What is Parthenogenesis- Complete Details

byAmlesh Mahato •June 10, 2020

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What is Parthenogenesis? Types, Process, Examples and Significance

Parthenogenesis Diagram — Parthenogenesis Process Diagram

What is Parthenogenesis?

Parthenogenesis is the development of a female gamete into an embryo without any contribution from the male gamete.

It is common in plants and occurs naturally in several insects, crustaceans and rotifers.

Induced Parthenogenesis

Artificial activation of eggs without fertilization is called induced parthenogenesis.

Sea urchin eggs can be induced by chemical treatment, electric shock or changes in sea-water conditions.

Stimulation of Induced Parthenogenesis

Physical Stimulus

Egg activation by mechanical injury.

Temperature Stimulus

Egg activation through temperature shock.

Chemical Stimulus

Activation using lactic acid, butyric acid, ether, acetone and other chemicals.

Sperm Entry Stimulus

Sperm triggers egg division without nuclear fusion.

Significance of Artificial Parthenogenesis

Acts as a means of reproduction.
Allows rapid multiplication.
Preserves advantageous gene combinations.
Eliminates harmful gene combinations through selection.
Reduces variation in offspring.

Natural / Obligatory Parthenogenesis

Natural parthenogenesis is a regular mode of reproduction in organisms such as honey bees.

Complete (Cyclic) Parthenogenesis

No sexual phase is present and reproduction occurs exclusively through parthenogenesis.

Incomplete (Non-Cyclic) Parthenogenesis

Sexual and parthenogenetic generations alternate.

Haploid Parthenogenesis

Unfertilized haploid eggs develop into haploid individuals, usually males.

Examples

Hymenoptera
Homoptera
Coleoptera
Thysanoptera

Diploid (Thelytokous) Parthenogenesis

Diploid chromosome number is restored and unfertilized eggs develop into diploid individuals.

Amitotic Parthenogenesis

First meiotic division is absent and eggs remain diploid.

Meiotic Parthenogenesis

Chromosome doubling occurs after meiosis resulting in diploid offspring.

Process of Diplosis

Auto Fertilization

Two products of meiosis fuse to restore diploidy.

Restitution

Karyokinesis occurs without cytokinesis, producing diploid eggs.

Frequently Asked Questions

What is parthenogenesis?

Development of an embryo from an unfertilized egg.

What is induced parthenogenesis?

Artificial activation of an egg without fertilization.

Which organism commonly shows parthenogenesis?

Honey bees, aphids, rotifers and some crustaceans.