scholarly journals The effect of an intronic polymorphism on alcohol dehydrogenase expression in Drosophila melanogaster.

Genetics ◽  
1994 ◽  
Vol 138 (2) ◽  
pp. 379-385 ◽  
Author(s):  
C C Laurie ◽  
L F Stam
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Selection ◽  
Alcohol Dehydrogenase ◽  
Evolutionary Dynamics ◽  
In Vitro Mutagenesis ◽  
Allozyme Polymorphism ◽  
Selection Models ◽  
Intronic Polymorphism ◽  
Lines Of Evidence

Abstract Several lines of evidence indicate that natural selection controls the frequencies of an allozyme polymorphism at the alcohol dehydrogenase (Adh) locus in Drosophila melanogaster. However, because of associations among sequence polymorphisms in the Adh region, it is not clear whether selection acts directly (or solely) on the allozymic site. This problem has been approached by using in vitro mutagenesis to distinguish among the effects on Adh expression of individual polymorphisms. This study shows that a polymorphism within the first Adh intron (delta 1) has a significant effect on the level of ADH protein. Like the allozyme, delta 1 shows a geographic cline in frequency, indicating that it may also be a target of natural selection. These results suggest that multisite selection models may be required to understand the evolutionary dynamics of individual loci.

scholarly journals THE ALCOHOL DEHYDROGENASE POLYMORPHISM IN POPULATIONS OF DROSOPHILA MELANOGASTER. I. SELECTION IN DIFFERENT ENVIRONMENTS

Genetics ◽  
1978 ◽  
Vol 90 (1) ◽  
pp. 161-191
Author(s):  
W van Delden ◽  
A C Boerema ◽  
A Kamping
Keyword(s):  
Drosophila Melanogaster ◽  
Alcohol Dehydrogenase ◽  
Experimental Evidence ◽  
Balancing Selection ◽  
Adult Survival ◽  
High Survival ◽  
High Humidity ◽  
Allozyme Polymorphism ◽  
Degree Of Dominance ◽  
Frequency Changes

ABSTRACT The allozyme polymorphism at the alcohol dehydrogenase locus in Drosophila melanogaster was studied in order to obtain experimental evidence about the maintenance of this polymorphism. Populations started with different initial allele frequencies from homozygous F and S lines showed a convergence of frequencies on regular food at 25°, leading to values equal to those in the base populations. These results were interpreted as due to some kind of balancing selection. In populations kept at 29.8°, a lower equilibrium F frequency was attained. Addition of ethanol and some other alcohols to the food gave a rapid increase in F frequency, and high humidity decreased the F frequency slightly. Combination or alternation of ethanol and high humidity had variable effects in the populations tested. For a further analysis of the allele-frequency changes, estimates were obtained for egg-to-adult survival under different conditions and for adult survival on ethanol-supplemented food. On ethanol food (both at regular and high humidity), egg-to-adult survival of SS homozygotes was considerably lower than that of the FF and FS genotypes. Under regular conditions of food, temperature and humidity, a tendency to heterozygote superiority was observed, while at high humidity a relative high survival of SS was noticed in some tests. Adult survival of SS was lower than that of FF, but FS was generally intermediate, though the degree of dominance differed between populations. The results are consistent with the hypothesis of the occurrence of selection at the Adh locus.

scholarly journals The population and evolutionary dynamics of bacteriophage: Why be temperate revisited

2019 ◽  
Author(s):  
Waqas Chaudhry ◽  
Nicole Vega ◽  
Adithi Govindan ◽  
Rodrigo Garcia ◽  
Esther Lee ◽  
...  
Keyword(s):  
Natural Selection ◽  
Evolutionary Dynamics ◽  
Natural Populations ◽  
Lytic Phage ◽  
Temperate Bacteriophage ◽  
Serial Transfer ◽  
Virulent Phage ◽  
E Coli ◽  
Resistant Refractory

AbstractBacteriophages are deemed either lytic (virulent) or temperate, respectively depending on whether their genomes are transmitted solely horizontally, or both horizontally and vertically. To elucidate the ecological and evolutionary conditions under which natural selection will favor the evolution and maintenance of lytic or temperate modes of phage replication and transmission, we use a comprehensive mathematical model of the dynamics of temperate and virulent phage in populations of bacteria sensitive and resistant to these viruses. For our numerical analysis of the properties of this model, we use parameters estimated with the temperate bacteriophage Lambda, λ, it’s clear and virulent mutants, andE. colisensitive and resistant - refractory to these phages. Using batch and serial transfer population dynamic and reconstruction experiments, we test the hypotheses generated from this theoretical analysis. Based on the results of this jointly theoretical and experimental study, we postulate the conditions under which natural selection will favor the evolution and maintenance of lytic and temperate modes of phage replication and transmission. A compelling and novel prediction thisin silico,in vitro, andin plasticostudy makes is lysogenic bacteria from natural populations will be resistant-refractory to the phage for which they are lysogenic as well as lytic phage sharing the same receptors as these temperate viruses.

scholarly journals Selection at the alcohol dehydrogenase locus in Drosophila melanogaster imposed by environmental ethanol

1975 ◽  
Vol 26 (3) ◽  
pp. 265-274 ◽  
Author(s):  
J. G. Oakeshott
Keyword(s):  
Drosophila Melanogaster ◽  
Alcohol Dehydrogenase ◽  
Ethanol Concentration ◽  
Developmental Time ◽  
Enzymic Activity ◽  
Regression Analyses ◽  
Percentage Survival ◽  
Alcohol Dehydrogenase Activity ◽  
Survival Differences

SUMMARYThis paper describes selective differences imposed by environmental ethanol on six genotypes at the alcohol dehydrogenase (Adh) locus in Drosophila melanogaster. Probit analyses were used to relate differences between the percentage survival of adults of different Adh genotypes to ethanol concentration. Regression analyses were used to relate differences between the pre-adult developmental times of different Adh genotypes to ethanol concentration. The directions of differences between some of the genotypes were found to differ in these two components of fitness. The differences in developmental time are linearly related to the differences in the in vitro alcohol dehydrogenase activity expressed by these genotypes. Percentage survival differences amongst adults are not linearly related to these differences in enzymic activity. The development of AdhF AdhF pre-adults is retarded the least on ethanol impregnated media but AdhFAdhS adults are most likely to survive on such media.

scholarly journals Use of in vitro mutagenesis to analyze the molecular basis of the difference in Adh expression associated with the allozyme polymorphism in Drosophila melanogaster.

Genetics ◽  
1991 ◽  
Vol 129 (2) ◽  
pp. 481-488
Author(s):  
M Choudhary ◽  
C C Laurie
Keyword(s):  
Drosophila Melanogaster ◽  
Amino Acid ◽  
Protein Level ◽  
Molecular Basis ◽  
Catalytic Efficiency ◽  
Amino Acid Replacement ◽  
Single Amino Acid ◽  
In Vitro Mutagenesis ◽  
The Difference

Abstract In natural populations of Drosophila melanogaster, the alcohol dehydrogenase (Adh) locus is polymorphic for two allozymes, designated Slow and Fast. Fast homozygotes generally have a two- to threefold higher ADH activity level than Slow homozygotes for two reasons: they have a higher concentration of ADH protein and the Fast protein has a higher catalytic efficiency. DNA sequencing studies have shown that the two allozymes generally differ by only a single amino acid at residue 192, which must therefore be the cause of the catalytic efficiency difference. A previous P element-transformation experiment mapped the difference in ADH protein level to a 2.3-kb HpaI/ClaI restriction fragment; which contains all of the Adh coding sequences but excludes all of the 5' flanking region of the distal transcriptional unit. Here we report the results of a site-directed in vitro mutagenesis experiment designed to investigate the effects of the amino acid replacement. This replacement has the expected effect on catalytic efficiency, but there is no detectable effect on the concentration of ADH protein estimated immunologically. This result shows that the average difference in ADH protein level between the allozymic classes is due to linkage disequilibrium between the amino acid replacement and one or more other polymorphisms within the HpaI/ClaI fragment. Sequence analysis of several Fast and Slow alleles suggested that the other polymorphism might be a silent substitution at nucleotide 1443, but another in vitro mutagenesis experiment reported here shows that this is not the case. Therefore, the molecular basis of the difference in ADH protein concentration between the allozymic classes remains an open question.

Hydrolysis of pyrethroids by carboxylesterases from Lucilia cuprina and Drosophila melanogaster with active sites modified by in vitro mutagenesis

2005 ◽  
Vol 35 (6) ◽  
pp. 597-609 ◽  
Author(s):  
Rama Heidari ◽  
Alan L. Devonshire ◽  
Bronwyn E. Campbell ◽  
Susan J. Dorrian ◽  
John G. Oakeshott ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Active Sites ◽  
Lucilia Cuprina ◽  
In Vitro Mutagenesis ◽  
Hydrolysis Of

scholarly journals Inferring weak selection from patterns of polymorphism and divergence at "silent" sites in Drosophila DNA.

Genetics ◽  
1995 ◽  
Vol 139 (2) ◽  
pp. 1067-1076 ◽  
Author(s):  
H Akashi
Keyword(s):  
Population Genetics ◽  
Drosophila Melanogaster ◽  
Natural Selection ◽  
Evolutionary Dynamics ◽  
Effective Population ◽  
Weak Selection ◽  
Fitness Effect ◽  
Synonymous Mutations ◽  
Synonymous Codons ◽  
Dna Mutations

Abstract Patterns of codon usage and "silent" DNA divergence suggest that natural selection discriminates among synonymous codons in Drosophila. "Preferred" codons are consistently found in higher frequencies within their synonymous families in Drosophila melanogaster genes. This suggests a simple model of silent DNA evolution where natural selection favors mutations from unpreferred to preferred codons (preferred changes). Changes in the opposite direction, from preferred to unpreferred synonymous codons (unpreferred changes), are selected against. Here, selection on synonymous DNA mutations is investigated by comparing the evolutionary dynamics of these two categories of silent DNA changes. Sequences from outgroups are used to determine the direction of synonymous DNA changes within and between D. melanogaster and Drosophila simulans for five genes. Population genetics theory shows that differences in the fitness effect of mutations can be inferred from the comparison of ratios of polymorphism to divergence. Unpreferred changes show a significantly higher ratio of polymorphism to divergence than preferred changes in the D. simulans lineage, confirming the action of selection at silent sites. An excess of unpreferred fixations in 28 genes suggests a relaxation of selection on synonymous mutations in D. melanogaster. Estimates of selection coefficients for synonymous mutations (3.6 < magnitude of Nes < 1.3) in D. simulans are consistent with the reduced efficacy of natural selection (magnitude of Nes < 1) in the three- to sixfold smaller effective population size of D. melanogaster. Synonymous DNA changes appear to be a prevalent class of weakly selected mutations in Drosophila.

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