Position‐effect variegation for an isoamylase in Drosophila melanogaster

Abstract

It has been shown that the rearrangement T(1; 2) OR 32 which has the Amy region inserted into the beterochromatic region of the X chromosome exhibits variegation for that particular isoamylase (band No. 2 on the zymogram) which the translocated element codes for. Many of the characteristics associated with the variegation phenomenon were detected. An extra Y chromosome present in the genome had a suppressive action on the variegation, i.e. more of the Amy2 component was produced. On the other hand, XO males showed no amylase activity in band position No. 2 on the zymogram. Some enhancement of amylase production by the transposed gene was observed in the progeny if a Y chromosome was present in the genome of the mother. Also did high temperature (29° C) enhance and low temperature (18° C) diminish amylase production by the variegating gene. 1971 Hereditas