frequency in the cryptic parental gene pool from the observed family profiles. For example, a worker may wish to estimate inversion frequencies in Drosophila; inversion karyotypes are cryptic in adults but visible in salivary gland squashes from larvae. A simple mixture model, which assumes the Hardy-Weinberg law, Mendelian laws and a single randomly chosen mate per female, provides the vehicle for studying three competing estimators of an allele frequency. A simple, heuristically appealing estimator called the Dobzhansky estimator is compared with the maximum likelihood estimator and a close relative called the grouped profiles estimator. The Dobzhansky estimator is computationally simple, consistent and highly efficient and is recommended in practice over its competitors.
MAPPING CDC MUTATIONS IN THE YEAST S. Cerevisiae BY RAD52-MEDIATED CHROMOSOME LOSS
Authors: Hanic-Joyce Pamela J 
Published: January 2021

ABSTRACT
Using the chromosome loss-mapping method of Schild and Mortimer, I have mapped several new temperature-sensitive mutations that define five CDC genes. Modified procedures were used to facilitate mapping temperature-sensitive mutations in general, and these modifications are discussed. The mutations were assigned to specific chromosomes by chromosome loss procedures, and linkage relationships were determined subsequently by standard tetrad analysis. Four of the mutations define new loci. The fifth mutation, cdc63-1, is shown to be allelic to previously known mutations in the PRT1 gene.
FURTHER CHARACTERIZATION OF GENETIC ELEMENTS ASSOCIATED WITH THE SEGREGATION DISTORTER PHENOMENON IN DROSOPHILA MELANOGASTER
Authors: Sharp Cecil B , Hilliker Arthur J , Holm David G 
Published: January 2021

ABSTRACT
Segregation Distorter, SD, associated with the second chromosome of Drosophila melanogaster, is known to cause sperm bearing the non-SD homologue to dysfunction in heterozygous males. In earlier studies, using different, independently derived, SD chromosomes, three major loci were identified as contributing to the distortion of segregation ratios in males. In this study the genetic components of the SD-5 chromosome have been the subjects of further investigation, and our findings offer the following information. Crossover analysis confirms the mapping of the Sd locus to a position distal to but closely linked with the genetic marker pr. Spontaneous and radiation-induced recombinational analyses and deficiency studies provide firm support to the notion that the Rsp(Responder) locus lies within the proximal heterochromatin of chromosome 2, between the genetic markers lt and rl and most likely in the heterochromatin of the right arm. The major focus of this study, however, has been on providing a better definition of the genetic properties of the Enhancer of SD [E(SD)]. Our findings place this locus within the region of the two most proximal essential genes in the heterochromatin of the left arm of chromosome 2. Moreover, our analysis reveals a probable association of the E(SD) locus with a meiotic drive independent of that caused by Sd.
DEVELOPMENTAL GENETICS OF THE 2C-D REGION OF THE DROSOPHILA X CHROMOSOME
Authors: Perrimon Norbert , Engstrom Lee , Mahowald Anthony P 
Published: January 2021

ABSTRACT
We have conducted a genetic and developmental analysis of genes within the 2C-D area of the X chromosome. Phenotypes of 33 mutations representing nine adjacent complementation groups including eight recessive lethals and one visible homeotic mutation (polyhomeotic) are described. Germline clonal analysis of the eight zygotic lethals has revealed three types of gene requirements: (1) normal activity at two pupal lethal loci (corkscrew and C204) and one larval lethal locus (ultraspiracle) is required for normal embryogenesis; (2) normal activity at three larval lethal loci (DF967, VE651 and Pgd) is required for normal oogenesis; and (3) activity at only one locus (EA82), a larval lethal, appears to have no maternal requirement. Ambiguous results were obtained for the GF316 lethal complementation group. Analysis of mitotic figures of the pupal lethals indicates that C204 disrupts an essential mitotic function. This result correlates with the preblastoderm arrest observed among embryos derived from germline clones of C204. Embryos derived from germline clones of corkscrew (csw) exhibit a "twisted" phenotype. The recessive lethal ultraspiracle (usp) disrupts the organization of the posterior tip of the larva both zygotically and maternally: second instar usp/Y larvae derived from heterozygous usp/+ mothers possess an extra set of spiracles, whereas usp/Y embryos derived from females possessing a germline clone (usp/usp) exhibit a localized ventral defect in the ninth or posterior eighth abdominal segment. Analysis of the phenotypes of deficiency-hemizygous embryos indicates the presence of an embryonic zygotic lethal locus, as yet unidentified, which produces central nervous system and ventral hypoderm degeneration. Additional information on the genetic organization of loci within the adjacent 2E area are also described. The implications of this analysis to our understanding of the maternal of zygotic lethal loci in development are discussed.
NATURAL SELECTION WITH NUCLEAR AND CYTOPLASMIC TRANSMISSION. II. TESTS WITH DROSOPHILA FROM DIVERSE POPULATIONS
Authors: Clark Andrew G 
Published: January 2021

ABSTRACT
Observations of intraspecific variation in organelle DNA have prompted a renewed interest in the evolutionary consequences of cytoplasmically transmitted factors. Attempts to quantify the significance of cytoplasmic effects are frequently limited by the difficulty in partitioning the cause of reciprocal cross differences among a series of possibilities. In the experiment reported here the nuclear genomes of a set of six lines of Drosophila melanogaster from diverse geographic locations were replaced in a series of cytoplasms. The segregation of the SM5 balancer chromsome was scored in a factorial design, and the data allowed a partitioning of variance such that cytoplasmic effects were distinguished from maternal effects and meiotic drive. An attempt was made to avoid the confounding problem of hybrid dysgenesis by performing the entire experiment (including chromosomal extractions) in a P cytotype. Results indicated a significant contribution of cytoplasm to the variance in SM5 segregation. Error variance showed an increasing trend as the experiment proceeded, and additional tests indicated that this was due to an accumulation of chromosomal mutations. These findings are interpreted in light of the population genetic theory that addresses the maintenance of cytoplasmic polymorphism.
LOCALIZATION OF ACTION OF THE IS50-ENCODED TRANSPOSASE PROTEIN
Authors: Phadnis Suhas H , Sasakawa Chihiro , Berg Douglas E 
Published: January 2021

ABSTRACT
The movement of the bacterial insertion sequence IS50 and of composite elements containing direct terminal repeats of IS50 involves the two ends of IS50, designated O (outside) and I (inside), which are weakly matched in DNA sequence, and an IS50 encoded protein, transposase, which recognizes the O and I ends and acts preferentially in cis. Previous data had suggested that, initially, transposase interacts preferentially with the O end sequence and then, in a second step, with either an O or an I end. To better understand the cis action of transposase and how IS50 ends are selected, we generated a series of composite transposons which contain direct repeats of IS50 elements. In each transposon, one IS50 element encoded transposase (tnp +), and the other contained a null (tnp -) allele. In each of the five sets of composite transposons studied, the transposon for which the tnp + IS50 element contained its O end was more active than a complementary transposon for which the tnp - IS50 element contained its O end. This pattern of O end use suggests models in which the cis action of transposase and its choice of ends is determined by protein tracking along DNA molecules.
ANALYSIS OF THE DOSAGE COMPENSATION OF A SPECIFIC TRANSCRIPT IN DROSOPHILA MELANOGASTER
Authors: Breen Thomas R , Lucchesi John C 
Published: January 2021

ABSTRACT
The amount of steady-state level RNA complementary to the X-linked salivary gland secretion polypeptide gene Sgs-4 was measured in male and female third-instar larvae carrying one or two doses of a wild-type allele of the gene. RNA levels were found to be compensated in normal one-dose males and two-dose females and to be dosage-dependent within each sex. The presence of mutant alleles of male-less (mle) was found to reduce the level of Sgs-4 transcripts in males. These results support the contentions that dosage compensation is mediated by regulating the level of X-linked gene transcripts and that a product of the mle + gene is involved in this process.
TEMPORAL AND MICROGEOGRAPHIC VARIATION IN ALLOZYME FREQUENCIES IN A NATURAL POPULATION OF DROSOPHILA BUZZATII
Authors: Barker J S F , East P D , Weir B S 
Published: January 2021

ABSTRACT
Temporal variation in allozyme frequencies at six loci was studied by making monthly collections over 4 yr in one population of the cactophilic species Drosophila buzzatii. Ten sites were defined within the study locality, and for all temporal samples, separate collections were made at each of these sites. Population structure over microgeographic space and changes in population structure over time were analyzed using F-statistic estimators, and multivariate analyses of allele and genotype frequencies with environmental variables were carried out.—Allele frequencies showed significant variation over time, although there were no clear cyclical or seasonal patterns. A biplot analysis of allele frequencies over seasons within years and over years showed clear discrimination among years by alleles at four loci. During the 4 yr, three alleles showed directional changes which were associated with directional changes in environmental variables. Significant associations with one or more environmental variables were found for allele frequencies at every locus and for both expected and observed heterozygosities (except those for Est-1 and Est-2). Thus, variation in allele frequencies over time cannot be attributed solely to drift. Significant linkage disequilibria were detected among three loci (Est-2, Hex and Aldox), but there was no evidence for spatial or temporal patterns.—The F-statistic analyses showed significant differentiation among months within years for all loci, but the statistic used (coancestry) was heterogeneous among loci. Estimates of F (inbreeding) for all loci were significantly different from zero, with the loci in four groups, Adh-1 (negative), Pgm (small positive), Est-2 and Hex (intermediate) and Est-1 and Aldox (high positive). The correlation of genes within individuals within populations (f) for each locus in each month by site sample differed among loci, as did the patterns of change in f over time (seasons). Heterogeneity in the F-statistic estimates indicates that natural selection is directly or indirectly affecting allele and genotype frequencies at some loci. However, the F-statistic analyses showed essentially no microgeographic structure (i.e., among sites), although there was significant heterogeneity in allele frequencies among flies emerging from individual rots.—Thus, microspatial heterogeneity probably is most important at the level of individual rots, and coupled with habitat selection, it could be a major factor promoting diversifying selection and the maintenance of polymorphism. Resolution of the nature of this selection and of the apparent inbreeding detected at all loci except Adh-1 will require detailed study of the breeding structure of the population at the microhabitat level (individual rots) and of gene flow within the population.
ENZYME ACTIVITY IN EMS-INDUCED NULL MUTATIONS OF DUPLICATED GENES ENCODING PHOSPHOGLUCOSE ISOMERASES IN CLARKIA
Authors: Jones T W A , Pichersky E , Gottlieb L D 
Published: January 2021

ABSTRACT
The duplication of the nuclear gene encoding the cytosolic isozyme of phosphoglucose isomerase (PGI; EC 5.3.1.9) originated within Clarkia, a genus of annual plants native to California. Previous immunological studies showed that species with and without the duplication have the same levels of cytosolic PGI activity (relative to that of the plastid PGI isozyme), as well as similar levels of cytosolic PGI protein. In the present study, we characterized seven EMS-induced null activity mutations in both duplicate PGI genes. The mutations reduced PGI activity levels in direct proportion to the normal contribution of each gene. Homozygous mutants at Pgi-3 had 64% of wild-type activity, whereas those at Pgi-2 had only 36%. The effects of the mutations at the two loci were additive, as shown by further reductions in activity in certain progeny classes in F2 progenies between them. The homozygous double null mutant class was not recovered and is presumably lethal. All of the mutants appear to be CRM+. The results account for the previously observed differences in in vivo accumulation of the duplicate isozymes in numerous Clarkia species. The results further show that PGI activity is not directly regulated by metabolic factors and suggest that the reduced PGI levels in Clarkias with the duplication probably evolved by regulatory changes in transcription or translation. The study also demonstrates a novel method to evaluate whether a particular enzyme activity is essential.
GENEALOGY OF PRINCIPAL STRAINS OF THE YEAST GENETIC STOCK CENTER
Authors: Mortimer Robert K , Johnston John R 
Published: January 2021

ABSTRACT
We have constructed a genealogy of strain S288C, from which many of the mutant and segregant strains currently used in studies on the genetics and molecular biology of Saccharomyces cerevisiae have been derived. We have determined that its six progenitor strains were EM93, EM126, NRRL YB-210 and the three baking strains Yeast Foam, FLD and LK. We have estimated that approximately 88% of the gene pool of S288C is contributed by strain EM93. The principal ancestral genotypes were those of segregant strains EM93-1C and EM93-3B, initially distributed by C. C. Lindegren to several laboratories. We have analyzed an isolate of a lyophilized culture of strain EM93 and determined its genotype as MAT a/MAT? SUC2/SUC2 GAL2/gal2 MAL/MAL mel/mel CUP1/cup1 FLO1/flo1. Strain EM93 is therefore the probable origin of genes SUC2, gal2, CUP1 and flo1 of S288C. We give details of the current availability of several of the progenitor strains and propose that this genealogy should be of assistance in elucidating the origins of several types of genetic and molecular heterogeneities in Saccharomyces.
A VISIBLE ALLELE OF THE MUSCLE GENE sup-10 X OF C. ELEGANS
Authors: Greenwald Iva , Horvitz H Robert 
Published: January 2021

ABSTRACT
In this paper, we extend our previous analyses of a set of genes in Caenorhabditis elegans that are involved in muscle structure and function: unc-93 III, sup-9 II, sup-10 X and sup-11 I. We describe an unusual, visible allele of sup-10, examine how this allele interacts genetically with mutations in other genes of this set and propose that the wild-type products of the unc-93 and sup-10 loci may be components of a protein complex. We also describe a new gene of this set, sup-18 III, and the interaction of sup-18 alleles with mutations in the other genes.
MAIZE MITOCHONDRIAL PLASMID S-1 SEQUENCES SHARE HOMOLOGY WITH CHLOROPLAST GENE psbA
Authors: Sederoff Ronald R , Ronald Pamela , Bedinger Patricia , Rivin Carol , Walbot Virginia , Bland Molly , Levings C S 
Published: January 2021

ABSTRACT
The linear, 6397-base pair (bp), mitochondrial S-1 DNA molecule from maize contains a 420-bp segment that is homologous with the chloroplast gene (psbA) that codes for the quinone binding protein of photosystem II. This is the first report of a chloroplast sequence in a naturally occurring viral-like or plasmid DNA. The complete sequence of the S-1 chloroplast segment has been compared with homologous regions of six different chloroplast genes. The S-1 segment has diverged from the other genes both by length mutation and base substitution. Several of the length mutations are exact adjacent tandem duplications of 4 and 5 bp similar to "footprints" left after excision of transposable elements in maize nuclear DNA.