Parthenogenesis: Definition, Types, Facts, Introduction, Significance, Topics

Edited By Irshad Anwar | Updated on Jul 02, 2025 07:07 PM IST

Parthenogenesis is a type of asexual form of reproduction. The organism is reproduced without a fertilisation process. In this Asexual Method, an unfertilized egg is developed into an embryo.This type of reproduction is seen in a wide range of organisms,from plants, insects, and reptiles to even some fish. The word ‘Parthenogenesis’ is derived from the Greek word ‘parthenos,’ meaning virgin, and ‘genesis,’ meaning creation which means a virgin creation in Biology.

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What Is Parthenogenesis?
Types Of Parthenogenesis
Mechanisms Of Parthenogenesis
Examples Of Parthenogenesis
Advantages Of Parthenogenesis
Disadvantages Of Parthenogenesis
MCQS on Parthenogenesis
Recommended video on Parthenogenesis

Parthenogenesis: Definition, Types, Facts, Introduction, Significance, Topics

Parthenogenesis is very rare in the Mammalia subphylum reproduction. In the process, the female produces offspring without the involvement of a male or sperm cell. This form of reproduction plays a significant role in nature, evolution, and genetic diversity. This article includes parthenogenesis, its types, Examples of Parthenogenesis with advantages and disadvantages of parthenogenesis.

What Is Parthenogenesis?

Parthenogenesis refers to the kind of reproduction in which the development of offspring occurs from an unfertilized egg. With this process, one is in a position to come up with offspring without the involvement of male gametes. All the offspring resulting from parthenogenesis are genetically identical to the parent. This occurs in different species of the animal and plant kingdom, and it has its associated advantages as well as disadvantages.

Features Of Parthenogenesis

Asexual Reproduction: Parthenogenesis is a kind of asexual reproduction since it doesn't include the fusion of male and female gametes.
Genetic Uniformity: All the progeny achieved through parthenogenesis are similar to the mother and are genetically identical. Parthenogenesis occurs in many organisms, including some insects like aphids, reptiles like certain lizards, and plants.
Environmental Triggers: Parthenogenesis can also be induced by environmental cues, such as the absence of males or adverse conditions for fertilisation.

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Types Of Parthenogenesis

There are several types of parthenogenesis: obligate parthenogenesis, wherein it is the only way of reproduction; and facultative parthenogenesis, wherein it may happen in the absence of males, but sexual reproduction is also possible. Types of Parthenogenesis Parthenogenesis can be broadly classified into many types based on the involved mechanisms.

1. Obligate Parthenogenesis

In obligate parthenogenesis, the species only reproduces through parthenogenesis; there is no sexual reproduction. This happens in specific aphid species and some reptiles.

2. Facultative Parthenogenesis

In facultative parthenogenesis, a population can reproduce both sexually and asexually. For example, some female lizards can reproduce through parthenogenesis when males are absent.

3. Cyclic Parthenogenesis

Cyclic parthenogenesis refers to the alternating production of sexual and asexual offspring depending on environmental conditions. This can be explained by some species of aphids that reproduce sexually when conditions are favourable and then switch to parthenogenesis when the going gets hostile.

Mechanisms Of Parthenogenesis

Parthenogenesis can occur through different biological mechanisms that determine whether the offspring are clones or have some genetic variation. Parthenogenesis may result from several mechanisms, which include the following:

Automixis

In automixis, the egg undergoes a meiosis process, but some of the cells fuse to restore the diploid state. It could donate some degree of genetic diversity to its offspring.

Apomixis

Apomixis is when an embryo develops directly from the egg cell without stages of meiosis. Offspring produced are identical to their mother's characteristics.

Examples Of Parthenogenesis

Parthenogenesis is seen in many living organisms, like insects, reptiles, and plants. In these organisms, females can produce offspring without fertilisation. This helps them reproduce quickly and survive in harsh conditions. Below are some common examples of parthenogenesis in nature.

Insects- Parthenogenesis is common in many insects, as in aphids and some species of bees. For instance, the females of aphids give rise to offspring without mating, and the populations exhibit high growth rates.

Reptiles- Some reptiles, such as the Komodo dragon and the whip-tailed lizards, have parthenogenesis, where females produce healthy offspring without the participation of males.

Plants- Some angiosperms, such as dandelions and some species of ferns, can naturally develop seeds without fertilisation through parthenogenesis.

Advantages Of Parthenogenesis

Parthenogenesis has many advantages for survival and growth. It helps organisms reproduce quickly and without needing a mate. Some of the advantages are given below:

Rapid Population Growth: It can bring about an increase in population quickly when males are lacking in a particular environment.

Genetic Uniformity: The daughter organisms that emerge are more or less genetically identical to the mother, thus ensuring that positive traits that have developed get passed on.

Independence from Mates: Parthenogenesis is a means of reproduction without males and, in very adverse or isolated conditions, may be useful.

Disadvantages Of Parthenogenesis

Parthenogenesis has some drawbacks. It reduces genetic variety, which can make it hard for organisms to survive changes in the environment. Below are some disadvantages given:

Lack of Genetic Diversity: Offspring formed will have almost similar genetic material, making them be affected almost similarly by various diseases or changes in the environment.

Adaptability: Since the offspring produced are genetically similar; therefore, the population may face difficulty adapting to changes in the environment.

Inbreeding Potential: Since parthenogenesis occurs in some populations in the total absence of sexuality, inbreeding is possible, reducing general fitness.

MCQS on Parthenogenesis

Question 1: In some plants, the female gamete develops into embryo without fertilization. This phenomenon is known as:

Autogamy
Parthenocarpy
Syngamy
Parthenogenesis

Answer: When female gamete does not undergo fertilisation and gets developed into embryo the process is called parhenogenesis.It occurs in some plants and many animals.

E.g., rotifers, honeybees, and even some lizards and birds (turkey).

Parthenocarpy is the formation of fruits without fertilization.
Autogamy refers to self-pollination.
Syngamy refers to the physical union of a male and female gamete.

Hence, the correct answer is option 4) Parthenogenesis.

Question 2: In some species, parthenogenesis may alternate with sexual reproduction This process is called

Complete parthenogenesis
Incomplete or cyclic parthenogenesis
Both the above
None of the above

Answer: In incomplete or cyclic parthenogenesis, organisms alternate between sexual reproduction and parthenogenesis depending on environmental conditions or season. This is commonly observed in aphids, rotifers, and some insects. Complete parthenogenesis occurs when the entire life cycle proceeds without fertilization (e.g., some wasps).

Hence, the correct answer is option 2) Incomplete or cyclic parthenogenesis

Question 3: The parthenogenic organisms are following

Rotifers
Honey bee
Lizard and turkey bird
All of these

Answer: Parthenogenesis—In a few organisms, the female gamete undergoes development to form new organisms without fertilisation.

E.g., rotifers, honeybees, and even some lizards and birds (turkey).

Hence, the correct answer is option 4) All of these

Also Read:

Micropropagation	Sporulation
Syngamy	Morphallaxis
Difference Between Partenocarpy and Parthenogenesis	Difference Between Apomixis and Parthenogenesis

Recommended video on Parthenogenesis

Frequently Asked Questions (FAQs)

1. What is parthenogenesis?

Parthenogenesis is the type of asexual reproduction where the egg develops into a new individual without fertilization. The result is offspring with the same genes as their mother.

2. What is parthenogenesis?

Parthenogenesis is a form of asexual reproduction where an unfertilized egg develops into a new individual without the need for sperm. This process occurs naturally in some plants, insects, and reptiles, allowing females to produce offspring without mating.

3. What are the types of parthenogenesis?

There are mainly three types of parthenogenesis: obligate parthenogenesis, facultative parthenogenesis, and cyclic parthenogenesis.

4. In which organisms is parthenogenesis commonly observed?

Typical cases of parthenogenesis are usually seen in specific insects, such as aphids; in reptiles, for example, certain lizards; and among plants, for example, dandelions.

5. What are the advantages of parthenogenesis?

Advantages of parthenogenesis include rapid population growth, genetic uniformity, and independence from a mate.

6. What are the disadvantages of parthenogenesis?

Disadvantages of parthenogenesis are absence of genetic diversity, limited adaptability to changes in the environment, and possible inbreeding.

7. How does parthenogenesis affect genetic diversity?

Parthenogenesis generally reduces genetic diversity within a population because offspring inherit genetic material from only one parent. This can make species less adaptable to environmental changes and more susceptible to diseases.

8. What is the Hayflick limit, and how does it relate to parthenogenesis?

The Hayflick limit is the number of times a cell can divide before entering senescence. In parthenogenetic species, this limit may pose a challenge for long-term survival, as the lack of genetic recombination can lead to the accumulation of harmful mutations over generations.

9. How do parthenogenetic species avoid the accumulation of deleterious mutations?

Some strategies used by parthenogenetic species to avoid harmful mutations include:

10. What is the evolutionary significance of parthenogenesis?

Parthenogenesis allows species to reproduce quickly and colonize new environments, especially when males are scarce. It can be advantageous in stable environments but may reduce genetic diversity and adaptability to changing conditions over time.

11. How does parthenogenesis affect the sex ratio of a population?

Parthenogenesis can significantly skew the sex ratio of a population. In many cases, it leads to female-biased populations, as most parthenogenetic offspring are female. However, in some species like honeybees, parthenogenesis produces only males.

12. Can parthenogenesis occur in mammals?

Natural parthenogenesis has not been observed in mammals. However, scientists have induced parthenogenesis in laboratory settings using mammalian eggs, including those from mice and rabbits. These experiments have not resulted in viable offspring.

13. How does parthenogenesis occur in honeybees?

In honeybees, unfertilized eggs develop into male drones through arrhenotokous parthenogenesis. The queen bee can control whether she lays fertilized eggs (which become female workers or queens) or unfertilized eggs (which become males).

14. What are some examples of animals that reproduce through parthenogenesis?

Some animals that can reproduce through parthenogenesis include:

15. How does temperature affect parthenogenesis in some species?

In some species, particularly reptiles, temperature can influence the occurrence of parthenogenesis. For example, extreme temperatures or environmental stress may trigger parthenogenetic reproduction in species that normally reproduce sexually.

16. What is geographical parthenogenesis?

Geographical parthenogenesis refers to the phenomenon where parthenogenetic populations of a species tend to have broader and more northern distributions compared to their sexual counterparts. This pattern is observed in various plants and animals.

17. How does parthenogenesis differ from sexual reproduction?

In parthenogenesis, offspring develop from unfertilized eggs and inherit genetic material only from the mother. Sexual reproduction, on the other hand, involves the fusion of male and female gametes, resulting in offspring with genetic contributions from both parents.

18. How does parthenogenesis affect the concept of sexual selection?

Parthenogenesis eliminates or greatly reduces the role of sexual selection, as there is no need for mate choice or competition for mates. This can lead to the loss of sexually selected traits and different evolutionary trajectories compared to sexually reproducing species.

19. How does parthenogenesis affect the concept of kin selection?

Parthenogenesis produces offspring that are genetically identical or very similar to the mother, leading to high relatedness within populations. This can influence the evolution of social behaviors and cooperation through kin selection, potentially promoting altruistic behaviors among individuals.

20. How does parthenogenesis affect the concept of sexual conflict?

Parthenogenesis eliminates sexual conflict, which arises from the different evolutionary interests of males and females in sexual species. This absence of conflict can lead to the evolution of different traits and behaviors in parthenogenetic species compared to their sexual counterparts.

21. How does parthenogenesis affect the concept of genetic drift?

Parthenogenesis can amplify the effects of genetic drift, as the effective population size is often smaller in parthenogenetic populations. This can lead to rapid fixation of alleles and loss of genetic diversity, potentially increasing the risk of extinction for parthenogenetic lineages.

22. How do parthenogenetic species maintain genetic variation?

Some parthenogenetic species maintain genetic variation through mechanisms such as:

23. What is the role of meiosis in parthenogenesis?

In automictic parthenogenesis, meiosis still occurs, but the egg is restored to a diploid state through various mechanisms, such as fusion of meiotic products or duplication of chromosomes. In apomictic parthenogenesis, meiosis is bypassed entirely, and eggs are produced through mitosis.

24. How does parthenogenesis in plants differ from that in animals?

Parthenogenesis in plants, also called apomixis, often involves the production of seeds without fertilization. In animals, parthenogenesis typically results in the direct development of offspring from unfertilized eggs. Plant parthenogenesis is more common and diverse in its mechanisms.

25. How do parthenogenetic species maintain telomere length across generations?

Some parthenogenetic species have evolved mechanisms to maintain telomere length, such as:

26. What is the relationship between polyploidy and parthenogenesis?

Polyploidy, the presence of multiple sets of chromosomes, is often associated with parthenogenesis. Many parthenogenetic species are polyploid, which can provide genetic redundancy and help mask deleterious mutations, potentially contributing to the long-term success of parthenogenetic lineages.

27. What are the potential applications of parthenogenesis in agriculture?

Parthenogenesis in agriculture could be used to:

28. What is the "two-fold cost of sex," and how does parthenogenesis avoid it?

The "two-fold cost of sex" refers to the idea that sexual reproduction is inefficient because only females produce offspring, while males consume resources without directly contributing to reproduction. Parthenogenesis avoids this cost by allowing all individuals in a population to produce offspring.

29. How does parthenogenesis affect the concept of male parental investment?

Parthenogenesis eliminates the need for male parental investment, as females can produce offspring without mating. This can lead to the evolution of different reproductive strategies and social structures in parthenogenetic species compared to their sexually reproducing relatives.

30. How does parthenogenesis affect the rate of evolution?

Parthenogenesis can slow down the rate of evolution because it reduces genetic recombination and variation. However, it can also allow beneficial mutations to spread quickly through a population without being diluted by sexual reproduction.

31. How does parthenogenesis affect the concept of species?

Parthenogenesis challenges traditional species concepts based on reproductive isolation, as parthenogenetic lineages can evolve independently without gene flow. This has led to debates about how to classify and define species in parthenogenetic groups.

32. What are the main types of parthenogenesis?

The two main types of parthenogenesis are:

33. What is facultative parthenogenesis?

Facultative parthenogenesis is a type of parthenogenesis where an organism can reproduce both sexually and asexually, depending on environmental conditions. This flexibility allows the species to adapt to changing circumstances and optimize reproduction.

34. What is thelytoky in parthenogenesis?

Thelytoky is a form of parthenogenesis where unfertilized eggs develop into females. This is the most common type of parthenogenesis and is found in many insects, such as aphids and some bees.

35. What is cyclic parthenogenesis?

Cyclic parthenogenesis is a reproductive strategy where organisms alternate between sexual and parthenogenetic reproduction depending on environmental conditions. This is common in some crustaceans, like water fleas (Daphnia), which reproduce parthenogenetically under favorable conditions and switch to sexual reproduction when conditions deteriorate.

36. What are the challenges in studying parthenogenesis in natural populations?

Challenges in studying parthenogenesis in natural populations include:

37. What is the difference between parthenogenesis and hermaphroditism?

Parthenogenesis involves the development of unfertilized eggs into new individuals, while hermaphroditism is the presence of both male and female reproductive organs in a single organism. Hermaphrodites can self-fertilize or mate with other individuals, unlike parthenogenetic organisms.

38. What is the relationship between parthenogenesis and asexual reproduction in unicellular organisms?

While both are forms of asexual reproduction, parthenogenesis specifically refers to the development of unfertilized eggs in multicellular organisms. Asexual reproduction in unicellular organisms, such as binary fission, does not involve egg cells and is generally simpler in terms of developmental processes.

39. How does parthenogenesis affect the concept of sexual dimorphism?

Parthenogenetic species often show reduced sexual dimorphism compared to their sexual relatives, as there is no need for sex-specific traits related to mating or reproduction. This can lead to the loss or reduction of secondary sexual characteristics over time.

40. How does parthenogenesis affect the concept of reproductive assurance?

Parthenogenesis provides strong reproductive assurance, as females can produce offspring without the need for mates. This can be particularly advantageous in low-density populations or when colonizing new habitats, ensuring the continuation of the species even when sexual reproduction is not possible.

41. What is the role of endosymbionts in parthenogenesis?

Endosymbionts, such as the bacteria Wolbachia, can induce parthenogenesis in some arthropod species. These microorganisms manipulate the host's reproductive system, often by feminizing genetic males or causing cytoplasmic incompatibility, which can lead to parthenogenetic reproduction.

42. How does parthenogenesis affect the concept of genetic load?

Genetic load, the reduction in population fitness due to deleterious mutations, can accumulate more rapidly in parthenogenetic populations due to the lack of genetic recombination. However, some parthenogenetic species have evolved mechanisms to mitigate this effect, such as efficient DNA repair or polyploidy.

43. What is the relationship between parthenogenesis and invasive species?

Parthenogenesis can contribute to the success of invasive species by allowing rapid population growth from a single individual. This reproductive strategy enables colonization of new habitats even when population densities are low, potentially giving parthenogenetic species an advantage in invading new territories.

44. What is the "frozen niche variation" hypothesis in relation to parthenogenesis?

The "frozen niche variation" hypothesis suggests that parthenogenetic lineages can freeze and maintain specific genetic combinations adapted to particular ecological niches. This allows them to exploit a wider range of environments compared to their sexual counterparts, potentially explaining the success of some parthenogenetic species.

45. How does parthenogenesis affect the concept of Muller's ratchet?

Muller's ratchet is the process by which asexual populations accumulate deleterious mutations over time. Parthenogenetic species are particularly susceptible to this effect due to the lack of genetic recombination. However, some parthenogenetic lineages have evolved mechanisms to counteract Muller's ratchet, such as efficient DNA repair or occasional sexual reproduction.

46. What is the role of epigenetics in parthenogenesis?

Epigenetic mechanisms, such as DNA methylation and histone modifications, play a crucial role in regulating gene expression during parthenogenetic development. These mechanisms can compensate for the absence of paternal genetic contributions and ensure proper embryonic development in parthenogenetic species.

47. What are the potential applications of parthenogenesis in conservation biology?

Parthenogenesis could be used in conservation efforts to:

48. What is the relationship between parthenogenesis and hybridization?

Hybridization can sometimes lead to the emergence of parthenogenetic lineages, particularly in plants. These hybrid parthenogenetic species can combine traits from both parent species and may be able to exploit new ecological niches. Additionally, some parthenogenetic species may occasionally hybridize with related sexual species, introducing new genetic variation.

49. What is the role of genomic imprinting in parthenogenesis?

Genomic imprinting, where certain genes are expressed differently depending on their parental origin, can pose challenges for parthenogenetic development. Some parthenogenetic species have evolved mechanisms to overcome these imprinting effects, such as modified gene expression patterns or loss of imprinting for specific genes.

50. How does parthenogenesis affect the concept of meiotic drive?

Meiotic drive, the biased transmission of certain alleles during meiosis, can have different consequences in parthenogenetic species compared to sexual ones. In some cases, parthenogenesis may allow the rapid spread of driving alleles, while in others, it may limit their effects due to the absence of genetic recombination.

51. What are the energetic costs and benefits of parthenogenesis compared to sexual reproduction?

Parthenogenesis can be energetically advantageous because:

52. How does parthenogenesis affect the concept of bet-hedging in reproduction?

Parthenogenesis can be seen as a form of reproductive bet-hedging, where organisms produce genetically similar offspring adapted to current conditions. This strategy can be advantageous in stable environments but may be less effective in variable or unpredictable conditions compared to the genetic diversity produced by sexual reproduction.

53. What is the role of transposable elements in the evolution of parthenogenesis?

Transposable elements, or "jumping genes," can play a role in the evolution of parthenogenesis by:

54. How does parthenogenesis affect the concept of genetic hitchhiking?

Genetic hitchhiking, where neutral alleles increase in frequency due to their proximity to beneficial alleles, can be more pronounced in parthenogenetic species. The lack of recombination in many parthenogenetic lineages means that entire chromosomes or large genomic regions can be swept to fixation together, potentially leading to rapid genome-wide changes.

55. What are the challenges and opportunities in engineering parthenogenesis in typically sexual species?

Engineering parthenogenesis in sexual species presents several challenges and opportunities: