bluuebunny/crossref_metadata_2025_split huggingface dataset:
ON THE DEVELOPMENT OF ECTOPIC EYES IN DROSOPHILA MELANOGASTER PRODUCED BY THE MUTATION EXTRA EYE (EE)
Authors: Baker William K , Marcey David J , McElwain M Catharine 
Published: January 2021

ABSTRACT
The mutation ee often produces an ectopic eye on the vertex that is a mirror image partial duplication of the normal eye on the ipsilateral side of the head. The pattern of the duplication and a clonal analysis by mitotic recombination indicate that the duplications are of dorsal eye and orbital structures. Large ectopic eyes (more than 100 ommatidia) and their surrounding bristles may be produced without cuticular deficiencies. The penetrance of ee is temperature dependent with penetrance higher (72%) at 25° and 29° than at 19° (43%). Temperature shift experiments show two temperature-sensitive periods: one at midembryogenesis, the other at mid-first larval instar. Microscopic examination of ee late-second and third instar imaginal cephalic discs show no indication of growth of the extra tissue needed to produce the duplication until after mid-third instar. This was confirmed by cell counts of ee and wild-type discs. There is no evidence of differential cell death in the two types of discs at this stage, although much earlier cell death is postulated. Tests for cell autonomy of the mutation by the production of morphogenetic clones suggest nonautonomy. Formation of pattern duplications by mutant genes is discussed in terms of cell death that eliminates whole developmental compartments, restricted cell death that occurs within a compartment, extensive cell death within a compartment and proliferative growth unassociated with cell lethality.
GENETIC ANALYSIS OF MUTANTS WITH A REDUCED Ca2+-DEPENDENT K+ CURRENT IN PARAMECIUM TETRAURELIA
Authors: Hinrichsen Robert D , Amberger Ed , Saimi Yoshiro , Burgess-Cassler Anthony , Kung Ching 
Published: January 2021

ABSTRACT
Two mutants of Paramecium tetraurelia with greatly reduced Ca2+-dependent K+ currents have been isolated and genetically analyzed. These mutants, designated pantophobiac, give much stronger behavioral responses to all stimuli than do wild-type cells. Under voltage clamp, the Ca2+-dependent K+ current is almost completely eliminated in these mutants, whereas the Ca2+ current is normal. The two mutants, pntA and pntB, are recessive and unlinked to each other. pntA is not allelic to several other ion-channel mutants of P. tetraurelia. The microinjection of a high-speed supernatant fraction of wild-type cytoplasm into either pantophobiac mutant caused a temporary restoration to the wild-type phenotype.
GENETIC ANALYSIS OF THE HAIRY LOCUS IN DROSOPHILA MELANOGASTER
Authors: Ingham P W , Pinchin S M , Howard K R , Ish-Horowicz D 
Published: January 2021

ABSTRACT
Mutations of the hairy locus in Drosophila may affect both adult chaeta differentiation and embryonic segmentation. In an effort to understand this phenotypic complexity, we have analyzed 30 mutant alleles of the locus. We find that the alleles fall into four groups according to their complementation properties, suggesting a structurally complex locus in which two distinct functions share a common coding region.
A DETAILED DEVELOPMENTAL AND STRUCTURAL STUDY OF THE TRANSCRIPTIONAL EFFECTS OF INSERTION OF THE COPIA TRANSPOSON INTO THE WHITE LOCUS OF DROSOPHILA MELANOGASTER
Authors: Zachar Zuzana , Davison Dan , Garza Dan , Bingham Paul M 
Published: January 2021

ABSTRACT
The copia insertion responsible for the wamutation is 3' to the white promotor and in the same transcriptional orientation as white. First, we have analyzed the effects of the wa copia insertion on levels of polyadenylated white transcripts and find large, developmentally programmed effects. Second, we have isolated and sequenced an LTR-excision event involving the copia insertion at wa. This represents the first documented case of an LTR-excision event in Drosophila. This single copia LTR has developmentally programmed effects on white transcript levels qualitatively similar to the intact copia element. Third, we have characterized the structures of white transcripts from wa. We find polyadenylated white transcripts apparently having 3' termini in or near the 3' LTR of the wa copia insertion, as has been reported in limited studies of wa transcription in adults by others. These earlier studies also revealed wa transcripts apparently corresponding to polyadenylated terminus formation in the 5' LTR of the copia transposon; however, our more detailed studies reveal that these transcripts probably have other origins and that little, if any, polyadenylated terminus formation for white transcripts occurs in the 5' LTR of the wa copia insertion. Moreover, we find no polyadenylated terminus formation for white transcripts occurring in the single LTR of the wa LTR-excision product. Fourth, we find that each of three mutant alleles at su(wa) produces elevated levels of several classes of RNAs apparently corresponding to transcriptional readthrough of the wa copia transposon. Elevated levels of one presumptive readthrough transcript were observed previously in one su(wa)1 mutant strain. Fifth, we have confirmed the existence of a transcript initiated in the 3' LTR of the wa copia insertion and find the levels of this transcript to be strongly influenced by developmental stage and genetic background. Lastly, we have analyzed white transcripts produced by the whd 81b11 allele, which carries an insertion of copia in the opposite transcriptional orientation and in a different position than the wa copia insertion. In contrast to the wa copia insertion allele, the whd 81b11 allele produces polyadenylated white transcript levels very similar to the w + case at the stages examined. Moreover, the whd 81b11 copia element apparently produced polyadenylated terminus formation in white transcripts and we observe no effect of the allelic state of su(wa) on apparent readthrough of this stop site. We discuss some possible implications of our results for the properties of retrotransposons as developmentally complex insertional mutagens and for the functional organization of the copia transcription unit.
GENETICS OF MANDIBLE FORM IN THE MOUSE
Authors: Atchley William R , Plummer A Alison , Riska Bruce 
Published: January 2021

ABSTRACT
The underlying determination of phenotypic variability and covariability is described for 14 traits that define the morphological size and shape of the mature mouse mandible. Variability is partitioned into components due to direct additive and dominance genetic effects, indirect maternal additive genetic effects, genetic covariance between direct additive and indirect maternal additive effects and common and residual environmental effects. Multivariate analyses of the dimensionality of genetic variability indicate several complex and independent genetic components underlie the morphological form of the mandible. The multidimensional nature of the genetic components suggests a complex picture with regard to the consequences of selection on mandibular form.
DEVELOPMENTAL GENETICS OF MUTANTS THAT SPECIFY KNOTTED LEAVES IN MAIZE
Authors: Freeling Michael , Hake Sarah 
Published: January 2021

ABSTRACT
Of seven dominant knotted-leaf mutants tested, six mapped at or near Kn1 on the long arm of chromosome 1, and one was not linked to Kn1. Comparisons of phenotypes among these mutants allowed us to focus on a systematic abnormality: the parenchyma cells associated with lateral veins do not fully differentiate into bundle sheath, mesophyll or upper sclerenchyma. The more dramatic expression of Kn1 mutants–knots, ligule alterations and twisting–is sporadic and dependent on the time when the mutant acts in leaf primordium development. Using lw to mark leaf sectors that lose Kn1 following X-irradiation, we show that the knotted-leaf phenotype encoded by chromosome 1L is autonomous. Analysis of sectors lacking a particular Kn1 gene (Kn1-N2) suggests that Kn1 itself, rather than a linked modifier gene, is autonomous in the leaf primordium. Aneuploid studies using various translocations involving 1L and marked by Adh1 allozymes are compared. The Kn1 mutant appears to encode a "new" function or a considerable overproduction of an extant product in the leaf. Kn1/- 1L hypoploids either express knotted poorly or not at all; transvection is ruled out, but the cause for this modification of Kn1 expression is not yet known.—Our working hypothesis is that Kn1 mutants permit the expression of a product that is usually not produced in leaf primordial cells. We suggest that this product interferes with the early cell-type commitments of cells near lateral veins. Thus, relatively uncommitted cells are present in more mature blades, where they may divide unexpectedly into knots or may induce bits of ligule.
GENE ACTIONS INVOLVED IN DETERMINING THE NUMBER OF OVARIOLES AND STERNITE CHAETAE IN FRESHLY COLLECTED STRAINS OF DROSOPHILA MELANOGASTER
Authors: Thomas-Orillard Michele , Jeune Bernard 
Published: January 2021

ABSTRACT
The nature of gene action involved in the mode of determination of two quantitative traits of Drosophila melanogaster, e.g., number of ovarioles and sternite chaetae, was studied in freshly captured strains and their crosses, using the biomodel built up by Cockerman and Weir. The results proved to be similar to those obtained with laboratory populations. The genome is by far the most important source of variation for the two traits. Extragenetic interactions are far more important in freshly captured stock than in flies which have already been propagated for several years in the laboratory. We can now interpret neutrality of a quantitative character as a state of equilibrium between medium and population. Since there are extragenetic interactions (type k) in the case of the neutral character, we could even think of possible future variations able to alter its mean value in such a way as to make it selective.
ESCHERICHIA COLI GENE INDUCTION BY ALKYLATION TREATMENT
Authors: Volkert Michael R , Nguyen Dinh C , Beard K Christopher 
Published: January 2021

ABSTRACT
Searches for alkylation-inducible (aid) genes of Escherichia coli have been conducted by screening random fusions of the Mu-dl(ApR lac) phage for fusions showing increased β-galactosidase activity after treatment with methylating agents, but not after treatments with UV-irradiation. In this report we describe gene fusions that are specifically induced by alkylation treatments. Nine new mutants are described, and their properties are compared with the five mutants described previously. The total of 14 fusion mutants map at five distinct genetic loci. They can be further subdivided on the basis of their induction by methyl methanesulfonate (MMS) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). alkA, aidB and aidD are induced by both agents and appear to be regulated by ada. Neither aidC nor aidI is regulated by ada. Moreover, since aidC is induced only by MNNG and aidI is induced only by MMS, these two genes are likely to be individually regulated. Thus, there appear to be at least three different regulatory mechanisms controlling aid genes.
PERSISTENCE OR RAPID GENERATION OF DNA LENGTH POLYMORPHISM AT THE ZETA-GLOBIN LOCUS OF HUMANS
Authors: Chapman Barbara S , Vincent Karen A , Wilson Allan C 
Published: January 2021

ABSTRACT
Extensive restriction mapping of 76 human genomic DNAs defines multiple sites of length and point mutation near the zeta-globin locus, which codes for an embryonic alpha-like globin chain. There are two major sites of DNA length variation: one in the intergenic region with three alleles and one in the first intron of the zeta 1 gene with at least four alleles. Our mapping establishes that the intronic polymorphism is associated with a tandem array of short, repeated sequences. The length alleles occur in each of four human populations sampled, suggesting an ancient origin with persistence of several length alleles, or rapid regeneration of these particular variants. Four polymorphic restriction sites were also found; the frequency of polymorphic sites is comparable to that found in the human beta-globin gene region. Analysis of haplotypes indicates either that multiple recombinations have occurred near the 5' end of the zeta 1 gene or that this region is prone to recurrent length mutation.
LOCALIZATION IN THE TOMATO GENOME OF DNA RESTRICTION FRAGMENTS CONTAINING SEQUENCES HOMOLOGOUS TO THE rRNA (45S), THE MAJOR CHLOROPHYLL a/b BINDING POLYPEPTIDE AND THE RIBULOSE BISPHOSPHATE CARBOXYLASE GENES
Authors: Vallejos C E , Tanksley S D , Bernatzky R 
Published: January 2021

ABSTRACT
DNA restriction fragments containing sequences homologous to the ribosomal RNA (45s), the major chlorophyll a/b binding polypeptide (CAB) and the small subunit of ribulose bisphosphate carboxylase (RBCS) genes have been localized and mapped in the tomato nuclear genome by linkage analysis. Ribosomal RNA genes map to a single locus, R45s, which resides in a terminal position on the short arm of chromosome 2 and corresponds to the Nucleolar Organizer Region. The size of the 45s repeating unit is estimated to be approximately 9 kb in Lycopersicon esculentum and 11 kb in Lycopersicon pennellii. Five loci were found to contain CAB sequences. Two of the loci, Cab-1 (chromosome 2) and Cab-3 (chromosome 8), together accounted for more than 80% of the hybridization signal. These loci contain more than one CAB structural gene. The other three loci, Cab-2 (chromosome 8), Cab-4 (chromosome 7) and Cab-5 (chromosome 12), each account for &lt;10% of the total signal and may contain only a single copy of the CAB structural sequence. Three loci were found to contain RBCS sequences. Rbcs-2 (chromosome 3) and Rbcs-3 (chromosome 2) were responsible for &gt;80% of the signal, with the remainder being associated with Rbcs-1 (chromosome 2). Rbcs-2 and Rbcs-3 may contain more than one copy of the gene.
NEGATIVE DOMINANT MUTATIONS OF THE uidR GENE IN ESCHERICHIA COLI: GENETIC PROOF FOR A COOPERATIVE REGULATION OF uidA EXPRESSION
Authors: Blanco Carlos , Ritzenthaler Paul , Mata-Gilsinger Mireille 
Published: January 2021

ABSTRACT
The uidA gene is the first gene involved in the hexuronide-hexuronate pathway in Escherichia coli K-12 and is under the dual control of the uidR and uxuR encoded repressors. Point mutations affecting the uidR regulatory gene were sought to investigate the regulation of uidA. When the uidR mutant allele was on a multicopy plasmid and the wild-type allele was on the chromosome, some of the mutant phenotypes were dominant to the wild-type phenotype, indicating that the active form of the UidR repressor is multimeric. We have demonstrated that expression of the mutant phenotype is dependent on gene dosage. The dominance of the uidR allele was also sensitive to the presence of the wild-type uxuR allele in the cell. This behavior probably results from UidR-UxuR repressor interactions. A mechanism is proposed: we suggest that the UidR and UxuR repressors interact after their binding to the operator site of uidA; the binding of one regulatory molecule may facilitate the binding of the other one in a cooperative process.
SEGREGATION ANALYSES AND GENE-CENTROMERE DISTANCES IN ZEBRAFISH
Authors: Streisinger George , Singer Fred , Walker Charline , Knauber Donna , Dower Nancy 
Published: January 2021

ABSTRACT
The gol-1, gol-2, alb-1 and spa-1 mutations affect pigment pattern in the zebrafish. We show here that these loci are unlinked to each other. In addition, gene-centromere distances were determined for these loci by analysis of halftetrads obtained by the inhibition of the second meiotic division. The fractions of tetratype (second-division segregation) tetrads range from 0.24 (spa-1) to 0.89 (gol-1). The observation of &gt;0.67 second-division segregation indicates that the zebrafish has high chiasma interference.
A GENETIC ANALYSIS OF PRIMARY PRODUCTS OF BACTERIOPHAGE LAMBDA RECOMBINATION
Authors: Huisman Olivier , Fox Maurice S 
Published: January 2021

ABSTRACT
Primary products of bacteriophage lambda recombination that display heterozygosity as a consequence of the presence of regions of heteroduplex DNA are rare in standard λ crosses. Phage manifesting heterozygosity at a given allele are evident when recombinants, emerging from a cross, are selected for an exchange in a neighboring interval. We show that the abundance of such heterozygotes can be increased 10- to 20-fold by selection on an E. coli indicator that is defective in methyl-directed mismatch repair (mutL). Thus, the activity of the methyl-directed mismatch repair system is, at least in part, responsible for the low frequency of detectably heterozygous phage emerging from a standard cross. In a mutL indicator, many primary products of recombination are replicated without the intervention of mismatch repair.—The products of a six-factor phage cross have been plated on a mutL indicator allowing visual detection of those phage products heterozygous for one of the allelic pairs, cI. By genetic analysis, we show that the heteroduplex regions of these primary products of recombination are on the average about 4 kb in length and can include as much as half of the lambda genome.
DNA REPAIR DEPENDENCE OF SOMATIC MUTAGENESIS OF TRANSPOSON-CAUSED WHITE ALLELES IN DROSOPHILA MELANOGASTER AFTER TREATMENT WITH ALKYLATING AGENTS
Authors: Fujikawa Kazuo , Kondo Sohei 
Published: January 2021

ABSTRACT
DNA repair-defective alleles of the mei-9, mei-41, mus-104 and mus-101 loci of Drosophila melanogaster were introduced into stocks bearing the UZ and SZ marker sets. Males with the UZ marker set, z 1 (zeste allele) and w +(TE) (genetically unstable white allele presumably caused by a transposable element), or the SZ marker set, z 1 and w +R (semistable white allele caused by partial duplication of the w + locus plus transposon insert), were exposed to EMS at the first instar. After emergence, adult males bearing red spots on lemon-yellow eyes were scored as flies with somatic reversions of w +(TE) or w +R. The relative mutabilities (relative values of reversion frequency at an equal EMS dose) of either w +(TE) or w +R in a repair-proficient strain and in mei-9, mei-41, mus-104 and mus-101 strains were 1:?1.2:0.3:0.3:0.7, despite the fact that w +(TE) reverted two to three times as frequently as w +R under both the repair-proficient and repair-deficient genetic conditions. Similarly, after treatment with MMS, MNNG and ENNG, w +(TE) was somatically more mutable in the mei-9 strain and less mutable in the mei-41 and mus-104 strains than in the repair-proficient strain. From these results, we propose that mutagenic lesions produced in DNA by treatment with these chemicals are converted to mutant DNA sequences via the error-prone repair mechanisms dependent on the products of the genes mei-41 + (mei-41 and mus-104 being alleles of the same locus) and mus-101 +, whereas they are eliminated by mei-9 +-dependent excision repair. In contrast to the approximately linear responses of induced reversions of w +(TE) with ENNG in the repair-proficient, mei-9, and mei-41 strains, seemingly there were dosage insensitive ranges for induced reversion with MNNG in the repair-proficient and mei-41 strains, but not for reversion in the mei-9 strain; w +(TE) in the mus-104 strain was virtually nonmutable with MNNG and ENNG. These results suggest that O 6-methylguanine (O 6MeG) produced in DNA with MNNG, but not O 6-ethylguanine produced with ENNG, is almost completely repaired in a low dose range by constitutive activity of DNA O 6MeG transmethylase. From the distribution of clone sizes of spontaneous revertant spots and other data, we propose that both w +(TE) and w +R have a similar tendency to spontaneously revert more frequently at early rather than at late developmental stages, probably reflecting a common property of their inserted transposons.
DEFICIENCY ANALYSIS OF THE TIP OF CHROMOSOME 3R IN DROSOPHILA MELANOGASTER
Authors: Kongsuwan Kritaya , Dellavalle Robert P , Merriam John R 
Published: January 2021

ABSTRACT
Region 98EF-100F in chromosome 3 is interesting for genetic analysis because it contains a number of genes of developmental importance. Although there are no preexisting simple deficiency stocks, this region is amenable to genetic manipulation using other types of rearrangements. In the present investigation we obtained deficiencies by combining the terminal deficiencies formed by segregation of Y;3 translocations with a series of duplications of the tip of 3R, both from Y;3 translocations with different breakpoints and from 3;1 duplications in which the 3R tip is carried as a second arm on the X chromosome. Analysis of such synthetic deficiencies reveals five haplo-abnormal loci in the 98A-100F interval. These include a haplolethal site, a newly described Minute and three previously reported Minute mutations. The newly discovered Minute has been designated M(3)99D and is localized cytologically to bands 99D1-9. The three previously reported Minute loci in the region have been localized more precisely: M(3)1 to bands 99B5-9, M(3)f to bands 99E4-F1 and M(3)g to region 100C-F. In addition, we have been able to obtain synthetic deficiencies uncovering all of the intervals from 99B5 to 100B. These deficiencies will be useful for future genetic and molecular analyses of the genes that map within the right tip of chromosome 3.
SELECTION AND BIASED GENE CONVERSION IN A MULTIGENE FAMILY: CONSEQUENCES OF INTERALLELIC BIAS AND THRESHOLD SELECTION
Authors: Walsh James Bruce 
Published: January 2021

ABSTRACT
In a previous paper, I investigated the interactions in a gene family of additive selection and biased gene conversion in a finite population when conversion events are rare. Here I extend my "weak-conversion limit" model by allowing biased interallelic conversion (conversion between alleles at the same locus) of arbitrary frequency and various threshold selection schemes for rare interlocus conversion events. I suggest that it is not unreasonable for gene families to experience threshold fitness functions, and show that certain types of thresholds can greatly constrain the rate at which advantageous alleles are fixed as compared to other fitness schemes, such as additive selection. It is also shown that the double sampling process operating on a gene family in a finite population (sampling over the number of genes in the gene family and over the number of individuals in the population) can have interesting consequences. For selectively neutral alleles that experience interallelic bias, the probability of fixation at each single locus may be essentially neutral, but the cumulative effects on the entire gene family of small departures from neutrality can be significant, especially if the gene family is large. Thus, in some situations, gene families can respond to directional forces that are weak in comparison to drift at single loci.