ADH, α-GPDH and SOD enzyme activities of second and third chromosomal genotypes from two geographically different populations of Drosophila melanogaster

Abstract

ADH, α‐GPDH and SOD enzyme activities have been measured in lines of Drosophila melanogaster homozygous and/or heterozygous for chromosomes extracted from two different populatioi Globally the results demonstrate that factors other than structural genes are determining the observed pattern of enzyme activities. ADH and α‐GPDH activities are, however, more affected than SOD by these factors. Geographic origin, sex, chromosome, genetic background of the lines, containing regulatory genes in a broad sense, can be mentioned as the more relevant factors that influencing enzyme activities. A high and significant correlation is detected between ADH and α‐GPDH enzyme activities and it can be interpreted as due to linkage disequilibrium among these two loci. SOD activity shows a lesser correlation with ADH and α‐GPDH because it is less variable within population, i.e. it is a more canalized character. Finally, a principal component analysis, using the three enzyme systems shows that both populations are clearly separated, with a first principal component explaining 71.1 percent of the observed variance.