Meiosis errors in over 20,000 oocytes studied in the practice of preimplantation aneuploidy testing  Anver Kuliev, Zev Zlatopolsky, Irina Kirillova, Julia Spivakova, Jeanine Cieslak Janzen  Reproductive BioMedicine Online  Volume 22, Issue 1, Pages 2-8 (January 2011) DOI: 10.1016/j.rbmo.2010.08.014 Copyright © 2010 Reproductive Healthcare Ltd. Terms and Conditions

Figure 1 Aneuploid oocytes in relation to maternal age, predicted by PB1 and PB2 testing for chromosomes 13, 16, 18, 21 and 22. Number of oocytes tested for each age group is shown under the curve, which shows the increase of the overall frequency from 20% in the age group 35 years to close to 60% in the age group 43 years and over. Reproductive BioMedicine Online 2011 22, 2-8DOI: (10.1016/j.rbmo.2010.08.014) Copyright © 2010 Reproductive Healthcare Ltd. Terms and Conditions

Figure 2 Proportions of chromosome (chromatid) segregation errors in meiosis I. Upper panel: Centre: primary oocyte containing diploid set of chromosomes with the doubled amount of chromatin (4n) prior to maturation; Right: normal segregation of homologues in the first meiotic division, resulting in the extrusion of the first polar body (PB1) (smaller circle) containing one of the homologues; accordingly, the resulting secondary (metaphase II) oocyte contains the remaining homologue with two chromatids; Left: meiotic errors leading to the extrusion of PB1 containing abnormal set of chromosomes. Lower panel: (a) chromosomal non-disjunction, leading to segregation of both homologues to MII oocyte so that the extruded PB1 does not contain any material, results in a disomic oocyte; (b) chromosomal non-disjunction, leading to segregation of both homologues to PB1(smaller circle), which results in a nullisomic oocyte; (c) chromatid malsegregation, leading to an extra chromatid extrusion with PB1, which results in the lack of one chromatid in MII oocyte; (d) chromatid malsegregation, leading to a single chromatid extrusion with PB1, which results in the extra chromatid material in MII oocyte; (e) chromatid or chromosome malsegregation involving different chromosomes, involving different types of errors of different chromatids or chromosomes in MII oocyte, which results in complex errors. Reproductive BioMedicine Online 2011 22, 2-8DOI: (10.1016/j.rbmo.2010.08.014) Copyright © 2010 Reproductive Healthcare Ltd. Terms and Conditions