GENETIC EVIDENCE FOR 'DARWINIAN' SELECTION AT THE MOLECULAR LEVEL. II. GENETIC ANALYSIS OF CYTOPLASMICALLY-INHERITED HIGH AND LOW SUPPRESSITIVITY IN SACCHAROMYCES CERVISIAE

1970 ◽  
Vol 12 (2) ◽  
pp. 340-346 ◽  
Author(s):  
Gerald H. Rank
Keyword(s):  
Mitochondrial Dna ◽  
Genetic Analysis ◽  
Molecular Level ◽  
Phenotypic Expression ◽  
Genetic Evidence ◽  
Darwinian Selection ◽  
Level Ii ◽  
Selection Of ◽  
Saccharomyces Cervisiae

A method was devised for the genetic analysis of cytoplasmically-inherited high and low suppressitivity in S. cervisiae thus enabling a test of the prediction, by the model of 'Darwinian' selection of mitochondrial DNA, that abnormal mitochondrial DNA of a high suppressitivity strain has a replicative advantage over abnormal mitochondrial DNA of a low suppressitivity strain. Support for the model was indicated by the ability of the suppressive factor resident in the high suppressitivity strain to control the phenotypic expression of suppressitivity in zygotes formed by crossing a low and high suppressitivity strain.

GENETIC EVIDENCE FOR 'DARWINIAN' SELECTION AT THE MOLECULAR LEVEL. I. THE EFFECT OF THE SUPPRESSIVE FACTOR ON CYTOPLASMICALLY-INHERITED ERYTHROMYCIN-RESISTANCE IN SACCHAROMYCES CEREVISIAE

1970 ◽  
Vol 12 (1) ◽  
pp. 129-136 ◽  
Author(s):  
Gerald H. Rank
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mitochondrial Dna ◽  
Molecular Level ◽  
Genetic Evidence ◽  
Erythromycin Resistance ◽  
Darwinian Selection ◽  
Level I

A study of the suppressive factor of Saccharomyces cerevisiae and its effects on the transmission of cytoplasmically-inherited erythromycin resistance showed that loss of erythromycin resistance was contingent on suppressitivity, and that strains carrying the suppressive factor continuously segregated progeny cells that lacked resistance. It was suggested that suppressitivity is due to the presence, in suppressive strains, of rapidly-replicating abnormal mitochondrial DNA, and that loss of erythromycin resistance (coded for by normal mitochondrial DNA) is due to the replicative superiority of abnormal mitochondrial DNA.

Genetic evidence for "Darwinian" selection at the molecular level. III. The effect of the suppressive factor on nuclearly and cytoplasmically inherited chloramphenicol resistance in S. cerevisiae

1972 ◽  
Vol 18 (1) ◽  
pp. 1-7 ◽  
Author(s):  
G. H. Rank ◽  
N. T. Bech-Hansen
Keyword(s):  
Deoxyribonucleic Acid ◽  
Molecular Level ◽  
Genetic Evidence ◽  
Nuclear Markers ◽  
Chloramphenicol Resistance ◽  
Darwinian Selection ◽  
Resistance Markers ◽  
Abnormal Mitochondria

Four nuclear and two cytoplasmic chloramphenicol-resistance markers were selected in S. cerevisiae. The effect of the suppressive factor (abnormal mitochondria deoxyribonucleic acid) on the inheritance of these markers was studied. Nuclear markers were shown to be unaffected by the suppressive factor, in contrast to the loss of cytoplasmically inherited chloramphenicol resistance upon the generation of the suppressive factor.

Evidence for genetic hybridization between Ixodes scapularis and Ixodes cookei

2017 ◽  
Vol 95 (8) ◽  
pp. 527-537 ◽  
Author(s):  
James W. Patterson ◽  
Anna M. Duncan ◽  
Kelsey C. McIntyre ◽  
Vett K. Lloyd
Keyword(s):  
Mitochondrial Dna ◽  
Genetic Analysis ◽  
New Brunswick ◽  
Nuclear Dna ◽  
Ixodes Scapularis ◽  
Companion Animals ◽  
Genetic Introgression ◽  
Eastern Canada ◽  
As Species ◽  
Intermediate Traits

Ixodes scapularis Say, 1821 (the black-legged tick) is becoming established in Canada. The northwards expansion of I. scapularis leads to contact between I. scapularis and Ixodes cookei Packard, 1869, a well-established tick species in Eastern Canada. Examination of I. cookei and I. scapularis collected from New Brunswick revealed ticks with ambiguous morphologies, with either a mixture or intermediate traits typical of I. scapularis and I. cookei, including in characteristics typically used as species identifiers. Genetic analysis to determine if these ticks represent hybrids revealed that four had I. cookei derived mitochondrial DNA but I. scapularis nuclear DNA. In one case, the nuclear sequence showed evidence of heterozygosity for I. scapularis and I. cookei sequences, whereas in the others, the nuclear DNA appeared to be entirely derived from I. scapularis. These data strongly suggest genetic hybridization between these two species. Ixodes cookei and hybrid ticks were readily collected from humans and companion animals and specimens infected with Borrelia burgdorferi Johnson et al., 1984, the causative agent of Lyme disease, were identified. These findings raise the issue of genetic introgression of I. scapularis genes into I. cookei and warrant reassessment of the capacity of I. cookei and I. cookei × I. scapularis hybrids to vector Borrelia infection.

scholarly journals THE SELECTION OF S. CEREVISIAE MUTANTS DEFECTIVE IN THE START EVENT OF CELL DIVISION

Genetics ◽  
1980 ◽  
Vol 95 (3) ◽  
pp. 561-577 ◽  
Author(s):  
Steven I Reed
Keyword(s):  
Cell Division ◽  
Genetic Analysis ◽  
Linkage Map ◽  
Nuclear Genes ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Mating Pheromone ◽  
Preliminary Characterization ◽  
Complementation Groups ◽  
Selection Of

ABSTRACT Thirty-three temperature-sensitive mutations defective in the start event of the cell division cycle of Saccharomyces cereuisiae were isolated and subjected to preliminary characterization. Complementation studies assigned these mutations to four complementation groups, one of which, cdc28, has been described previously. Genetic analysis revealed that these complementation groups define single nuclear genes, unlinked to one another. One of the three newly identified genes, cdc37, has been located in the yeast linkage map on chromosome IV, two meiotic map units distal to hom2.—Each mutation produces stage-specific arrest of cell division at start, the same point where mating pheromone interrupts division. After synchronization at start by incubation at the restrictive temperature, the mutants retain the capacity to enlarge and to conjugate.

Evidence for Positive Darwinian Selection of Vip Gene in Bacillus thuringiensis

2007 ◽  
Vol 34 (7) ◽  
pp. 649-660 ◽  
Author(s):  
Jinyu Wu ◽  
Fangqing Zhao ◽  
Jie Bai ◽  
Gang Deng ◽  
Song Qin ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Positive Darwinian Selection ◽  
Darwinian Selection ◽  
Selection Of

scholarly journals Dietary fat clearance in type V hyperlipoproteinaemia secondary to a rare variant of human apolipoprotein E: the apolipoprotein E3 (Arg 136 → Ser)

2000 ◽  
Vol 83 (6) ◽  
pp. 615-622 ◽  
Author(s):  
Bernard Vialettes ◽  
Pascal Reynier ◽  
Catherine Atlan-Gepner ◽  
Nadia Mekki ◽  
Laurence Lesluyes-Mazzochi ◽  
...  
Keyword(s):  
Phenotypic Expression ◽  
Present Case Report ◽  
Human Apolipoprotein ◽  
Low Fat Diet ◽  
Mutant Variant ◽  
Restriction Polymorphism ◽  
Polymerase Chain ◽  
Type V ◽  
Selection Of

This present case report describes two siblings with severe type V hyperlipoproteinaemia, diagnosed very early in life and due to the combination of the common apolipoprotein (Apo) E2 allele and a rare mutant variant of ApoE, ApoE3 (Arg 136 → Ser). Phenotyping of ApoE falsely identified E2/E2 phenotype. The presence of mutated ApoE was suspected on an unusual restriction polymorphism of a Hha 1 restriction site and confirmed by sequence analysis of the cloned polymerase chain reaction fragment of exon 4 and familial segregation study. The severity of the hypertriacylglycerolaemia was modulated by the lipid content of the diet. A low-fat diet enriched in medium-chain triacylglycerol (TAG) decreased but did not normalize plasma TAG levels in both affected patients of the pedigree. A standardized lipid-enriched test meal showed a marked impairment of TAG-rich lipoprotein (TRL) clearance, especially the exogeneous TRL bearing ApoB-48 which still represented 79 % of total TRL 7 h after the fat load. Finally, differences between the male and female siblings with the existence of a consanguine relationship in their parents suggested the involvement of other genetic factors in modulating the severity of phenotypic expression. This observation reinforces the usefulness of genotyping of ApoE for the characterization of genetic hypertriacylglycerolaemia and selection of the appropriate diet and treatment.

The Weight of Fear of Violence in Household Budgets

2021 ◽  
pp. 073401682110383
Author(s):  
Bruno Truzzi ◽  
Marcelo Justus ◽  
Henrique C. Kawamura ◽  
Thomas V. Conti
Keyword(s):  
Instrumental Variables ◽  
Regularization Method ◽  
Household Level ◽  
Household Spending ◽  
Goods And Services ◽  
Level Ii ◽  
The Stability ◽  
The Relationship ◽  
Selection Of

This article investigates the relationship between the perception of violence and the spending on security goods and services in households. Individual microdata from a random national survey on family budget carried out in Brazil in 2008-2009 were used for modeling the household spending using two instrumental variables. The stability of results was checked by applying the Lasso-Gaussian regularization method in the selection of the statistically significant variables. Positive relationships were found between household spending on security goods and services and (i) the fear of insecurity at the household level, (ii) the neighbors’ spending on security, and (iii) the registered criminality, but no evidence was found on the relationship between the role of police on household spending on security goods and services.

scholarly journals A Novel Genetic Pathway of Human Immunodeficiency Virus Type 1 Resistance to Stavudine Mediated by the K65R Mutation

2003 ◽  
Vol 77 (10) ◽  
pp. 5685-5693 ◽  
Author(s):  
J. Gerardo García-Lerma ◽  
Hamish MacInnes ◽  
Diane Bennett ◽  
Patrick Reid ◽  
Soumya Nidtha ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Phenotypic Expression ◽  
Cross Resistance ◽  
Phenotypic Characterization ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Selection Of

ABSTRACT Stavudine (d4T) and zidovudine (AZT) are thymidine analogs widely used in the treatment of human immunodeficiency virus type 1 (HIV-1)-infected persons. Resistance to d4T is not fully understood, although the selection of AZT resistance mutations in patients treated with d4T suggests that both drugs have similar pathways of resistance. Through the analysis of genotypic changes in nine recombinant viruses cultured with d4T, we identified a new pathway for d4T resistance mediated by K65R, a mutation not selected by AZT. Passaged viruses were derived from treatment-naïve persons or HIV-1HXB2 and had wild-type reverse transcriptase (RT) or T215C/D mutations. K65R was selected in seven viruses and was associated with a high level of enzymatic resistance to d4T-triphosphate (median, 16-fold; range, 5- to 48-fold). The role of K65R in d4T resistance was confirmed in site-directed mutants generated in three different RT backgrounds. Phenotypic assays based on recombinant single-cycle replication or a whole-virus multiple replication cycle were unable to detect d4T resistance in d4T-selected mutants with K65R but detected cross-resistance to other nucleoside RT inhibitors. Four of the six viruses that had 215C/D mutations at baseline acquired the 215Y mutation alone or in association with K65R. Mutants having K65R and T215Y replicated less efficiently than viruses that had T215Y only, suggesting that selection of T215Y in patients treated with d4T may be favored. Our results demonstrate that K65R plays a role in d4T resistance and indicate that resistance pathways for d4T and AZT may not be identical. Biochemical analysis and improved replication assays are both required for a full phenotypic characterization of resistance to d4T. These findings highlight the complexity of the genetic pathways of d4T resistance and its phenotypic expression.

A mating mechanism to generate diversity for the Darwinian selection of DNA-encoded synthetic molecules

2021 ◽  
Author(s):  
Balayeshwanth R. Vummidi ◽  
Lluc Farrera-Soler ◽  
Jean-Pierre Daguer ◽  
Millicent Dockerill ◽  
Sofia Barluenga ◽  
...  
Keyword(s):  
Darwinian Selection ◽  
Synthetic Molecules ◽  
Selection Of
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