Parthenogenesis: Types and Importance of Parthenogenesis

Parthenogenesis refers to the development of a female gamete without any fertilization. It is a type of asexual reproduction in which females do not require a male partner for fertilization and can produce gametes without them. This type of fertilization is seen in many types of insects. Insects like bees; wasps etc. do not have sex chromosomes and reproduce through parthenogenesis. Some plants and reptiles also reproduce through parthenogenesis. In this article, we will discuss the mechanism, types, and importance of parthenogenesis.

Key Takeaways: Parthenogenesis, Gamete, Fertilization, Chromosomes, Haploid, Diploid, Organisms, Sex Determination

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Mechanism of Parthenogenesis

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Parthenogenesis can be considered as a type of asexual reproduction in which the resultant offspring are produced without any fertilization. Offsprings are generally produced from gametes or sex cells as a result of meiosis. Generally, there are two types of cells found: haploid and diploid. Haploid cells contain a single set of chromosomes. Haploid adults are produced through haploid parthenogenesis, in which the offspring consists of a single set of chromosomes.

Diploid parthenogenesis can occur in two ways: automixis and apomixis.

• Automixis: In this type of parthenogenesis, the haploid cell either duplicates itself or pairs with another haploid cell to form a diploid zygote
• Apomixis: In this type of parthenogenesis, the parent cell produces two genetically identical diploid egg cells by mitosis which develops into diploid offspring.

Read More: Female Reproductive System

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Types of Parthenogenesis

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Parthenogenesis can be divided into two types depending upon the way they occur. They can be classified as:

• Natural Parthenogenesis
• Artificial Parthenogenesis

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Natural Parthenogenesis

Parthenogenesis occurs naturally in many organisms and is a regular and constant process. This type of parthenogenesis is termed natural parthenogenesis. Further natural parthenogenesis can be classified into two types:

• Complete parthenogenesis: In this process, the organisms depend upon self-reproduction due to the absence of the sexual phase or male partners.
• Incomplete parthenogenesis: This type of parthenogenesis occurs when the life cycle of the organism has two generations. One of the generations is sexual and the other is parthenogenetic generation.

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Artificial Parthenogenesis

The onset of parthenogenesis due to external factors like chemical and physical factors is called artificial parthenogenesis.

The factors that trigger parthenogenesis can be divided into two types: Physical factors and Chemical factors.

Physical Factors

The physical factors that trigger parthenogenesis are as follows:

• Parthenogenesis due to rise in temperature
• Ultraviolet light can also trigger parthenogenesis
• Electric shock waves
• Sometimes external stimuli like pricking can trigger parthenogenesis
• Chemicals can also trigger parthenogenesis in organisms. Some chemicals that can trigger parthenogenesis are acids, urea, fat solvents, chloroform, chlorides, etc.

Read More: Genes

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Importance of Parthenogenesis

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Parthenogenesis is not only a type of reproduction it also has other importance. Some of the importance of parthenogenesis is as follows:

• There are chances that mutant characters can develop in the offspring. These characters can be advantageous
• The number of offspring produced in this process is large which is difficult through sexual reproduction
• Parthenogenesis acts as an adaptation strategy when the environmental conditions are not suitable and sexual reproduction is difficult
• Parthenogenesis ensures the continuation of species when the male population is scarce or extinct
• It is a simple process and is very easy
• It supports the theory of inheritance which proves that chromosomes are the means of heredity
• Through parthenogenesis, organisms can have more than two sets of chromosomes.
• Parthenogenesis is the sex determination mechanism in insects like wasps, bees, etc.

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Things to Remember

• Parthenogenesis is the process of asexual reproduction in which female gametes develop without any fertilization
• Parthenogenesis can be either haploid parthenogenesis or diploid parthenogenesis, depending upon the cells involved
• Parthenogenesis can be induced either due to natural factors or artificial factors. Some physical factors that induce parthenogenesis include shock waves, ultraviolet rays, rise in temperature, etc.
• Parthenogenesis can also be induced by chemicals. Some chemicals that induce parthenogenesis are chloroform, chlorides, acids, urea, fat solvents, etc.
• Parthenogenesis has much other importance like mutation, adaptive strategy to the external environment; the number of offspring produced is large, sex determination mechanism in insects, etc.

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