Figure 5. Chromosome abnormalities are increased in cohesin heterozygotes.

Representative images of numerical and structural defects in cohesin heterozygotes. (A) Premature sister chromatid separation in MII eggs; arrows denote the unattached single chromatids. (B) Anaphase bridges between MII eggs and first polar bodies. (C) Chromatid defects in MII eggs; arrows denote abnormal chromatid. (Left) acentric fragment; (middle) deletion of almost an entire chromatid; (right) proximal chromatid break; note that acentric fragment remains attached to telomere of intact sister chromatid. (D) Defects in diakinesis stage oocytes: (left) bivalent with a chromatid break in one chromosome; (middle) nonhomologous end-to-end chromosome fusion that appears to involve both chromatids of two bivalents; (right) proximal break in a single chromatid.