Using second- or third-chromosome substitution lines of
Drosophila melanogaster, the genetic
variation of inducibility and amylase specific activities in three media
(starch, normal and glucose)
were investigated. Genetic factors on both the second and third
chromosomes were responsible for
the variation in amylase specific activity and inducibility. In glucose
medium, the genetic variance
of amylase specific activity estimated for the second-chromosome substitution
lines was larger than
that for the third-chromosome substitution lines; however, for starch
medium and inducibility, the
variance was larger for the third-chromosome substitution lines. High
correlations for the second-chromosome substitution lines and low
correlations for the third-chromosome substitution lines
were observed for amylase specific activities in different media. These
results suggest that the
genetic factor(s) responsible for inducibility or amylase activity
variation in an induced medium
such as starch should be on the third chromosome and those in the
non-induced medium such as
glucose should be on the second chromosome. The functional roles of the
factors on the second
and third chromosomes would be the repression and induction of amylase,
respectively.
Genetic and molecular analysis of an allelic series of cop1 mutants suggests functional roles for the multiple protein domains.
