Bayer and colleagues describe the first paternal effect on plant embryogenesis, and show that the timing of zygote elongation and the first division are mediated by a signal provided by the sperm ...

The fusion of sperm and egg gametes during human fertilization establishes a diploid zygote and initiates a series of cell divisions that result in a multicellular embryo. The blastocyst stage is ...

It can last anytime between 36 and 42 weeks after fertilization and still be considered a normal timeframe. An egg becomes fertilized when a sperm penetrates it, creating a zygote. For the first ...

The facility is fully equipped for microinjections, microsurgery, zygote electroporation, gene targeting and tissue culture ... rederivation for the importation or “clean-up” of infected mice or rats; ...