Tables S6 & S7). The frequency of NR Diplos (NR/N where N is total progeny) is similar for all four sub-broods that arise from non- aged oocytes (0.72,P,0.76 for pair-wise comparisons). Non- recombinant chromosomes in aged oocytes missegregate more frequently in sub-broods 3, 4 and 6 than in sub-brood 1, although this difference is not statistically significant (0.10,P,0.27). However, a comparison of sub-brood 3 aged and non-aged oocytes shows that aging causes a significant increase in the frequency at which non-recombinant chromosomes missegregate (P = 0.029). These data reinforce the model that the achiasmate chromosome segregation pathway is vulnerable to age effects and that sister-chromatid cohesion proteins play a role in this process (see Discussion). Found at: doi:10.1371/journal.pgen.1000263.s002 (0.18 MB TIF) X chromosome nondisjunction in smc1+/2 and mtrm+/2 Table S1 oocytes (no aging regimen). Found at: doi:10.1371/journal.pgen.1000263.s003 (0.03 MB DOC) Table S2 Higher meiotic missegregation is not observed in smc1+/2 aged oocytes when the achiasmate pathway is functional. Found at: doi:10.1371/journal.pgen.1000263.s004 (0.03 MB DOC) Table S3 Age-dependent segregation errors arise in smc1+/2 oocytes when achiasmate segregation also is disrupted. Found at: doi:10.1371/journal.pgen.1000263.s005 (0.07 MB DOC) Table S4 Segregation errors do not increase with age when the achiasmate pathway is compromised but cohesion is wild type. Found at: doi:10.1371/journal.pgen.1000263.s006 (0.04 MB DOC) References 1. Hassold T, Hunt P (2001) To err (meiotically) is human: the genesis of human aneuploidy. Nature Rev Genet 2: 280–291. 2. Hunt PA, Hassold TJ (2002) Sex matters in meiosis. Science 296: 2181–2183. 3. Hassold T, Chiu D (1985) Maternal age-specific rates of numerical chromosome abnormalities with special reference to trisomy. Hum Genet 70: 11–17. 4. 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Dernburg AF, Sedat JW, Hawley RS (1996) Direct evidence of a role for heterochromatin in meiotic chromosome segregation. Cell 86: 135–146. PLoS Genetics | www.plosgenetics.org 11 November 2008 | Volume 4 | Issue 11 | e1000263