Telomere length analysis. (A) Assessment of telomere length in WT or Smc1β−/− spermatocytes. Southern blotting and ethidium bromide (EtBr)–stained gel for loading control of Smc1β+/− testis DNA (Het) and Smc1β−/− testis DNA (KO). m, DIG-labeled marker; M, pulsed field gel electrophoresis low-range marker. Bars indicate the length of the telomere signal smear. (B) Quantitative telo-FISH of zygotene or pachytene spermatocyte spreads such as those shown in Figs. 6 and 7 using ImageJ software. (C) Box and whiskers plot to visualize median lengths (−) and maximum range (+). The intervals containing the median 50% of telomere intensity values are boxed (7.8–22.5 fluorescence telomere intensity units [F-TIU]).