Telomere length in MII oocytes during female and postovulatory aging. (A) Telomere Q-FISH images of oocytes. Blue: DAPI-stained chromosomes, Yellow: telomeres. (B) Frequency distributions of telomere fluorescence in metaphase spreads of fresh oocytes from young females (telomere numbers = 695), fresh oocytes from reproductively-aged females (telomere numbers = 576), in vivo-aged (telomere numbers = 244), and in vitro-aged (telomere numbers = 444) oocytes. Blue lines in the histograms indicate medians of the distribution. Yellow lines show means (N: total number of oocytes). (C) Relative telomere length shown as the T/S ratio by qPCR analysis. The error bars show mean ± SEM. *P < 0.05 (n: represents number of replicated experiments).