Developmental-Genetic Studies of Tissue-Cultured Eye- Antennal Discs of <i>Drosophila melanogaster</i>

Abstract

1. Eye-antennal discs and cephalic complexes removed from mature third-instar larvae of a wild strain or various mutants of D. melanogaster were cultured in vitro in a synthetic medium, in order to invesitgate differences of metamorphic hormones among these strains.2. Ten cephalic complexes of Oregon-R larvae provide in a hanging-drop culture the optimum concentration of the metamorphic hormone for promoting growth and differentiation of eye-antennal discs removed from the cephalic complexes of Oregon- R larvae.3. The cephalic complex of various eye-color mutant larvae (bw, v, cn, v bw, cn bw or w) has a similar effect upon growth and differentiation of eye-antennal discs, secreting the metamorphic hormone.4. The metamorphic hormone secreted from the endocrine organ in the cephalic complex of B, bar-3 or Dp/In(3L)p, In(3R)c, sbel(3)e larvae seems to be qualitatively different from that of Oregon-R or various other eye-color mutants. Dp/In(3L)p, - In(3R)c, sbel(3)e mutant seems to be different from B or bar-3 mutant in respect to the quantity of the metamorphic hormone, and the eye-antennal discs of this strain are not affected either by the metamorphic hormone of Oregon-R or various eye-color mutant larvae.5. These facts suggest that the genic action appears simultaneously in both, cephalic complexes and eye-antennal discs.