Changes

* Male and female pronuclei fuse.

* Male and female pronuclei fuse.

* Sperm delivers a haploid complement of chromosomes, but also activates the Oocyte by:  

* Sperm delivers a haploid complement of chromosomes, but also activates the Oocyte by:  

** A unique '''phospholipase Cζ''' causes release of calcium from the endoplasmic reticulem to the cytosol.  This is then re-sequestered and bound in the endoplasmic reticulem to give regular 'spikes' or oscillations of calcium that signal rapidly across the Oocyte.  The calcium signal activates the Oocyte from meiotic arrest.

** A unique '''phospholipase Cζ (zeta)''' causes release of calcium from the endoplasmic reticulem to the cytosol.  This is then re-sequestered and bound in the endoplasmic reticulem to give regular 'spikes' or oscillations of calcium that signal rapidly across the Oocyte.  The calcium signal activates the Oocyte from meiotic arrest.

** Provides the '''centriole''' contribution to initial cell division, allowing formation of the two-celled embryo.

** Provides the '''centriole''' contribution to initial cell division, allowing formation of the two-celled embryo.

''N.B: Although sperm mitochondria enters the Ooctye cytoplasm, they carry a ubiquitin signal.  They are subsequently destroyed by Ubiquiitinase and do NOT contribute to mitochondrial DNA.  Therefore mitochondial DNA is entirely from the maternal side.''

''N.B: Although sperm mitochondria enters the Ooctye cytoplasm, they carry a ubiquitin signal.  They are subsequently destroyed by Ubiquiitinase and do NOT contribute to mitochondrial DNA.  Therefore mitochondial DNA is entirely from the maternal side.''