The l(1)ts403 mutation is characterized by the multiple pleiotropic effects after temperature elevation. We detected some new effects of this mutation. They are
abnormalities of embryogenesis and oogenesis, various developmental abnormalities in the progeny of heat treated females. The mutation behaves as recessive one in terms of the disturbance of heat shock protein synthesis and survival after heat shock, while it is dominant regarding other characters such as high frequency of sex chromosomes nondisjunction in heat treated female meiosis and the disturbance of early embryogenesis in heated embryos. Therefore, part of these effects may be the result of the heat shock protein synthesis inhibition while others may be due to the heat modification of the
l(1)ts403 gene product necessary for some "house-keeping" functions.
Non-Mendelian inheritance of high thermosensitivity of early embryos and the
pattern of developmental abnormalities observed in the progeny of heated females suggest that the l(1)ts403 gene product is able to conformational changes under heat shock.