Parthenogenesis (Virgin Birth)

The mode of reproduction in which a new individual develops from an unfertilized ovum without the participation of a sperm cell is called parthenogenesis.

An organism that develops from an unfertilized egg by parthenogenesis is called a parthenogenome or parthenote.

Parthenogenesis in animals was discovered by Charles Bonnet in 1745.

• Normally, an ovum develops into a new individual only after fertilization.
• In some cases, an unfertilized ovum also develops into an individual.
• This mode of sexual reproduction, in which development of the egg occurs without the participation of a sperm cell, is known as parthenogenesis.

Occurrence:

• Parthenogenesis is a naturally occurring phenomenon among insects.
• It also occurs in crustaceans, rotifers, some lizards, and platyhelminthes.
• It is rare in vertebrates.

Examples:

• In honey bee, the males called drones are produced parthenogenetically.
• In honey bee, the queen bee and worker bees develop from fertilized ova.
• Aphids lay eggs which hatch parthenogenetically into females.
• A breed of white turkeys was found to lay eggs that hatch without fertilization.
• Lacerta saxicola, the rock lizard, also shows parthenogenesis.
• Typhlina brahmina, a small Indian snake, also shows parthenogenesis.

• Parthenogenesis is the development from an unfertilized egg.
• Sperm cells do not participate in this process.
• Charles Bonnet discovered it in animals in 1745.
• It occurs naturally in insects, crustaceans, rotifers, some lizards, and platyhelminthes.
• It is rare in vertebrates.
• Honey bee is the standard example: drones arise from unfertilized eggs, while queen and workers arise from fertilized eggs.