B. Analysis of chromosome aberrations in mice with targeted deletion of Brca1 exon 2 and Trp53bp1. Left, metaphase spreads were prepared from B cells treated with olaparib. Arrows show examples of chromosome aberrations. Right, quantification of chromosome breaks (CSB), chromatid-type breaks (CTD), radial chromosomes, and other abnormalities in mouseB cells. Error bars indicate SD, N=3 