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:"For other meanings see
Zygote (disambiguation)."A zygote (from Greek ζυγωτός "zugōtos" "joined" or "yoked", from ζυγοῦν "zugoun" "to join" or "to yoke") [cite web| url=http://www.myetymology.com/english/zygote.html |title=English etymology of zygote |publisher=myetymology.com] is a cell that is the result of fertilization. That is, two haploid cells—usually an ovumfrom a femaleand a spermcell from a male—merge into a single diploid cell called the "zygote" (or "zygocyte").
Variations in different species
Animal zygotes undergo mitotic
cell divisions to become a blastocystthen an embryo. A zygote has all of the DNArequired to grow into a fetusfor birth. Other organisms may undergo meiotic cell division at this time (for more information refer to biological life cycles).
mammals, fusion of the sperm with the ovacyte occurs in the fallopian tubeand the resulting diploid zygote becomes embedded in the uterine wall.cite web| url=http://www.umm.edu/ency/article/002398.htm| title=Fetal development |publisher=University of Maryland Medical Center] In humans, the blastocyst often reaches the uterus in five days. On the sixth day, the blastocyst implants itself into the uterine wall.
Twins and multiple births can be monozygotic (identical) or dizygotic (fraternal), meaning they arise from one or several (strictly, two) fertilization events. Polyspermic zygotes in mice have been manipulated so as to remove one of the two male pronuclei and made to survive birth. [cite web| url=http://www.ncbi.nlm.nih.gov/pubmed/8671222| title=Birth of normal mice after removal of the supernumerary male pronucleus from polyspermic zygotes |publisher=National Center for Biotechnology Information]
In other species
A biparental zygote is a
Chlamydomonas(a kind of algae) zygote that contains chloroplast DNA( cpDNA) from both parents.
Zygote intrafallopian transfer
* Twin Zygosity
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