Figure 2

Chromosome defects of the yem¹/Df3450 mature oocytes. The oocytes were treated as indicated in the experimental procedures prior to proceeding with the staining of the meiotic spindles. A - Projections of confocal sections showing meiotic spindles. The microtubules were revealed with anti-tubulin antibodies (green) and the condensed chromatin with anti-Phospho-histone H3 antibodies (red). The Drosophila oocyte spindle is acentriolar and nucleates at the chromatin mass as shown in (a). Late prometaphase is characterized by the non exchange 4^th chromosomes budding over the masses of the chiasmate chromosomes (b). In a fully mature stage 14 oocyte the exchange chromosomes are arrested at metaphase I whereas the achiasmate 4^th chromosomes undergo anaphase I (c). Note the irregular chromatin mass of the yem¹ exchange chromosomes (d). Scale: the bar represents 5 μm. B - Conventional epifluorescence pictures. Mutant and wild type oocytes were stained for DNA (DAPI) and the spindle with anti alpha-tubulin antibody (red). This gallery displays various phenotypic classes. Scale bar equals 5 μm. C-F - Histograms representing the ratio of the different phenotypic classes analyzed in this work. The first histogram represents the analysis of the conspicuous defects observed on a large number (n = 136) of oocytes. A detailed analysis was performed on a 95 spindles fraction. (n) Represents the number of oocytes scored. Df represents Df3450. To determine whether quantitative differences between two classes are significant, we used the two-tailed distribution of Fischer'exact test http://www.graphpad.com/quickcalcs/. The p-value states the probability for the null-hypothesis (i.e, that the differences are due to sampling variations).