Functional significance of regulatory map and structural Amy variants in Drosophila melanogaster

Abstract

It was shown earlier that variants for the regulatory and structural components of the a-amylase gene-enzyme system in populations of D. melanogaster show moderate to strong linkage disequilibria suggesting selection. Here we demonstrate directly, that there are selective differences between particular combinations of regulatory variants of map genes, controlling a-amylase midgut activity patterns, and structural variants of a-amylase encoded by the Amy genes. Adult survival of stocks homozygous for different combinations of Amy and map variants was measured on carbohydrate solutions of starch, maltose and glucose, respectively. On starch, within Amy1 and Amy4'6 stocks, the map variant with extended a-amylase midgut activity pattern lived longer than the map variant with the small a-amylase midgut activity pattern. However, both Amy4'6 stocks lived longer on starch than the Amy1 stocks. On maltose and glucose no differences were recorded. Differences in survival on starch could be related to a-amylase activity levels. It is concluded that polymorphism of both the regulatory map genes and the structural Amy genes are important for determination of the selective differences between D. melanogaster stocks on starch.

Population Genetics and Evolution

“…Selection experiments performed with adults suggest indeed that some of the combinations of Amy and adult map variants tested show differences in viability under conditions when selection is operating on the a-amylase system (Klarenberg et al 1986a). Our data show that within Amy-1 and Amy4.6 isogenic strains there is a correlation between total a-amylase activity and map variation in adults (Fig.…”

Molecular evolution of the 5'-flanking regions of the duplicated Amy genes in Drosophila melanogaster species subgroup

“…The genes controlling the amylase expression are known to be polymorphic like the Amy structural genes. Extensive polymorphisms are found in the specific activity (Abe 1958;Kikkawa 1964), the inducibility (Matsuo and Yamazaki 1984;Yamazaki and Matsuo 1984), the glucose repression (Benkel and Hickey 1986) and the pattern of expression in midgut (Abraham and Doane 1979;Klarenberg et al 1986;Klarenberg, Sikkema, and Sharloo 1987). Since gene regulation is considered to be important for adaptive evolution (Willson 1975;Matsuo and Yamazaki 1984;Dickinson 199 1) and 5'flanking regions of genes usually play very important roles in gene regulation, it is interesting to examine the evolution of the 5'-flanking regions of the Amy genes in this species subgroup.…”

Adaptative significance of amylase polymorphism in Drosophila. III. Geographic patterns in Drosophila subobscura tissue-specific expression of amylase in adult midgut

“…The results on D P seudoobscura (Powell and Andjeljkovi6, 1983;Powell and Amato, 1984) and on D rrcelanogaster (Klarenberg et al, 1987) clearly reveal that different midgut activity phenotypes show selective differences in laboratory populations maintained on media with different starch concentrations. The results of Marinkovi6 et al (1984) on D subobscura have shown that there is a correlation between MAP-types and pre-adult developmental rate.…”