SUV39H1 and Infertility: The decrease in progeny viability for the ΔEZL3 cells missing H3K23me3 is also similar in scope to reported infertility and increased spermatocyte apoptosis in male mice missing both copies of the H3K9me3 methyltransferases, Suv39h1/2 (Figure 6E) (Peters et al., 2001).