Colcemid effects on homologue pairing and crossing over during fetal mouse oogenesis

Summary Colcemid was administered to gestational day 13 female mice to test effects on homologue pairing, synapsis and recombination of fetal oogenesis. Pairing abnormalities were detected in pachytene oocytes by light and electron microscopy examination of bivalents and synaptonemal complexes. Reduction of total chiasmata per treated diplotene oocyte (22.74) compared to controls (31.07) was found.