scholarly journals A COMPARISON OF TWO-POINT, THREE-POINT AND DELETION MAPPING IN THE C CISTRON OF RHIZOBIOPHAGE 16–3, WITH AN EXPLANATION FOR THE RECOMBINATION PATTERN

Genetics ◽  
1980 ◽  
Vol 94 (2) ◽  
pp. 249-263
Author(s):  
LÁszlÓ Orosz ◽  
Katalin RostÁs ◽  
Rollin D Hotchkiss
Keyword(s):  
Fine Structure ◽  
High Frequency ◽  
Rhizobium Meliloti ◽  
General Tendency ◽  
Deletion Mapping ◽  
Structure Mapping ◽  
Mapping Data ◽  
Correct Order ◽  
Point Mapping ◽  
Double Crossovers

ABSTRACT A general tendency for additivity prevailed in recombination frequencies for two-point fine-structure mapping of 14 mutants in the C cistron of Rhizobium meliloti phage 16-3, with little evidence of any marker effect. Intracistronic three-point mapping indicated that double crossovers are rare. Deletion mapping indicated that the two- and three-point mapping data gave the correct order of the mutations. A high frequency (5 to 8%) of c/c+ heterozygotic phage progenies was observed in standard crosses. This pattern implies formation of a relatively long region of heterozygosity. Together with the results of the three-point tests, it suggests certain properties of the branch migration and resolution steps envisioned in current mechanisms of recombination.

METHODS FOR ANALYSIS OF THE C CISTRON OF TEMPERATE PHAGE 16–3 OF RHIZOBIUM MELILOTI

Genetics ◽  
1980 ◽  
Vol 94 (2) ◽  
pp. 265-276
Author(s):  
LÁszló Orosz
Keyword(s):  
Fine Structure ◽  
Rhizobium Meliloti ◽  
Point Mutations ◽  
Cumulative Effect ◽  
Temperate Phage ◽  
Deletion Mutants ◽  
Temperature Sensitive ◽  
Structure Mapping ◽  
Repressor Protein ◽  
Sensitive Allele

ABSTRACT A series of clear mutants of the temperate phage 16-3 of Rhizobium meliloti were isolated that included various point and deletion mutants ofthe Ccistron, coding for the phage repressor. It was observed that recombinant genotypes, such as c+ and ti (temperature-sensitive allele), which form turbid plaques, can be detected quantitatively as lysogenic colonies and scored even at frequencies as low as 10-6. Point mutations, deletions and the autonomy of intracistronic second-site mutations were characterized by this method. Further analysis has shown that each possible pair from three ti mutants gave non-conditional clear recombinants. It was shown that these latter bear the two initial ti mutations, suggesting a cumulative effect of two conditional mutations on the structure of the repressor protein. The double mutants were utilized in fine-structure mapping of the Ccistron.

scholarly journals FINE STRUCTURE MAPPING OF THE am (GDH) LOCUS OF NEUROSPORA

Genetics ◽  
1983 ◽  
Vol 105 (2) ◽  
pp. 293-307
Author(s):  
John A Rambosek ◽  
John A Kinsey
Keyword(s):  
Fine Structure ◽  
Deletion Mapping ◽  
Structure Mapping ◽  
Marker Analysis

ABSTRACT Utilizing a combination of flanking marker analysis and deletion mapping we have constructed a fine structure map of the am locus which includes 63 point mutants and ten unique deletions. Positions of point mutants can be rapidly assigned to one of 13 segments within the gene on the basis of crosses to nine deletion strains.

Mutations at the Saccharomyces cerevisiae SUP4 tRNA Tyr Locus: Isolation, Genetic Fine-Structure Mapping, and Correlation with Physical Structure

1982 ◽  
Vol 2 (12) ◽  
pp. 1501-1513
Author(s):  
Janet Kurjan ◽  
Benjamin D. Hall
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fine Structure ◽  
Physical Structure ◽  
Mapping Technique ◽  
Structure Mapping ◽  
Isolation And Characterization ◽  
Qualitative Estimate ◽  
Genetic Fine Structure ◽  
Entire Gene

The SUP4 tRNA Tyr locus in Saccharomyces cerevisiae has been studied by the isolation and characterization of mutations at the SUP4 gene which result in the loss of suppressor function. Most of the mutations act as single-site mutations, whereas about a third of the mutations are deletions of the entire gene. Two meiotic fine-structure maps of the gene were made. The first mapping technique placed 10 mutations plus the sup4 + anticodon on a map by a measurement of levels of recombination between pairs of mutations. The second map utilized a more qualitative estimate of recombination frequency, allowing 69 mutations and the sup4 + anticodon to be mapped. The maps were compared with the physical structure of the gene for the 34 mutations whose nucleotide alteration has been determined by DNA sequencing (Koski et al., Cell 22 :415-425, 1980; Kurjan et al., Cell 20 :701-709, 1980). Both maps show a good correlation with the physical structure of the gene, even though certain properties of genetic fine-structure maps, such as marker effects and “map expansion,” were seen.

scholarly journals A CIS-DOMINANT MUTATION IN ASPERGILLUS NIDULANS AFFECTING THE EXPRESSION OF THE amdS GENE IN THE PRESENCE OF MUTATIONS IN THE UNLINKED GENE, amdA

Genetics ◽  
1982 ◽  
Vol 102 (2) ◽  
pp. 139-147
Author(s):  
Michael J Hynes
Keyword(s):  
Fine Structure ◽  
Genetic Analysis ◽  
Genetic Mapping ◽  
Gene Function ◽  
The Other ◽  
Structure Mapping ◽  
Dominant Mutation ◽  
Amds Gene ◽  
Very High ◽  
New Mutations

ABSTRACT A mutant producing very high levels of the acetamidase enzyme encoded by the amdS gene has been isolated in a strain containing the amdA7 mutation, which itself causes high levels of this enzyme. Genetic analysis has shown that this mutation, designated amdI66, is adjacent to the amdS gene and is cis-dominant in its effect. The amdI66 mutation has little effect on amdS expression when present in strains not containing the amdA7 mutation. Two other amdA mutations investigated also interact with the amdI66 mutation to result in high acetamidase levels. No interaction between amdI66 and any of the other putative regulatory genes affecting amdS expression has been observed. The amdI66 mutation has been located by fine structure mapping at the extreme end of the controlling region, which has previously been defined by genetic mapping (Hynes 1979). Analysis of this region has been extended by mapping new mutations resulting in loss of amdS expression. One of these defines the most extreme site capable of mutation to loss of gene function found so far.

scholarly journals Evaluation of the information content of RNA structure mapping data for secondary structure prediction

RNA ◽  
2010 ◽  
Vol 16 (6) ◽  
pp. 1108-1117 ◽  
Author(s):  
S. Quarrier ◽  
J. S. Martin ◽  
L. Davis-Neulander ◽  
A. Beauregard ◽  
A. Laederach
Keyword(s):  
Secondary Structure ◽  
Information Content ◽  
Rna Structure ◽  
Structure Prediction ◽  
Secondary Structure Prediction ◽  
Structure Mapping ◽  
Mapping Data ◽  
Rna Structure Mapping

Sensitivity to Interaural Temporal Disparities of Low- and High-Frequency Neurons in the Superior Olivary Complex. I. Heterogeneity of Responses

1997 ◽  
Vol 78 (3) ◽  
pp. 1222-1236 ◽  
Author(s):  
Ranjan Batra ◽  
Shigeyuki Kuwada ◽  
Douglas C. Fitzpatrick
Keyword(s):  
Fine Structure ◽  
High Frequency ◽  
Complex I ◽  
General Trend ◽  
Free Field ◽  
Low Frequency ◽  
Superior Olivary Complex ◽  
Field Range ◽  
Multiple Units ◽  
Additional Phase

Batra, Ranjan, Shigeyuki Kuwada, and Douglas C. Fitzpatrick. Sensitivity to interaural temporal disparities of low- and high-frequency neurons in the superior olivary complex. I. Heterogeneity of responses. J. Neurophysiol. 78: 1222–1236, 1997. Interaural temporal disparities (ITDs) are a cue for localization of sounds along the azimuth. Listeners can detect ITDs in the fine structure of low-frequency sounds and also in the envelopes of high-frequency sounds. Sensitivity to ITDs originates in the main nuclei of the superior olivary complex (SOC), the medial and lateral superior olives (MSO and LSO, respectively). This sensitivity is believed to arise from bilateral excitation converging on neurons of the MSO and ipsilateral excitation converging with contralateral inhibition on neurons of the LSO. Here we investigate whether the sensitivity of neurons in the SOC to ITDs can be adequately explained by one of these two mechanisms. Single and multiple units ( n = 124) were studied extracellularly in the SOC of unanesthetized rabbits. We found units that were sensitive to ITDs in the fine structure of low-frequency (<2 kHz) tones and also units that were sensitive to ITDs in the envelopes of sinusoidally amplitude-modulated high-frequency tones. For both categories there were “peak-type” units that discharged maximally at a particular ITD across frequencies or modulation frequencies. These units were consistent with an MSO-type mechanism. There were also “trough-type” units that discharged minimally at a particular ITD. These units were consistent with an LSO-type mechanism. There was a general trend for peak-type units to be located in the vicinity of the MSO and for trough-type units to be located in the vicinity of the LSO. Units of both types appeared to encode ITDs within the estimated free-field range of the rabbit (±300 μs). Many units had varying degrees of irregularities in their responses, which manifested themselves in one of two ways. First, for some units there was no ITD at which the response was consistently maximal or minimal across frequencies. Instead there was an ITD at which the unit consistently responded at some intermediate level. Second, a unit could display considerable jitter from frequency to frequency in the ITD at which it responded maximally or minimally. Units with irregular responses had properties that were continuous with those of other units. They therefore appeared to be variants of peak- and trough-type units. The irregular responses could be modeled by assuming additional phase-locked inputs to a neuron in the MSO or LSO. The function of irregularities may be to shift the ITD sensitivity of a neuron without requiring changes in the anatomic delays of its inputs.

scholarly journals A directional, high-frequency chromosomal mobilization system for genetic mapping of Rhizobium meliloti.

1992 ◽  
Vol 174 (1) ◽  
pp. 324-326 ◽  
Author(s):  
S Klein ◽  
K Lohman ◽  
R Clover ◽  
G C Walker ◽  
E R Signer
Keyword(s):  
Genetic Mapping ◽  
High Frequency ◽  
Rhizobium Meliloti
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