Loosing one allele of mad2 affects the fidelity of chromosome segregation in meiosis I and fertility.

<p>(A) Chromosome spreads were performed in metaphase I (6 hours after GVBD) and metaphase II (2 hours after PBE). Chromosomes are stained with propidium iodide (red), and kinetochores with CREST serum <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0001165#pone.0001165-Furuta1" target="_blank">[30]</a>. Shown are one euploid and one aneuploid metaphase II spread of <i>mad2+/−</i> oocytes. (B) Quantification of aneuploid oocytes in metaphase I and II harboring more or less than 20 chromosomes. n indicates the number of interpretable metaphase spreads obtained. 8 <i>mad2+/−</i> mice were analysed in four independent experiments. (C) 21% of female mad2+/− mice are sterile. (D) <i>mad2−/−</i> embryos are not viable and therefore the litter size is expected to be 25% lower in the heterozygote crosses. The average litter size from <i>mad2+/−</i> crosses is reduced to 43% compared to wild type crosses, and to 57,6% compared to the expected litter size.