scholarly journals Opposing Modes of Selection on the Alcohol Dehydrogenase Locus in Drosophila Melanogaster

1980 ◽  
Vol 33 (1) ◽  
pp. 105 ◽  
Author(s):  
JG Oakeshott ◽  
JB Gibson ◽  
PR Anderson ◽  
A Champ
Keyword(s):  
Aqueous Solution ◽  
Drosophila Melanogaster ◽  
Alcohol Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Natural Populations ◽  
Natural Environments ◽  
Experimental Conditions ◽  
The Third ◽  
Alcohol Dehydrogenase Activity ◽  
Survival Differences

Three experiments have been carried out which show that exogenous environments of ethanol impose selection on the alcohol dehydrogenase (Adh) locus of D. melanogaster. This locus is widely polymorphic for two alleles, AdhF and Adhs, and AdhF generally produces about twice as much alcohol dehydrogenase activity as Adhs. In the first experiment, AdhF IAdhF and AdhF/Adhs flies survived equally often and Adhs/Adhs flies less frequently after exposure for 7 days to medium impregnated with ethanol. The same pattern of survival differences was found in the second experiment in which flies were exposed for 1 day to an aqueous solution of ethanol and sucrose. In contrast, in the third experiment survival was scored after exposure for 45-min to ethanol fumes, and Adhs/ Adhs flies survived more often than AdhF/Adhs, both these genotypes surviving more frequently than Adh F / Adh F. We doubt whether anyone of the three experiments by itself adequately represents the ecology of natural populations of D. melanogaster exposed to ethanol. It is likely that mixtures of the three experimental conditions approximate more closely the natural environments and therefore we suggest that, overall, selection might favour intermediate levels of alcohol dehydrogenase activity, producing a net advantage for heterozygotes at the Adh locus.

scholarly journals GENETIC AND BIOCHEMICAL BASIS OF ENZYME ACTIVITY VARIATION IN NATURAL POPULATIONS. I. ALCOHOL DEHYDROGENASE IN DROSOPHILA MELANOGASTER

Genetics ◽  
1978 ◽  
Vol 89 (2) ◽  
pp. 371-388
Author(s):  
John F McDonald ◽  
Francisco J Ayala
Keyword(s):  
Gene Regulation ◽  
Drosophila Melanogaster ◽  
Alcohol Dehydrogenase ◽  
Natural Populations ◽  
Difficult Problem ◽  
Regulatory Genes ◽  
Biochemical Basis ◽  
Evolutionary Consequence ◽  
The Third ◽  
Adh Activity

ABSTRACT Recent studies by various authors suggest that variation in gene regulation may be common in nature, and might be of great evolutionary consequence; but the ascertainment of variation in gene regulation has proven to be a difficult problem. In this study, we explore this problem by measuring alcohol dehydrogenase (ADH) activity in Drosophila melanogaster strains homozygous for various combinations of given second and third chromosomes sampled from a natural population. The structural locus (Adh) coding for ADH is on the second chromosome. The results show that: (1) there are genes, other than Adh, that affect the levels of ADH activity; (2) at least some of these "regulatory" genes are located on the third chromosome, and thus are not adjacent to the Adh locus; (3) variation exists in natural populations for such regulatory genes; (4) the effect of these regulatory genes varies as they interact with different second chromosomes; (5) third chromosomes with high-activity genes are either partially or completely dominant over chromosomes with low-activity genes; (6) the effects of the regulatory genes are pervasive throughout development; and (7) the third chromosome genes regulate the levels of ADH activity by affecting the number of ADH molecules in the flies. The results are consistent with the view that the evolution of regulatory genes may play an important role in adaptation.

scholarly journals Adaptedness of Variants at an Alcohol Dehydrogenase Locus in Bromus mollis L. (Soft Bromegrass)

1976 ◽  
Vol 29 (4) ◽  
pp. 389 ◽  
Author(s):  
ADH Brown ◽  
DR Marshall ◽  
J Munday
Keyword(s):  
Alcohol Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Dry Matter ◽  
Animal Species ◽  
Natural Populations ◽  
Continuous Flooding ◽  
Naturally Occurring ◽  
Alcohol Dehydrogenase Activity ◽  
Adh Activity ◽  
Bromus Mollis

Alcohol dehydrogenase is highly polymorphic in many plant and animal species. Here we report evidence that the naturally occurring, electrophoretically detectable allozyme variants of the AdhlB locus in B. mollis can respond differentially to environmental stresses. It is argued that alcohol dehydrogenase activity is specifically involved in response to these stresses. Crude extracts of predominantly selfed seeds sampled from plants of known Adh1B genotype were assayed for their ADH activity in the forward and backward reactions. The seeds from Adh~B Adh~B plants produced extracts about 12 % less active in both directions than seeds from their Adh~BAdh~B counterparts. Such Adh~BAdh~B plants were also shown to produce about 13% more dry matter when grown under continuous flooding in the greenhouse whereas no difference between genotypes was detected in control pots. The seeds of Adh~B Adh~B plants showed an advantage over the alternative homozygotes in more rapid germination at 2�C, but no difference was found at 15�C. Thus the variants are differentially adapted, and this is likely to playa role in the maintenance of the polymorphism in natural populations.

scholarly journals Alcohol dehydrogenase activity in Drosophila melanogaster: a quantitative character

1975 ◽  
Vol 26 (1) ◽  
pp. 81-93 ◽  
Author(s):  
R. D. Ward
Keyword(s):  
Drosophila Melanogaster ◽  
Alcohol Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Structural Gene ◽  
Genetic Background ◽  
Quantitative Character ◽  
Alcohol Dehydrogenase Activity ◽  
Activity Modifiers ◽  
Selection For ◽  
Adh Activity

SUMMARYAlcohol dehydrogenase activity in Drosophila melanogaster may be considered as a quantitative character, since it shows many features typically associated with such traits. Although strains with the electrophoretically fast phenotype generally have activities greater than those with the slow phenotype, presumably reflecting differences in the nucleotide sequences of the structural alleles, within each electrophoretic class there is considerable variation in activity. The expression of the structural gene, in terms of ADH activity, is to some extent regulated by its genetic background. Strains homozygous for particular structural alleles respond to divergent directional selection for ADH activity. Modifiers have been located to the X, second and third chromosomes.

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.

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