Zygote
A diploid cell formed by fusion of two gametes.
It is the earliest developmental stage of a multicellular organism.[1] The zygote contains all the genetic information needed to become a baby.[2] A eukaryotic cell resulting from the union of two gametes during fertilization is called a zygote.[3]
Quick Facts
- Precursor
- Gametes
- Givesriseto
- Blastomeres
Facts from the source article.
Key facts and history
In humans, a haploid secondary oocyte and a haploid sperm combine to form a single diploid zygote.[4] After the sperm fuses with the oocyte, the oocyte completes the second meiosis, forming a haploid daughter with 23 chromosomes and the male pronucleus.[4] In 1875, Oscar Hertwig, a German zoologist, conducted pioneering research on zygote formation using sea urchins.[5] Hertwig demonstrated that a single sperm penetrates the egg, and subsequently the two pronuclei merge to create one nucleus.[5]
The second polar body, which contains chromosomes but lacks the capacity for replication or survival, is the other product of meiosis.[4] Replication of DNA occurs within the two distinct pronuclei, which temporarily results in the zygote having a 4n diploid chromosome count.[4] While moving through the fallopian tube toward the uterus, the conceptus undergoes cleavage, a process of division without overall growth.[6] When fertilization involves gametes that have not undergone meiotic reduction, the resulting plant zygote can be polyploid.[7]
What the cited sources add
The MedlinePlus Medical Encyclopedia states that the zygote spends the next few days traveling down the fallopian tube.[2] A 2015 report from Sun Yat-sen University described scientists editing a gene in fertilized human eggs called zygotes.[8] One group called for scientists to agree not to modify the DNA of human reproductive cells, including the nonviable zygotes used in that study.[8] The zygotes used in those experiments could not develop into a person because they had three sets of chromosomes, having been fertilized by two sperm in lab dishes.[8]
References
- Wikipedia, "Zygote" (CC BY-SA 4.0), which cites: Khan, "Embryology, Week 1", StatPearls, 2025 (original not read by us) en.wikipedia.org
- O'Reilly, Deirdre. "Fetal development ". MedlinePlus Medical Encyclopedia (2007-10-19). Retrieved 2009-02-15.. facts only, no text reused. medlineplus.gov
- Wikipedia, "Zygote" (CC BY-SA 4.0), which cites: "English etymology of zygote", etymonline.com (we also read that source) en.wikipedia.org
- Wikipedia, "Zygote" (CC BY-SA 4.0), which cites: Blastomere Encyclopædia Britannica . Encyclopædia Britannica Online. Encyclopædia Britannica Inc., 2012. Web. 06 Feb. 2012. (original not read by us) en.wikipedia.org
- Wikipedia, "Zygote" (CC BY-SA 4.0), which cites: Malkin, "The 19th-century elucidation of animal fertilization: Its relation to the cell theory, embryology, and cytogenetics.", muse.jhu.edu, 1998; Malkin, "The 19th-century elucidation of animal fertilization: Its relation to the cell theory, embryology, and cytogenetics.", muse.jhu.edu, 1998; Malkin, "The 19th-century elucidation of animal fertilization: Its relation to the cell theory, embryology, and cytogenetics.", muse.jhu.edu, 1998 (original not read by us) en.wikipedia.org
- Wikipedia, "Zygote" (CC BY-SA 4.0), which cites: O'Reilly, Deirdre. "Fetal development ". MedlinePlus Medical Encyclopedia (2007-10-19). Retrieved 2009-02-15.; Klossner, N. Jayne and Hatfield, Nancy. Introductory Maternity & Pediatric Nursing, p. 107 (Lippincott Williams & Wilkins, 2006).; Neas, John F. "Human Development" . Embryology Atlas; Blackburn, Susan. Maternal, Fetal, & Neonatal Physiology, p. 80 (Elsevier Health Sciences 2007). (we also read that source) en.wikipedia.org
- Wikipedia, "Zygote" (CC BY-SA 4.0), which cites: Brownfield, "Unreduced gamete formation in plants: mechanisms and prospects", Journal of Experimental Botany, 2011-03-01, p. 1659–1668 (original not read by us) en.wikipedia.org
- "Editing human germline cells sparks ethics debate", May 6, 2015. facts only, no text reused. sciencenews.org
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Zygote (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
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