A Penetrated Human Ovum studied by Electron Microscopy

Caenorhabditis eleganspolo-like kinase PLK-1 is required for merging parental genomes into a single nucleus

“…Broadly speaking, the association of the maternal and paternal pronuclei can happen in one of two ways ( Szabo and O’Day, 1983 ): the NEs of the two pronuclei can fuse (as is the case for nuclei of gametes in a variety of fungi, algae, and higher plants) or, once the two pronuclei are in close apposition, their NEs can break down, leading to the mixing of their contents. The latter mechanism is common in vertebrates such as mouse ( Zamboni et al , 1972 ) and human ( Zamboni et al , 1966 ), although it has been suggested that pronuclear fusion can take place in in vitro–fertilized human oocytes (see, e.g., Levron et al , 1995 ; van der Heijden et al , 2009 ). In the fish Oryzias ( Iwamatsu and Kobayashi, 2002 ) and in rabbit ( Gondos et al , 1972 ), nucleoplasmic bridges form between the two pronuclei before complete NE disassembly.…”

Is paternal mitochondrial DNA transferred to the offspring following intracytoplasmic sperm injection?

“…preembryos for morphological examination which had been flushed out of the fallopian tube in connection with an operative procedure has also been reported (2). Whether or not the whole midpiece and the sperm tail generally enters through the oolema and can move freely in the cytoplasm or remains in close connection with the oolema is thus partly an unsolved question.…”