Dictionary > Thelytoky

Thelytoky

Definition
noun
A form of parthenogenesis wherein female offspring develops from an unfertilized egg
Supplement
Parthenogenesis is regarded as a form of asexual reproduction. The offspring develops from an unfertilized egg. Parthenogenesis may be classified based on the sex of the offspring: (1) arrhenotokous parthenogenesis (or arrhenotoky), (2) thelytokous parthenogenesis (or thelytoky), and (3) deuterotokous parthenogenesis (deuterotoky).

The arrhenotoky is a form of parthenogenesis in which the unfertilized eggs develop into males. In contrast, thelytoky is a form of parthenogenesis in which unfertilized eggs develop into females. Deuterotokous parthenogenesis (deuterotoky) is one in which the unfertilized eggs may develop into males and females. Thelytoky occurs in invertebrates (e.g. arthropods) but less common in vertebrates. Some vertebrates that are capable of thelytoky include certain salamanders, fish, and reptiles (i.e. some whiptail lizards).

Automictic parthenogenesis is a form of thelytoky. Automictic parthenogenesis is characterized by the involvement of meiotic division in contrast to apomictic parthenogenesis that does not involve meiosis. Since meiosis takes place in automictic parthenogenesis, the egg is haploid. Diploidy in egg is restored by fusion, which may be by central fusion (i.e. the fusion of the first division non-sister nuclei) or by terminal fusion (i.e. the fusion of the second division sister nuclei).
Word origin: Greek thēlys (“female” ) + tók(os) (“offspring”)
Also called:

  • thelytokous parthenogenesis

Compare:

See also:


You will also like...

Hominid
The Hominids

The hominid family diversified from the apes around 6 to 8 million years ago. Since then, the evolutionary path has prov..

Biological Viruses
Biological Viruses

Viruses possess both living and non-living characteristics. This unique feature distinguishes them from other organisms...

takahē
Takahē (Porphyrio hochstetteri)

Meet the colorful takahē, an extremely rare flightless bird. Find out more about its unique features and why they matte..

Schematic diagram of bacterial lactose operon
Gene Action – Operon Hypothesis

Learn how the way genes control and determine every aspect of the body. This lesson uses lac operon as an example. ..

..

Growth Patterns
Growth Patterns

This tutorial describes the sigmoid curve, annual plant growth, tree growth, human growth, and insect growth as the grow..

An artistic depiction of Dunkleosteus fish
Fish

The sea was teeming with life. Eventually, through reproduction and continued variation, fish came about. There are over..

Related Articles...

No related articles found

See all Related Topics