VIABILITY ESTIMATES FOR SIXTY TOMATO MUTANTS

1977 ◽  
Vol 19 (1) ◽  
pp. 31-38 ◽  
Author(s):  
L. Butler
Keyword(s):  
Chromosomal Rearrangement ◽  
Sudden Change ◽  
Lethal Gene ◽  
Chromosome 2 ◽  
Wild Type ◽  
First Case ◽  
Segregation Ratios ◽  
Uniform Background ◽  
Slow Growing ◽  
Types Of Change

Monogenic segregation data for 60 mutants show that for 42 of them the observed number was less than the expected and 25 of these 42 were significantly less. In many cases the discrepancy was too small to de detected in populations; of less than 500 plants. In no case was the mutant more viable than the wild type allele unless one accepts data for mutants H and o which appear to be cases of misclassification. The cause of the inviability was obvious in many cases where the mutant was slow growing (I, dil, tf), or poor germinating (ro, au, dpy), but in many cases the mutant wais as vigorous as the wild type. There were two types of change in viability, in the first case newly arisen mutants became more viable as the result of selection on different genetic backgrounds, in the second case there was a sudden change in viability because the mutant became associated in coupling phase with a lethal gene. The segregation ratios of genes at the proximal end of chromosome 2 are affected by the gametic eliminator (gt) whereas segregations in the central region, in the vicinity of aw, are affected by a chromosomal rearrangement. Genes at the distal end of chromosome 2 may have distorted ratios because of a lethal near the bip locus. The importance of uniform background and planned experiments is pointed out.

scholarly journals cot1: A Regulator of Arabidopsis Trichome Initiation

Genetics ◽  
1998 ◽  
Vol 149 (2) ◽  
pp. 565-577
Author(s):  
Daniel B Szymanski ◽  
Daniel A Klis ◽  
John C Larkin ◽  
M David Marks
Keyword(s):  
Cell Fate ◽  
Gene Dosage ◽  
Signal Transduction Pathway ◽  
Spatial Arrangement ◽  
Complex Signal ◽  
Chromosome 2 ◽  
Wild Type ◽  
Trichome Formation ◽  
In The Wild ◽  
Leaf Trichome

Abstract In Arabidopsis, the timing and spatial arrangement of trichome initiation is tightly regulated and requires the activity of the GLABROUS1 (GL1) gene. The COTYLEDON TRICHOME 1 (COT1) gene affects trichome initiation during late stages of leaf development and is described in this article. In the wild-type background, cot1 has no observable effect on trichome initiation. GL1 overexpression in wild-type plants leads to a modest number of ectopic trichomes and to a decrease in trichome number on the adaxial leaf surface. The cot1 mutation enhances GL1-overexpression-dependent ectopic trichome formation and also induces increased leaf trichome initiation. The expressivity of the cot1 phenotype is sensitive to cot1 and 35S::GL1 gene dosage, and the most severe phenotypes are observed when cot1 and 35S::GL1 are homozygous. The COT1 locus is located on chromosome 2 15.3 cM north of er. Analysis of the interaction between cot1, try, and 35S::GL1 suggests that COT1 is part of a complex signal transduction pathway that regulates GL1-dependent adoption of the trichome cell fate.

scholarly journals An unusual genomic position effect on Drosophila white gene expression: pairing dependence, interactions with zeste, and molecular analysis of revertants.

Genetics ◽  
1992 ◽  
Vol 130 (1) ◽  
pp. 125-138 ◽  
Author(s):  
T Hazelrigg ◽  
S Petersen
Keyword(s):  
Gene Expression ◽  
Regulatory Element ◽  
Position Effect ◽  
Insertion Site ◽  
White Gene ◽  
Chromosome 2 ◽  
Wild Type ◽  
Gene Copies ◽  
In Trans ◽  
In Cis

Abstract The white gene in the AR4-24 P[white,rosy] insertion on chromosome 2 has a novel expression pattern, in which it is repressed in the dorsal half of the eye. X-ray mutagenesis led to the isolation of six revertants mapping to chromosome 2, which are wild type in a zeste+ background, and three extreme derivatives, in which white gene expression is repressed in ventral regions of the eye as well. By Southern blot analyses the breakpoints of five of the revertants and one of the extreme derivatives were mapped in the flanking DNA bordering each side of the AR4-24 insertion. The revertants show some dorsal repression of white in the presence of z1, and by this criterion each is only a partial revertant. The extreme derivatives act not only in cis, but also in trans to repress expression of AR4-24 and its various derivatives. We provide evidence that these trans effects are proximity-dependent effects, possibly mediated by pairing of gene copies, as they do not extend to copies of the white gene located elsewhere in the genome. We show that one extreme derivative, E1, is a small deletion spanning the insertion site at the 5' end of the white gene, and propose that the distance between a negative regulatory element in the 5' flanking DNA and the white promoter influences the degree of the repression.

scholarly journals Genetic and molecular analysis of the proximal region of the mouse t-complex using new molecular probes and partial t-haplotypes.

Genetics ◽  
1990 ◽  
Vol 126 (4) ◽  
pp. 1103-1114 ◽  
Author(s):  
C A Howard ◽  
G R Gummere ◽  
M F Lyon ◽  
D Bennett ◽  
K Artzt
Keyword(s):  
Wild Mouse ◽  
Molecular Probes ◽  
Proximal Region ◽  
Chromosome 17 ◽  
Lethal Gene ◽  
Strong Linkage Disequilibrium ◽  
Wild Type ◽  
T Complex ◽  
Naturally Occurring ◽  
Normal Transmission

Abstract The t-complex is located on the proximal third of chromosome 17 in the house mouse. Naturally occurring variant forms of the t-complex, known as complete t-haplotypes, are found in wild mouse populations. The t-haplotypes contain at least four nonoverlapping inversions that suppress recombination with the wild-type chromosome, and lock into strong linkage disequilibrium loci affecting normal transmission of the chromosome, male gametogenesis and embryonic development. Partial t-haplotypes derived through rare recombination between t-haplotypes and wild-type homologs have been critical in the analysis of these properties. Utilizing two new DNA probes. Au3 and Au9, and several previously described probes, we have analyzed the genetic structure of several partial t-haplotypes that have arisen in our laboratory, as well as several wild-type chromosomes deleted for loci in this region. With this approach we have been able to further our understanding of the structural and dynamic characteristics of the proximal region of the t-complex. Specifically, we have localized the D17Tul locus as most proximal known in t-haplotypes, achieved a better structural analysis of the partial t-haplotype t6, and defined the structure and lethal gene content of partial t-haplotypes derived from the lethal tw73 haplotype.

scholarly journals A Natural Mutation Involving both Pathogenicity and Perithecium Formation in the Fusarium graminearum Species Complex

2016 ◽  
Vol 6 (12) ◽  
pp. 3883-3892 ◽  
Author(s):  
Haruhisha Suga ◽  
Koji Kageyama ◽  
Masafumi Shimizu ◽  
Misturo Hyakumachi
Keyword(s):  
Mutant Strain ◽  
Fusarium Graminearum ◽  
Type Strain ◽  
Species Complex ◽  
Wild Type Strain ◽  
Genetic Locus ◽  
Chromosome 2 ◽  
Wild Type ◽  
Head Blight ◽  
Fusarium Graminearum Species Complex

Abstract Members of the Fusarium graminearum species complex (Fg complex or FGSC) are the primary pathogens causing Fusarium head blight in wheat and barley worldwide. A natural pathogenicity mutant (strain 0225022) was found in a sample of the Fg complex collected in Japan. The mutant strain did not induce symptoms in wheat spikes beyond the point of inoculation, and did not form perithecia. No segregation of phenotypic deficiencies occurred in the progenies of a cross between the mutant and a fully pathogenic wild-type strain, which suggested that a single genetic locus controlled both traits. The locus was mapped to chromosome 2 by using sequence-tagged markers; and a deletion of ∼3 kb was detected in the mapped region of the mutant strain. The wild-type strain contains the FGSG_02810 gene, encoding a putative glycosylphosphatidylinositol anchor protein, in this region. The contribution of FGSG_02810 to pathogenicity and perithecium formation was confirmed by complementation in the mutant strain using gene transfer, and by gene disruption in the wild-type strain.

scholarly journals Low-Grade Fibromyxoid Sarcoma of the Lateral Skull Base: Presentation of Two Cases

2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
Evgenia Chetverikova ◽  
Priit Kasenõmm
Keyword(s):  
Malignant Tumour ◽  
Low Grade ◽  
Loss Of Consciousness ◽  
First Case ◽  
Clinical Presentations ◽  
Lateral Skull Base ◽  
Fibromyxoid Sarcoma ◽  
Gag Reflex ◽  
The Right ◽  
Slow Growing

Low-grade fibromyxoid sarcoma (LGFMS) is a rare slow-growing malignant tumour with a deceptively benign histologic appearance. Herein, we report two cases of LGFMS with variable clinical presentations. The first case was a 17-year-old female who referred to our department due to deaf ear on the right together with ipsilateral gag reflex impairment and globus sensation in the pharynx. The second case was a 35-year-old female with recurrent LGFMS, suffering from headaches, vertigo, and episodes of loss of consciousness. LGFMS of the temporal bone is a rare pathology, and to the best of our knowledge, no such cases have been reported before.

scholarly journals Microcell-mediated cotransfer of genes specifying methotrexate resistance, emetine sensitivity, and chromate sensitivity with Chinese hamster chromosome 2.

1981 ◽  
Vol 1 (4) ◽  
pp. 330-335 ◽  
Author(s):  
R Worton ◽  
C Duff ◽  
W Flintoff
Keyword(s):  
Karyotype Analysis ◽  
Marker Chromosome ◽  
Chinese Hamster ◽  
Chromosome 2 ◽  
Wild Type ◽  
Regional Localization ◽  
Methotrexate Resistance ◽  
Microcell Hybrids ◽  
Or Genes ◽  
Gene Transfer Technique

Many selectable mutants of somatic Chinese hamster cells have been described, but very few of the mutations have been mapped to specific chromosomes. We have utilized the microcell-mediated gene transfer technique to establish the location of three selectable genetic markers on chromosome 2 of Chinese hamster. Microcells were prepared from the methotrexate-resistant MtxRIII line of Flintoff et al. (Somatic Cell Genet. 2:245-261, 1976) and fused to wild-type CHO cells, and microcell hybrids (transferants) were selected in medium containing methotrexate. All transferants were karyotyped and found to contain a marker chromosome from the donor MtxRIII line. This marker chromosome, called 2p-, consisted of a chromosome 2 with a reduced short arm resulting from a reciprocal translocation between 2p and 5q. In experiments utilizing emetine-resistant (Emtr) or chromate-resistant (Chrr) recipient cells it was found that the emt+ and chr+ wild-type genes were cotransferred with the 2p- chromosomes. Karyotype analysis of several transferants with rearranged or broken 2p- markers allowed regional localization of the emt and chr loci to the proximal third of the long arm and localization of the gene or genes conferring methotrexate resistance to the short arm. These results confirm our earlier assignment of the emt and chr loci to chromosome 2 in Chinese hamster.

Antheridiogen concentration and spore size predict gametophyte size in Ceratopteris richardii

Botany ◽  
2012 ◽  
Vol 90 (3) ◽  
pp. 175-179 ◽  
Author(s):  
Mike Ganger ◽  
Tiffany Sturey
Keyword(s):  
Sex Determination ◽  
Environmental Sex Determination ◽  
Wild Type ◽  
Ceratopteris Richardii ◽  
Spore Size ◽  
Male Development ◽  
Homosporous Fern ◽  
Type C ◽  
Slow Growing ◽  
Genetic Mutants

In many plants females invest more in reproduction than males. In organisms that exhibit environmental sex determination, individuals in low-quality environments or who are slow growing are expected to develop into males. The gametophytes of Ceratopteris richardii Brongn., a homosporous fern, may develop as males or hermaphrodites. Hermaphrodites secrete a pheromone called antheridiogen that induces undifferentiated spores to develop as males. Given that induction is not 100% in the presence of antheridiogen, it is hypothesized that resources may alter C. richardii gender decisions. An experiment was undertaken to determine (i) whether spore size predicts gender, (ii) whether spore size predicts gametophyte size, (iii) whether antheridiogen negatively affects the growth of C. richardii, and (iv) whether wild-type C. richardii and him1 mutants (genetic mutants disposed to male development regardless of antheridiogen presence) behave similarly in their response to antheridiogen. Spore size was not predictive of gender but was positively related to both male and hermaphrodite gametophyte size. Antheridiogen was found to slow the growth of male and hermaphrodite gametophytes of the wild type and male gametophytes of the him1 mutant. These results are supportive of the idea that gender may be determined indirectly through antheridiogen’s effect on gametophyte growth.

scholarly journals Clinical Application of Liquid Biopsy in Targeted Therapy of Metastatic Colorectal Cancer

2017 ◽  
Vol 2017 ◽  
pp. 1-3 ◽  
Author(s):  
Jörg Trojan ◽  
Susanne Klein-Scory ◽  
Christine Koch ◽  
Wolff Schmiegel ◽  
Alexander Baraniskin
Keyword(s):  
Liquid Biopsy ◽  
Growth Factor Receptor ◽  
Circulating Tumor Dna ◽  
Response To Treatment ◽  
Close Monitoring ◽  
Wild Type ◽  
Secondary Resistance ◽  
Mutation Status ◽  
First Case ◽  
Ras Status

Background. Colorectal cancers (CRC) shed DNA into blood circulation. There is growing evidence that the analysis of circulating tumor DNA can be effectively used for monitoring of disease, to track tumor heterogeneity and to evaluate response to treatment. Case Presentation. Here, we describe two cases of patients with advanced CRC. The first case is about a patient with no available tissue for analysis of RAS mutation status. Liquid biopsy revealed RAS-wild-type and the therapy with anti-EGFR (epidermal growth factor receptor) monoclonal antibody cetuximab could be initiated. In the second case, the mutational profile of a patient with initial wild-type RAS-status was continually tracked during the course of treatment. An acquired KRAS exon 3 mutation was detected. The number of KRAS mutated fragments decreased continuously after the discontinuation of the therapy with EGFR-specific antibodies. Conclusion. Liquid biopsy provides a rapid genotype result, which accurately reproduces the current mutation status of tumor tissue. Furthermore, liquid biopsy enables close monitoring of the onset of secondary resistance to anti-EGFR therapy.

scholarly journals Genome-wide biases in the rate and molecular spectrum of spontaneous mutations in Vibrio cholerae and Vibrio fischeri

2016 ◽  
Author(s):  
Marcus M Dillon ◽  
Way Sung ◽  
Robert Sebra ◽  
Michael Lynch ◽  
Vaughn Cooper
Keyword(s):  
Vibrio Cholerae ◽  
Vibrio Fischeri ◽  
Purifying Selection ◽  
Base Substitution ◽  
Chromosome 2 ◽  
Spontaneous Mutations ◽  
Wild Type ◽  
Bacterial Genomes ◽  
Genome Wide ◽  
Mutation Spectra

The vast diversity in nucleotide composition and architecture among bacterial genomes may be partly explained by inherent biases in the rates and spectra of spontaneous mutations. Bacterial genomes with multiple chromosomes are relatively unusual but some are relevant to human health, none more so than the causative agent of cholera, Vibrio cholerae. Here, we present the genome-wide mutation spectra in wild-type and mismatch repair (MMR) defective backgrounds of two Vibrio species, the low-GC% squid symbiont V. fischeri and the pathogen V. cholerae, collected under conditions that greatly minimize the efficiency of natural selection. In apparent contrast to their high diversity in nature, both wild-type V. fischeri and V. cholerae have among the lowest rates for base-substitution mutations (bpsms) and insertion-deletion mutations (indels) that have been measured, below 10-3/genome/generation. V. fischeri and V. cholerae have distinct mutation spectra, but both are AT-biased and produce a surprising number of multi-nucleotide indels. Furthermore, the loss of a functional MMR system caused the mutation spectra of these species to converge, implying that the MMR system itself contributes to species-specific mutation patterns. Bpsm and indel rates varied among genome regions, but do not explain the more rapid evolutionary rates of genes on chromosome 2, which likely result from weaker purifying selection. More generally, the very low mutation rates of Vibrio species correlate inversely with their immense population sizes and suggest that selection may not only have maximized replication fidelity but also optimized other polygenic traits relative to the constraints of genetic drift.

Sign in / Sign up

Export Citation Format

Share Document