bluuebunny/crossref_metadata_2025_split huggingface dataset:
IMMUNOGENETIC POLYMORPHISM OF LIPOPROTEINS IN SWINE: GENETIC, IMMUNOLOGICAL AND PHYSIOCHEMICAL CHARACTERIZATION OF THE TWO ALLOTYPES LPR1 AND LPR2
Authors: Rapacz Jan , Hasler-Rapacz Judith , Kuo W H 
Published: January 2021

ABSTRACT
Results of immunogenetic, immunochemical and physicochemical investigations on two serum allotypes of swine are reported. The allotypes, designated Lpr1 and Lpr2, have been identified by specific alloprecipitins in agar gel. Genetic studies indicate that the allotypes are specified by two codominant autosomal allelic genes, Lpr 1 and Lpr 2. All pigs 3 months of age or older were classified as belonging to one of three phenotypes, Lpr1, Lpr2 or Lpr1,2, each corresponding to one of three genotypes Lpr 1/1, Lpr 2/2 or Lpr ½, respectively. The Lpr 1 gene was absent or was found at low frequency in the breeds tested. The allotypes were found to occur in two physicochemical forms; in association with chylomicrons and very low density lipoproteins (VLDL) and, primarily, as a Lpr multimer free of the major lipoproteins showing very high density (VHD), d &gt; 1.21 g/ml, and MW ± 190,000. Gel-electrophoretic mobility for VHD-Lpr is different for each of the three Lpr genotypes residing in γ-fast and β-slow regions, but is identical for VLD-Lpr in which Lpr was found complexed with apo-B, migrating as VLDL in the α-2 slow (pre-β) region. Serum levels of Lpr varied during the lifetime and between individuals and, especially, between sera of homozygous pigs being higher in Lpr 1/1 than Lpr 2/2. A linear relationship for Lpr1 and an atypical, inverse relationship for Lpr2 have been observed between the gene dosage, heterozygous vs. homozygous, and the Lpr serum level.
A REHABILITATION OF THE GENETIC MAP OF THE 84B-D REGION IN DROSOPHILA MELANOGASTER
Authors: Cavener Douglas R , Otteson Deborah C , Kaufman Thomas C 
Published: January 2021

ABSTRACT
A reanalysis of the 84B3 to 84B3,5 region of the polytene chromosomes of Drosophila melanogaster has led to the identification and localization of 16 genes. These genes include 11 vital loci, four genes exhibiting nonlethal visible mutant phenotypes and one gene encoding a nonessential enzyme. The identity of the gene products of two of the vital genes has been determined to be α-tubulin and glucose dehydrogenase (Gld). Three newly identified genes, sticking (stk), half out (hat) and trapped (ted), as well as Gld are required for eclosion. Among the nonessential genes are roughened eye (roe) and ruffed eye (rue), which affect eye texture. The roe phenotype is greatly enhanced by deletions that simultaneously remove roe and an unidentified locus in 84E. Mutations in another nonessential gene, rotund (rn), are characterized by pattern deletions of most adult appendages.
SEX DETERMINATION IN THE NEMATODE C. ELEGANS: ANALYSIS OF tra-3 SUPPRESSORS AND CHARACTERIZATION OF fem GENES
Authors: Hodgkin Jonathan 
Published: January 2021

ABSTRACT
Mutations of the gene tra-3 result in partial masculinization of XX animals of C. elegans, which are normally hermaphrodites (males are XO). A total of 43 tra-3 revertants (one intragenic, 42 extragenic) have been isolated and analyzed, in the hope of identifying new sex-determination loci. Most (38) of the extragenic suppressors cause partial or complete feminization of XX and XO animals; the remaining four are weak suppressors. The feminizing suppressors are mostly alleles of known sex-determining genes: tra-1 (11 dominant alleles), tra-2 (one dominant allele), fem-1 (four alleles) and fem-2 (four alleles), but 18 are alleles of a new gene, fem-3. Additional alleles have been isolated for the fem-2 and fem-3 genes, as well as fem-3 deficiencies. Mutations in fem-3 resemble alleles of fem-1 (previously characterized): putative null alleles result in complete feminization of XX and XO animals, transforming them into fertile females. Severe alleles of fem-2 also cause complete feminization of XX animals at all temperatures, but feminization of fem-2 XO animals is temperature-sensitive: complete at 25°, incomplete at 20°. As with fem-1, severe mutations of fem-2 and fem-3 are wholly epistatic to masculinizing alleles of tra-2 and tra-3, and epistatic to tra-1 masculinizing alleles in the germline, but not in the soma. All three fem genes are essential for male development and appear to have a dual role in promoting spermatogenesis and repressing tra-1 activity. All three fem genes exhibit strong maternal effects; the maternal contribution of fem gene products may be inactivated in XX animals by a posttranscriptional mechanism. Maternal contributions of wild-type fem-3 product are necessary for normal XO male development and XX hermaphrodite (as opposed to female) development.
THE CUTICLE PROTEINS OF DROSOPHILA MELANOGASTER: GENETIC LOCALIZATION OF A SECOND CLUSTER OF THIRD-INSTAR GENES
Authors: Chihara Carol J , Kimbrell Deborah A 
Published: January 2021

ABSTRACT
Five third-instar larval cuticle protein genes are placed on the left arm of the third chromosome. For these five genes, 12 variants and two induced mutants are described. All the naturally occurring variants are codominant. One EMS-induced mutant is characterized by the codominant appearance of a new protein, and a second by a recessive mutation that codes for a modifier of third-instar larval cuticle protein 5 (L3CP-5). All but the putative modifier gene map to within less than 0.3 map units of each other on the left arm of the third chromosome at approximately 11. We propose that these genes constitute a cluster of third-instar cuticle protein genes. The induced recessive mutant maps outside of the cluster to a region also on the left arm of the third chromosome. The proteins and their genes should prove useful for both developmental and evolutionary studies.
ALLOZYME SEGREGATION RATIOS IN THE INTERSPECIFIC CROSS CUCURBITA MAXIMA x C. ECUADORENSIS SUGGEST THAT HYBRID BREAKDOWN IS NOT CAUSED BY MINOR ALTERATIONS IN CHROMOSOME STRUCTURE
Authors: Weeden N F , Robinson R W 
Published: January 2021

ABSTRACT
The parentals of the interspecific cross Cucurbita maxima ×C. ecuadorensis had different isozyme phenotypes for 12 enzyme systems. Characterization of the systems demonstrated that the expression and intracellular distribution of the isozymes were similar to those in other plant taxa; however, a considerable number of duplicate loci were identified, indicative of a polyploid ancestry for Cucurbita. Genetic analysis provided evidence for 20 loci segregating in F2 and backcross populations. Five linkage groups were identified, consisting of the loci Aat-mb - - Mdh-m2; Gal-1 - - Gal-2; Aat-p2 - - Gpi-c2; Acp-1 - - Pgm-c2 - - Pgm-p; and Est-1 - - Tpi-c2. Significant deviations from Mendelian segregation ratios were observed in 14% of the data sets for individual loci. However, these instances were scattered among the loci, no single locus consistently displaying skewed ratios. Recombination frequencies between linked loci were similar to those observed in intraspecific crosses, and the ratio of heterozygous to homozygous genotypes in backcross populations was very close to one. These results suggest that small differences in chromosome structure were not the major cause of the loss of fertility observed in F2 and backcross populations.
MAGNIFICATION OF THE RIBOSOMAL GENES IN FEMALE DROSOPHILA MELANOGASTER
Authors: Komma Donald J , Endow Sharyn A 
Published: January 2021

ABSTRACT
The genetically induced increase in the number of 18S + 28S ribosomal genes known as magnification has been reported to occur in male Drososphila but has not previously been observed in females. We now report that bobbed magnified (bbm) is recovered in progeny of female Drosophila carrying three different X bobbed (Xbb) chromosomes and the helper (see PDF) chromosome, which is a derivative of the Ybb- chromosome. Using different combinations of bb or bb+ X and Y chromosomes, we show that magnification in females requires both a deficiency in ribosomal genes and the presence of a Y chromosome: X/X females that are rDNA-deficient but do not carry a Y chromosome do not produce bbm; similarly, X/X/Y females that carry a Y chromosome but are not rDNA-deficient do not produce bbm. Bobbed magnified is only recovered from rDNA-deficient (see PDF), X/X/Y or (see PDF) females. We have also found that females carrying a ring Xbb chromosome together with the (see PDF) chromosome do not produce bbm, indicating that ring X chromosomes are inhibited to magnify in females as in males. We postulate that the requirement for a Y chromosome is due to sequences on the Y chromosome that regulate or encode factor(s) required for magnification, or, alternatively, affect pairing of the ribosomal genes.—These studies demonstrate that magnification is not limited to males but also occurs in females. Magnification in females is induced by rDNA-deficient conditions and the presence of a Y chromosome, and probably occurs by a mechanism similar to that in males.
THE GENETIC FACTORS ALTERED IN HOMOZYGOUS abo STOCKS OF DROSOPHILA MELANOGASTER
Authors: Sullivan William , Pimpinelli Sergio 
Published: January 2021

ABSTRACT
Females homozygous for the maternal-effect mutation abo (2-44.0) produce a large fraction of eggs which arrest during embryogenesis. Increasing doses of defined heterochromatic regions inherited by offspring of abo mothers from their fathers function zygotically to bring about a partial rescue of the abo-induced embryonic lethality. Another property of the abo mutation is that the severity of the maternal effect decreases when an abo stock is maintained in homozygous condition for a number of generations. Here, we show that the factors which change in homozygous abo stocks to result in the decrease in maternally induced embryonic lethality, act zygotically, dominantly and additively. More importantly, we show that the X and second chromosomes, but not the Y and third chromosomes, derived from homozygous abo stocks are, when inherited from males, more effective in promoting zygotic rescue of the abo-induced lethality than are the equivalent chromosomes derived from an abo stock maintained in heterozygous condition. The chromosomal locations of the factors altered in the homozygous stock, as well as their behavior, strongly suggest that the same heterochromatic elements that are responsible for rescuing embryos from the abo-induced maternal effect are altered in homozygous abo flies in such a way that the maternal effect itself is less severe.
THE INTERACTION OF GENETIC AND ENVIRONMENTAL FACTORS IN THE CONTROL OF AMYLASE GENE EXPRESSION IN DROSOPHILA MELANOGASTER
Authors: Benkel Bernhard F , Hickey Donal A 
Published: January 2021

ABSTRACT
A number of previous studies have established that amylase activity can vary between Drosophila strains which are maintained under identical laboratory conditions. In addition, we have recently shown that all strains examined so far are subject to glucose repression of amylase activity. In this study, we show that the degree of glucose repression can vary between strains. Moreover, the glucose repression effect is much more pronounced in larvae than in adult flies. Our results lead to the conclusion that the strain-specific differences in activity and the dietary effects are not independent phenomena. These results have implications for the interpretation of many studies on amylase activity variation, including those experiments which have been designed to link amylase activity variations with fitness differences in nature. A question that naturally arises concerns the molecular basis for these strain-specific variations in the degree of glucose repression of this eukaryotic gene.
SEVERAL GALACTOSYLTRANSFERASE ACTIVITIES ARE ASSOCIATED WITH MOUSE CHROMOSOME 17
Authors: Furukawa Kiyoshi , Roth Stephen , Sawicki Janet 
Published: January 2021

ABSTRACT
Indirect evidence suggests that some major histocompatibility complex (MHC) proteins are glycosyltransferases. No sequence or mapping information is available for transferases, although ganglioside variations in mice are linked to the H-2 complex on chromosome 17, and one galactosyltransferase activity on mouse sperm varies with T/t complex genotypes, also on chromosome 17. In the present experiments, diploid and trisomy 17 mouse embryos were assayed for four different galactosyltransferase activities. The same preparations were assayed for isocitrate dehydrogenase (Id-1, chromosome 1) and glyoxalase-1 (Glo-1, chromosome 17). Galactosyltransferase specific activities in trisomy 17 embryos are almost 1.5 times higher than in diploid embryos. The correlation between galactosyltransferase activities and chromosome 17 dosage indicates that the structural or regulatory gene for these enzymes are located on chromosome 17.
Sexual Hyperactivity and Reduced Longevity of dunce Females of Drosophila melanogaster
Authors: Bellen Hugo J , Kiger John A 
Published: January 2021

ABSTRACT
The dunce gene of Drosophila melanogaster codes for a cyclic adenosine-3',5'-monophosphate-specific phosphodiesterase. Mutations of dunce alter or abolish the activity of this enzyme, produce elevated cAMP levels, cause recessive female sterility, and produce learning deficiencies in both sexes. Aberrant male sexual behavior has also been associated with the memory defects of dunce mutants. Here we show that the longevity of dunce mutant females, homozygous for null-enzyme alleles, is reduced by 50% in the presence of males compared to control dunce females kept without males. Mutant dunce females mate on average every 14 hours whereas wild type revertants of dunce, and Canton-S females, mate every 22-24 hr. We propose a cause-effect relationship between mating and reduced longevity. Pheromones or peptides transferred during mating may activate adenylate cyclase and create an increase in cAMP levels that cannot be damped in dunce females. This increase may affect basic physiological functions and lead to reduced longevity
Patterns of Somatic Mutations in Immunoglobulin Variable Genes
Authors: Golding G Brian , Gearhart Patricia J , Glickman Barry W 
Published: January 2021

ABSTRACT
The mechanism responsible for somatic mutation in the variable genes of antibodies is unknown and may differ from previously described mechanisms that produce mutation in DNA. We have analyzed 421 somatic mutations from the rearranged immunoglobulin variable genes of mice to determine (1) if the nucleotide substitutions differ from those generated during meiosis and (2) if the presence of nearby direct and inverted repeated sequences could template mutations around the variable gene. The results reveal a difference in the pattern of substitutions obtained from somatic mutations vs. meiotic mutations. An increased frequency of T:A to C:G transitions and a decreased frequency of mutations involving a G in the somatic mutants compared to the meiotic mutants is indicated. This suggests that the mutational processes responsible for somatic mutation in antibody genes differs from that responsible for mutation during meiosis. An analysis of the local DNA sequences revealed many direct repeats and palindromic sequences that were capable of templating some of the known mutations. Although additional factors may be involved in targeting mutations to the variable gene, mistemplating by nearby repeats may provide a mechanism for the enhancement of somatic mutation.
Molecular Nature of Spontaneous Mutations in Mouse Lactate Dehydrogenase-A Processed Pseudogenes
Authors: Fukasawa Kayoko M , Tanimura Masako , Sakai Ikuya , Sharief Farida S , Chung Fu-Zon , Li Steven S-L 
Published: January 2021

ABSTRACT
The presence of at least ten mouse LDH-A pseudogenes was demonstrated in the genomic blot analysis, and four different processed pseudogenes have thus far been isolated and characterized. In this report, the nucleotide sequences of two different mouse lactate dehydrogenase-A processed pseudogenes, M11 and M14, were determined and compared with the protein-coding sequences of the mouse and rat LDH-A functional genes. In the pseudogene M11, the sequence of 64 nucleotides from codon no. 257 to 278 was tandemly duplicated. In the pseudogene M14, the sequence of 22 nucleotides from codon no. 68 to 75 was replaced by an inserted repetitive sequence of 242 nucleotides homologous to a mouse truncated R element. The pattern of nucleotide substitutions accumulated in mouse LDH-A pseudogenes M11 and M14, as well as that of pseudogene M10 identified previously, was analyzed, and the substitution frequencies of the C or G at the CG dinucleotide were found to be high.
Metabolic Flux and Fitness
Authors: Dykhuizen Daniel E , Dean Antony M , Hartl Daniel L 
Published: January 2021

ABSTRACT
Studies of Escherichia coli under competition for lactose in chemostat cultures have been used to determine the selective effects of variation in the level of the β-galactoside permease and the β-galactosidase enzyme. The results determine the adaptive topography of these gene products relative to growth in limiting lactose and enable predictions concerning the selective effects of genetic variants found in natural populations. In the terms of metabolic control theory, the β-galactosidase enzyme at wild-type-induced levels has a small control coefficient with respect to fitness (C = 0.018), and hence genetic variants resulting in minor changes in enzyme activity have disproportionately small effects on fitness. However, the apparent control coefficient of the β-galactoside permease at wild-type-induced levels is large (C = 0.551), and hence even minor changes in activity affect fitness. Therefore, we predict that genetic polymorphisms in the lacZ gene are subject to less effective selection in natural populations than are those in the lacY gene. The β-galactoside permease is also less efficient than might be expected, and possible forces resulting in selection for an intermediate optimum level of permease activity are considered. The selective forces that maintain the lactose operon in a regulated state in natural populations are also discussed.
Mutations Causing Constitutive Invertase Synthesis in Yeast: Genetic Interactions with snf Mutations
Authors: Neigeborn Lenore , Carlson Marian 
Published: January 2021

ABSTRACT
We have selected 210 mutants able to grow on sucrose in the presence of 2-deoxyglucose. We identified recessive mutations in three major complementation groups that cause constitutive (glucose-insensitive) secreted invertase synthesis. Two groups comprise alleles of the previously identified HXK2 and REG1 genes, and the third group was designated cid1 (constitutive invertase derepression). The effect of cid1 on SUC2 expression is mediated by the SUC2 upstream regulatory region, as judged by the constitutive expression of a SUC2-LEU2-lacZ fusion in which the LEU2 promoter is under control of SUC2 upstream sequences. A cid1 mutation also causes glucose-insensitive expression of maltase. The previously isolated constitutive mutation ssn6 is epistatic to cid1, reg1 and hxk2 for very high level constitutive invertase expression. Mutations in SNF genes that prevent derepression of invertase are epistatic to cid1, reg1 and hxk2; we have previously shown that ssn6 has different epistasis relationships with snf mutations. The constitutive mutation tup1 was found to resemble ssn6 in its genetic interactions with snf mutations. These findings suggest that CID1, REG1 and HXK2 are functionally distinct from SSN6 and TUP1.
Construction of an Unstable Ring-X Chromosome Bearing the Autosomal Dopa Decarboxylase Gene in Drosophila melanogaster and Analysis of Ddc Mosaics
Authors: Gailey Donald A , Bordne Deborah L , Vallés Ana Maria , Hall Jeffrey C , White Kalpana 
Published: January 2021

ABSTRACT
An unstable Ring-X chromosome, Ddc +- Ring-X carrying a cloned Dopa decarboxylase (Ddc) encoding segment was constructed. The construction involved a double recombination event between the unstable Ring-X, R(1)wvC and a Rod-X chromosome which contained a P-element mediated Ddc + insert. The resulting Ddc +-Ring-X chromosome behaves similarly to the parent chromosome with respect to somatic instability. The Ddc +-Ring-X chromosome was used to generate Ddc mosaics. Analyses of Ddc mosaics revealed that while there was no absolute requirement for the Ddc + expression in either the epidermis or the nervous system, very large mutant clones did affect the viability of the mosaic.
A Comprehensive Study of Genic Variation in Natural Populations of Drosophila melanogaster. I. Estimates of Gene Flow from Rare Alleles
Authors: Singh Rama S , Rhomberg Lorenz R 
Published: January 2021

ABSTRACT
In order to assess the evolutionary significance of molecular variation in natural populations of Drosophila melanogaster, we have started a comprehensive genetic variation study program employing a relatively large number of gene-protein loci and an array of populations obtained from various geographic locations throughout the world. In this first report we provide estimates of gene flow based on the spatial distributions of rare alleles at 117 gene loci in 15 worldwide populations of D. melanogaster . Estimates of Nm (number of migrants exchanged per generation among populations) range from 1.09 in East-Asian populations (Taiwan, Vietnam and Australia) to 2.66 in West-Coast populations of North America. These estimates, among geographic populations separated by hundreds or even thousands of miles, suggest that gene flow among neighboring populations of D. melanogaster is quite extensive. This means that, for selectively neutral genes, we should expect little differentiation among neighboring populations. A survey of eight West-Coast populations of D. melanogaster (geographically comparable to Drosophila pseudoobscura) showed that in spite of extensive gene flow, populations of D. melanogaster show much more geographic differentiation than comparable populations of D. pseudoobscura. From this we conclude that migration in combination with natural selection rather than migration alone is responsible for the geographic uniformity of molecular polymorphisms in D. pseudoobscura.
Genetic Evidence of Mutator-Induced Deletions in the Short Arm of Chromosome 9 of Maize
Authors: Robertson Donald S , Stinard Philip S 
Published: January 2021

ABSTRACT
Evidence is presented that at least 12 of the Mu-induced yg2 mutants found in an extensive mutation analysis of this locus are the result of deletions in the region of the yg2 locus on the short arm of chromosome 9. Twelve of these putative deletions were characterized genetically, and in every instance, they were confirmed to be deletions involving chromosomal segments that include the yg2 and wd loci as well as additional portions of the short arm of chromosome 9.
Allosuppressors that Enhance the Efficiency of Omnipotent Suppressors in Saccharomyces cerevisiae
Authors: Song Jae Mahn , Liebman Susan W 
Published: January 2021

ABSTRACT
Two recessive Mendelian-allosuppressors have been isolated and have been shown to enhance the efficiency of omnipotent suppressors thought to be translational ambiguity mutations. These allosuppressors are unlinked to each other or to the omnipotent suppressors on which they act. They also increase the efficiency of the serine-inserting UAA-suppressor, SUP16 . One allosuppressor is allelic or tightly linked to the previously isolated sal2. Another allosuppressor, called sal6, represents a new locus, unlinked to the previously isolated sal1-sal5 that enhance the efficiency of the UAA-suppressors. When present singly in the absence of suppressors or other modifiers the sal2 and sal6 mutations do not have suppressor activity. However, when sal2 and sal6 are combined together in a haploid cell they do suppress weakly. In addition sal2 becomes a weak suppressor in the presence of the [η+] modifying factor.