Fig. 2: Recombination in mutant spermatocytes.

a MLH1 immunolocalization in spermatocyte nuclei. Shown are pachytene spermatocyte chromosome surface spreads from 6 month old males, immunolabeled with SYCP3 (red) and MLH1 (green). White arrows indicate MLH1. Note weak and nearly absent staining in the mutants. b MLH1 focus quantification in spermatocytes. *p-value <0.0001. Others do not have p-values < 0.05 for decreased foci. Over 30 cells from at least 3 animals were quantified, except for Mlh3^R1230H, where 27 cells from two animals were scored. c Violin plots illustrating the chromosome pairs in a spermatocyte nucleus lacking an MLH1 focus. White circles show the medians; box limits indicate the 25th and 75th percentiles; whiskers extend 1.5 times the interquartile range from the 25th and 75th percentiles; polygons represent density estimates of data and extend to extreme values. For mutants with more MLH-deficient pairs, *p-value <0.0001 unless otherwise indicated; comparisons to WT with p-values >0.05 are not shown. d Example of spermatocyte metaphase spread from the Mlh1^K618T mutant and control. e Quantification of chiasmata and bivalents in Mlh1^K618T and WT. Twenty or more cells from three animals were analyzed. Scale Bar = 5 μm. Data in b and e are plotted as follows: Boxes indicate data points between the first and third quartiles of the distribution, whiskers show minimum and maximum values, black horizontal lines and ‘+’ sign indicate the median and mean values respectively. Data in b, c and e were analyzed using Unpaired Student’s t-test from the total number of spermatocytes (shown as ‘n’) from multiple animals indicated as ‘N’.