JCS03394 Supplementary Material

Files in this Data Supplement:

• Supplemental Figure 1 -

  Fig. S1. Numbers and distribution of RAD51/DMC1 foci at leptotene before synapsis of chromosome cores. The foci were visualized with antibodies to RAD51/DMC1 proteins but since they would also have RPA at this stage, they are classified as TNs. (A) Gamma distribution of the distances, in μm, between 100 foci along unpaired cores. The data fit reasonably well to a gamma distribution of shape 2.97, standard error 0.40, indicating a fairly even rather than a random distribution. (B) The results are similar if the distances are expressed as percentages of the distances between the proximal and distal focus. (C) Simulation of 500 EN/TNs along an unpaired core distributed according to a gamma shape of 2.97. (D) Simulation of the distances between foci if two such cores undergo synapsis. As a result, the distribution of foci would be close to random and have a poor fit to the gamma of 1.65. Since the observed distribution of foci following synapsis is, to the contrary, very even, it follows that some form of regulation reduces the number of foci and generates an even distribution.

• Supplemental Figure 2 -

  Fig. S2. TNs at pachytene synaptonemal complexes. (A) Cell 08 (see Fig. S3C) has 215 TN foci that are distributed among the SCs proportional to their lengths (see Fig. S3D). The TNs are evenly spaced along the SCs, shape=4.2, but the fit to the gamma distribution is poor, P=0.004. (B) When the distribution is expressed as a percentage of SC length, the goodness of fit improves, P=0.10. (C) A late zygotene nucleus from which the data for this figure were obtained. SCs and centromeres, green; foci, red. (D,E) Combining distances from short or long SCs, respectively, gives similar results.

• Supplemental Figure 3 -

  Fig. S3. Distances between 140 TNs from cell 02 that is somewhat more advanced than cell 08. (A) Distances in micrometers can be fitted to a gamma distribution of 3.8 with a goodness of fit P=0.025. (B) Distances as a percentage of SC lengths give a better fit, P=0.145. (C,D) There is a linear relationship between numbers of foci per SC versus SC length for cell 02 and 08 (D). For cell 02, the quadratic term is not significant t=−1.03, Pr(>I t I) 0.32, not significant, and for cell 08, the quadratic term is marginally not significant. Thus, the data from all SCs can be pooled.

• Supplemental Figure 4 -

  Fig. S4. Spermatocytes deficient for histone H2AX have defective spermatocytes, but the reasonably well organized nuclei appear to have less than normal numbers of TNs. (A) An example of an H2ax^−/− spermatocyte nucleus with well defined SCs, but few TNs (140). (B) Even in the absence of histone H2AX, the TNs are relatively evenly distributed, well fitted (P=0.48) to a gamma distribution, with shape of 2.3. (C) The results are similar when the measurements are expressed as percentages of SC lengths.

• Supplemental Figure 5 -

  Fig. S5. At late meiotic prophase the few remaining TNs are distributed randomly along the SCs. (A) Distribution of distances between 32 autosomal TNs. The shape of the gamma distribution is not significantly different from 1 suggesting a random distribution. (B) The distances between TNs from five nuclei with few TNs (46, 40, 37, 34, and 27) can be fitted to gamma distribution of shape=1, also indicating that the removal of TNs did not follow a systematic pattern.