Genetic analysis of natural populations of Drosophila melanogaster in Japan. VI Differential regulation of duplicated amylase loci and degree of dominance of amylase activity in different environments.

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Abstract
The degrees of dominance of amylase activity, responsiveness to inducing (or repressive) environment, the activity of one allozyme relative to that of the other duplicated locus, and trans- or cis-action of controlling elements were investigated using 10 homozygous lines from a natural population in Japan. The main findings are: (1) Genetic variation in specific activity, responsiveness as well as relative activity of duplicated genes were found. (2) The degree of dominance of amylase activity drastically changed in different environments. The heterozygous amylase activity in starch food was almost the same as the parenteral value with lower activity (h=1.29 .+-. 0.39, complete recessive). On the other hand, the enzyme activity of heterozygote in normal food was closer to the parent with higher activity (h=0.26 .+-. 0.07, high dominance), indicating that the manner of amylase regulation is trans-action and also is affected by the environments. (3) The relative activity of one of the two duplicated amylase loci on the same chromosome was affected by an allozyme on the homologous chromosome. In other words, the regulation of duplicated amylase genes was trans-action and partially differentiated, but high correlation of the enyzme activity between the two duplicated genes on the same chromosome also indicated the coordinated regulation.