Fischbach K F, Technau G
Dev Biol. 1984 Jul;104(1):219-39. doi: 10.1016/0012-1606(84)90050-2.
In the small-optic-lobes (sol) and sine oculis (so) mutants of Drosophila melanogaster extensive cell death occurs in the optic lobes during the first half of pupal development. Gynandromorph flies show that the sol mutation acts primarily on cells of the medulla cortex. Degeneration of medullar ganglion cells occurs at an early stage of cellular differentiation, when their axons have not yet participated in the formation of the second optic chiasma. The so gene, on the other hand, acts on the eye anlagen. The analysis of chimeric flies demonstrates that degeneration in the optic lobes of so flies is a consequence of eye reduction. At the level of the second optic chiasma extensive axonal degeneration can be observed in the mutant. Neurons seem to die after their failure to establish a sufficient number of functional contacts. In sol;so double mutants, the mutational effects are cumulative causing complete degeneration of columnar cell types in pupae without any eye anlage. The tiny rudiments of the optic lobes in eyeless double mutants still contain tangential neurons of the medulla and of the lobula complex. The central brain is reduced in size due to the missing visual fibers, however, its overall appearance is surprisingly normal.
在黑腹果蝇的小眼叶（sol）和无眼（so）突变体中，在蛹发育的前半阶段，视叶中会发生广泛的细胞死亡。雌雄嵌合体果蝇表明，sol突变主要作用于髓质皮质的细胞。髓质神经节细胞的退化发生在细胞分化的早期阶段，此时它们的轴突尚未参与第二个视交叉的形成。另一方面，so基因作用于眼原基。对嵌合体果蝇的分析表明，so果蝇视叶中的退化是眼睛缩小的结果。在突变体中，在第二个视交叉水平可以观察到广泛的轴突退化。神经元似乎在未能建立足够数量的功能连接后死亡。在sol;so双突变体中，突变效应是累积的，导致蛹中柱状细胞类型完全退化，且没有任何眼原基。无眼双突变体中视叶的微小残基仍然包含髓质和小叶复合体的切向神经元。由于缺少视觉纤维，中枢脑的尺寸减小，然而，其整体外观出人意料地正常。
