ISSN:
1573-4927
Keywords:
Drosophila melanogaster
;
Cu/Zn superoxide dismutase
;
quantitative variation
;
modifiers
;
null allele
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract We have studied genetic variation for levels of activity of the enzyme superoxide dismutase (SOD) in Drosophila melanogaster. We have constructed 34 lines homozygous for a given second and a given third chromosome derived from eight original lines; all lines were homozygous for the “fast” (F) allele of Sod. The variation in the relative levels of SOD CRM ranges from 1 to 1.6. The second chromosomes modify the SOD level, even though the structural Sod locus is in the third chromosome, and the specific effect of a given second chromosome depends on the particular third chromosome with which it is combined. This indicates that the variation in SOD content is controlled by polygenic modifiers present in the second (and in the third) chromosome. In addition to these trans-acting modifiers, we have isolated a cis-acting element (Sod CAl ) that reduces SOD CRM levels to 3.5% of a typical F/F homozygote. Sod CAl is either a mutation in a regulatory site closely linked to the structural locus or a change in the coding sequence affecting the rate of degradation of the enzyme.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00502785
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