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

1975 ◽  
Vol 26 (1) ◽  
pp. 81-93 ◽  
Author(s):  
R. D. Ward

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.

1984 ◽  
Vol 43 (2) ◽  
pp. 181-190 ◽  
Author(s):  
Craig S. Tepper ◽  
Anne L. Terry ◽  
James E. Holmes ◽  
Rollin C. Richmond

SUMMARYThe esterase 6 (Est-6) locus in Drosophila melanogaster is located on the third chromosome and is the structural gene for a carboxylesterase (E.C.3.1.1.1) and is polymorphic for two major electromorphs (slow and fast). Isogenic lines containing X chromosomes extracted from natural populations and substituted into a common genetic background were used to detect unlinked factors that affect the activity of the Est-6 locus. Twofold activity differences of esterase 6 (EST 6) were found among males from these derived lines, which differ only in their X chromosome. These unlinked activity modifiers identify possible regulatory elements. Immunoelectrophoresis was used to estimate quantitatively the levels of specific cross-reacting material in the derived lines. The results show that the variation in activity is due to differences in the amount of EST 6 present. The data are consistent with the hypothesis that there is at least one locus on the X chromosome that regulates the synthesis of EST 6 and that this regulatory locus may be polymorphic in natural populations.


1976 ◽  
Vol 29 (4) ◽  
pp. 389 ◽  
Author(s):  
ADH Brown ◽  
DR Marshall ◽  
J Munday

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.


1981 ◽  
Vol 37 (3) ◽  
pp. 227-237 ◽  
Author(s):  
J. McKay

SUMMARYThe activity and thermostability of alcohol dehydrogenase (ADH) from 247 strains of Drosophila melanogaster were studied by spectrophotometric assay. The strains, in which second chromosomes had been made homozygous in a standard genetic background, were derived from five natural populations from diverse geographical and ecological sites. Evidence is presented that the majority of variation in ADH activity is attributable to the presence, in all five populations, of two electromorphs of the enzyme. However, some variation does exist between strains carrying the same electromorph, to some extent associated with variation hi body weight. Two strains showed atypical ADH activities. Variation in ADH thermostability was almost wholly attributable to the presence of two electromorphs; only two strains had enzymes with thermostabilities atypical of their electromorph. In the four strains with abnormal ADH properties the locus (loci) responsible map in the region of the Adh locus. Therelatively low level of heterogeneity within electrophoretic classes at this locus is discussed in view of recent findings at other enzyme loci in Drosophila.


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