The Clock mutation reduces reproductive performance of mice by affecting the implantation capacity: Maternal Clock mutation is not the only factor affecting implantation

Here, we showed that the Clock gene was important for reproductive performance in mice. We compared outcomes from the four possible mating combinations between wild-type mice (WT) and mice homozygous for the Clock delta-19 mutation (CL). We found that the only significant differences were between the WT♂ × WT♀ and CL♂ × CL♀ mating groups; these groups differed with regard to elongation of the pregnancy period (19.3 vs. 20.5 days, respectively, P CL♂ × CL♀), suggesting that the Clock mutation reduced the reproduction performance of the parents by affecting the implantation capacity via such as embryos' ability to implant.