Meiotic recombination, synapsis, meiotic inactivation and sperm aneuploidy in a chromosome 1 inversion carrier  Gordon Kirkpatrick, Victor Chow, Sai Ma  Reproductive BioMedicine Online  Volume 24, Issue 1, Pages 91-100 (January 2012) DOI: 10.1016/j.rbmo.2011.09.013 Copyright © 2011 Reproductive Healthcare Ltd. Terms and Conditions

Figure 1 Karyotype of chromosome 1 and the inverted der(1) chromosome. Idiogram and karyotypes of chromosome 1 and the inverted chromosome, with arrows at the location of the breakpoints at p21 and q31. Reproductive BioMedicine Online 2012 24, 91-100DOI: (10.1016/j.rbmo.2011.09.013) Copyright © 2011 Reproductive Healthcare Ltd. Terms and Conditions

Figure 2 Immunofluorescent and fluorescent in-situ hybridization (FISH) analysis of pachytene nuclei of control spermatocytes. (A) Spermatocytes immunolabelled to visualize SCYP1 (axial elements of synaptonemal complex) and SCYP3 (lateral elements of synaptonemal complex) in red, MLH1 (foci of recombination) in green and centromeres in blue. (B) Pachytene nuclei that displayed an absence of recombination in the sex body (box) were noted. (C) Synaptic errors were observed that included gaps (boxes), in which there was loss of both SYCP1 and SYCP3 staining (upper box), an asynapsis, in which there was loss of only SYCP1 staining (lower box). (D) Nuclei were also noted in which there was an absence of recombination on an autosomal bivalent (box). (E,F) The identity of chromosomes 13, 18 and 21 was determined with FISH following immunostaining (F) to examine synapsis and recombination on chromosomes 13 (green signal), 18 (blue signal) and 21 (red signal). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.) Reproductive BioMedicine Online 2012 24, 91-100DOI: (10.1016/j.rbmo.2011.09.013) Copyright © 2011 Reproductive Healthcare Ltd. Terms and Conditions

Figure 3 Immunostaining and fluorescent in-situ hybridization (FISH) analysis of the inv(1) carrier. (A,B,C) Spermatocytes from the inv(1) carrier were immunolabelled to visualize SCYP1 (axial elements of synaptonemal complex) and SCYP3 (lateral elements of synaptonemal complex) in red, MLH1 (foci of recombination) in green and centromeres in blue. (A′,B′,C′) FISH following immunolabelling for chromosome arm 1q (green), chromosome arm 1p (red) and the X and Y chromosomes (blue) was performed to locate the inverted chromosome and the sex body. (A″,B″,C″) Lastly, cells were immunolabelled with antibodies for markers of meiotic silencing γH2AX (red) and BRCA1 (green). Inverted chromosomes displaying asynapsis, displayed localization of BRCA1 (green), γH2AX (red) and XY FISH probe (blue) both when associated with the sex chromosomes (A″) and when not (C″). Inverted chromosomes that displayed heterosynapsis (B) displayed no localization of BRCA1 and γH2AX (B″). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.) Reproductive BioMedicine Online 2012 24, 91-100DOI: (10.1016/j.rbmo.2011.09.013) Copyright © 2011 Reproductive Healthcare Ltd. Terms and Conditions

Figure 4 Asynapsis and meiotic inactivation. Inverted chromosomes, located with immunolabelling for SCP1 and SCP3 (red), MLH1 (green) and centromeres (blue) (A,B) and with probes for chromosome 1p telomere (red) and chromosome 1q telomere (green) (A′,B′), displayed asynapsis (A–A″) (boxes) as well as heterosynapsis (B–B″). Asynapsed inversions showed evidence of meiotic inactivation (A″) observed by staining with BRCA1 (green) and γH2AX (red) in both the XY body and the asynapsed region of the inversion. Inversions undergoing heterosynapsis displayed meiotic inactivation of the XY body (B″) although there was no evidence of meiotic inactivation in the inverted chromosome. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.) Reproductive BioMedicine Online 2012 24, 91-100DOI: (10.1016/j.rbmo.2011.09.013) Copyright © 2011 Reproductive Healthcare Ltd. Terms and Conditions