Formaldehyde Fixation of Drosophila Testes

Abstract

This protocol describes formaldehyde fixation of Drosophila testes. The procedure preserves chromosome morphology very well, allowing a clear visualization of the chromosome condensation–decondensation cycle. It also results in excellent preservation of microtubules for immunostaining. The main disadvantage of this fixation technique is its poor preservation of cell morphology, as viewed by phase-contrast optics. In addition, because it involves a rather hard squashing of formaldehyde-fixed testes, it results in meiotic figures which are flatter and larger than those obtained using methanol-acetone or paraformaldehyde fixation protocols.