The first diploid cell that forms following fertilization by fusion of the haploid oocyte (egg) and spermatozoa (sperm) resulting in the combination of their separate genomes. The first image shows the cell with the 2 pronuclei still present before fusion enclosed within the zona pellucida. In humans, this cell then undergoes a series of mitotic cell divisions, still enclosed within the zona pellucida, during the first few days of development to form 2 blastomeres then a solid cell mass called the morula.
Some Recent Findings
Human Zygote Size
Animation based upon individual images of mouse maternal and paternal genomes.
|Quicktime | Flash|
Mouse zygote pronuclei
Most ribosomal DNA located around the Nucleolar-Precursor Bodies (NPBs), with some associated with pericentromeric filaments (extending from the NPBs towards the nuclear periphery) as well as rDNA signals joining two NPBs.
Formation of Zygote
- male and female pronuclei, 2 nuclei approach each other and nuclear membranes break down
- DNA replicates, first mitotic division
- sperm contributes centriole which organizes mitotic spindle
Conceptus - term refers to all material derived from this fertilized zygote and includes both the embryo and the non-embryonic tissues (placenta, fetal membranes).
Zygote Protein Expression
The table above shows the pattern of protein expression (as percentages of total) in the mouse zygote according to 14 molecular function categories.
- Links: Germinal vesicle oocyte protein expression | MII oocyte protein expression | Zygote Protein Expression | Mouse Development | Oocyte Development | Zygote
Male Pronucleus Reprogramming
|Mouse zygote paternal genome reprogramming
Mouse zygotes male pronucleus contains 5-hydroxymethylcytosine (5hmC) thought to be formed by enzymatic oxidation of 5-methylcytosine (5mC).
Mouse zygote mitosis
- Zygote An international journal dedicated to the rapid publication of original research in early embryology, Zygote covers interdisciplinary studies in animals and humans, from gametogenesis through fertilization to gastrulation.
June 2010 "zygote" All (6213) Review (651) Free Full Text (1543)
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Cite this page: Hill, M.A. (2021, January 20) Embryology Zygote. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Zygote
- © Dr Mark Hill 2021, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G