ZW sex-determination system
ZW sex-determination system is a method of sex determination in which organisms develop into males or females depending on the presence or absence of certain chromosomes. This system is used by many birds, some reptiles, and some insects. In this system, the sex of an individual is determined by the combination of sex chromosomes they receive from their parents.
Overview[edit | edit source]
In the ZW sex-determination system, the sex chromosomes are not homologous. This means that they do not pair and exchange genetic material during meiosis. Instead, one of the sex chromosomes, the Z chromosome, is larger and contains more genes, while the other, the W chromosome, is smaller and contains fewer genes.
Females have one Z and one W chromosome (ZW), while males have two Z chromosomes (ZZ). This is the opposite of the XY sex-determination system used by most mammals, where the male has two different kinds of sex chromosomes (XY) and the female has two of the same kind (XX).
Mechanism[edit | edit source]
The mechanism of the ZW sex-determination system is not fully understood. However, it is believed that the W chromosome carries a sex-determining gene that triggers the development of female characteristics. In the absence of a W chromosome, the individual develops as a male.
Evolution[edit | edit source]
The ZW sex-determination system is thought to have evolved independently several times. It is believed that the Z and W chromosomes originated from a pair of autosomes that acquired a sex-determining gene. Over time, the W chromosome has lost most of its genes and has become smaller than the Z chromosome.
See also[edit | edit source]
References[edit | edit source]
 | This anatomy article is a stub. You can help WikiMD by expanding it. |
Search WikiMD
Ad.Tired of being Overweight? Try W8MD's physician weight loss program.
Semaglutide (Ozempic / Wegovy and Tirzepatide (Mounjaro / Zepbound) available.
Advertise on WikiMD
|
WikiMD's Wellness Encyclopedia |
| Let Food Be Thy Medicine Medicine Thy Food - Hippocrates |
Translate this page: - East Asian
中文,
日本,
한국어,
South Asian
हिन्दी,
தமிழ்,
తెలుగు,
Urdu,
ಕನ್ನಡ,
Southeast Asian
Indonesian,
Vietnamese,
Thai,
မြန်မာဘာသာ,
বাংলা
European
español,
Deutsch,
français,
Greek,
português do Brasil,
polski,
română,
русский,
Nederlands,
norsk,
svenska,
suomi,
Italian
Middle Eastern & African
عربى,
Turkish,
Persian,
Hebrew,
Afrikaans,
isiZulu,
Kiswahili,
Other
Bulgarian,
Hungarian,
Czech,
Swedish,
മലയാളം,
मराठी,
ਪੰਜਾਬੀ,
ગુજરાતી,
Portuguese,
Ukrainian
Medical Disclaimer: WikiMD is not a substitute for professional medical advice. The information on WikiMD is provided as an information resource only, may be incorrect, outdated or misleading, and is not to be used or relied on for any diagnostic or treatment purposes. Please consult your health care provider before making any healthcare decisions or for guidance about a specific medical condition. WikiMD expressly disclaims responsibility, and shall have no liability, for any damages, loss, injury, or liability whatsoever suffered as a result of your reliance on the information contained in this site. By visiting this site you agree to the foregoing terms and conditions, which may from time to time be changed or supplemented by WikiMD. If you do not agree to the foregoing terms and conditions, you should not enter or use this site. See full disclaimer.
Credits:Most images are courtesy of Wikimedia commons, and templates Wikipedia, licensed under CC BY SA or similar.
Contributors: Prab R. Tumpati, MD
