PLCζ1 is not essential for in vivo fertilization. (a) Fecundity of Plcz1 heterozygous and KO males. The horizontal line and numerals indicate the mean numbers of pups/vaginal plug noted. (b) Oocytes collected from oviducts of females mated with Plcz1 KO males at 10 h post coitus. Oocytes with various numbers of pronuclei were observed. Arrow and dotted circles represent the fertilizing cone and pronuclei, respectively. Scale bar = 20 μm. (c) The percentages of oocytes with the numbers of PN at 12 h post coitus.