The main difference between apomictic and automictic parthenogenesis is that the egg is genetically identical to the mother in apomictic parthenogenesis, whereas the egg is more homozygous than the mother in automictic parthenogenesis.
Apomictic and automictic parthenogenesis are two parthenogenesis types. Parthenogenesis is a reproductive strategy that develops a female gamete into an individual without fertilization.
Key Areas Covered
1. What is Apomictic Parthenogenesis
– Definition, Features, Importance
2. What is Automictic Parthenogenesis
– Definition, Features, Importance
3. Similarities Between Apomictic and Automictic Parthenogenesis
– Outline of Common Features
4. Difference Between Apomictic and Automictic Parthenogenesis
– Comparison of Key Differences
Key Terms
Apomictic Parthenogenesis, Automixis, Automictic Parthenogenesis
What is Apomictic Parthenogenesis
Apomictic parthenogenesis is one of the two types of parthenogenesis undergoing mitotic oogenesis. Therefore, it does not undergo meiosis during the production of female gametes. However, mature egg cells produced by mitosis directly develop into embryos. Also, the egg cells produced by apomictic parthenogenesis are genetically identical to the mother. It means they are full clones of the mother.
Figure 1: Parthenogenesis
Furthermore, parthenogenesis that undergoes meiosis is more complicated. It is collectively called automictic parthenogenesis. There, egg cells become diploid in many ways. Also, they are genetically different from their mothers. Therefore, they are half-clones of the mother.
What is Automictic Parthenogenesis
Automictic parthenogenesis, also called automixis, is the other parthenogenesis type that undergoes meiosis during oogenesis. The chromosomes in the egg cell double before meiosis begins and at the end of the miosis in automictic parthenogenesis. It is called the endomitotic cycle. Fusion of meiotic products results in diploid egg cells. Here, one of the anaphases does not separate chromosomes in automictic parthenogenesis. Or else the two nuclei produced by the meiosis undergo fusion. Sometimes, one of the polar bodies can fuse with the egg cell after maturation.
Figure 2: Effect of Heterozygosity
Moreover, one can consider automictic parthenogenesis as a type of sexual reproduction since it undergoes recombination. However, many consider it a type of asexual reproduction. Therefore, the resulting embryos are parthenogenetic. Also, the embryo’s genetic composition varies in different automixis methods. In the endomitosis and central fusion in anaphase I, the offspring contains more than half of the mother’s genetic material. Therefore, the embryo is heterozygous. Usually, anaphase I separates homologous chromosomes. When crossing over occurs in the central fusion, heterozygosity is not preserved.
Similarities Between Apomictic and Automictic Parthenogenesis
- Apomictic and automictic parthenogenesis are two parthenogenesis types that develop a female egg into an individual.
- The female gamete is always diploid.
- They are a type of asexual reproduction.
Difference Between Apomictic and Automictic Parthenogenesis
Definition
Apomictic parthenogenesis refers to occurring without meiosis through mitotic oogenesis. In contrast, automictic parthenogenesis is a postmeiotic process in which a haploid cell may duplicate its chromosomes or join another haploid cell.
Meiosis
Apomictic parthenogenesis does not undergo meiosis, while automictic parthenogenesis undergoes miosis.
Mitosis
Apomictic parthenogenesis undergoes mitosis, while automictic parthenogenesis does not undergo mitosis.
Process
Apomictic parthenogenesis undergoes regular cell division mitosis, while automictic parthenogenesis undergoes fusion in the postmeiotic cells.
Egg
The egg is genetically identical to the mother in apomictic parthenogenesis, while the egg is more homozygous than the mother in automictic parthenogenesis.
Genetic Diversity
Genetic diversity is high in apomictic parthenogenesis, while genetic diversity is low in automictic parthenogenesis.
Conclusion
In brief, apomictic and automictic parthenogenesis are two parthenogenesis types. They are a type of asexual reproduction in which female gametes develop into individuals. Apomictic parthenogenesis undergoes mitosis, the regular form of cell division. Therefore, the egg is genetically identical to the mother. Importantly, it has a high genetic diversity. In comparison, automictic parthenogenesis is another parthenogenesis type that undergoes meiosis. It undergoes the fusion of postmeiotic cells. However, the egg is more homozygous than the mother. Hence, genetic diversity is low in automictic parthenogenesis. Also, the main difference between apomictic and automictic parthenogenesis is the development of the egg.
References:
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Parthenogenesis. Parthenogenesis – an overview | ScienceDirect Topics. (n.d.).
Image Courtesy:
- “Cnemidophorus-ThreeSpecies” By Alistair J. Cullum – Own work (Attribution) via Commons Wikimedia
- “Central fusion and terminal fusion automixis” By Staticd – Own Work (CC-BY SA 4.0) via Commons Wikimedia
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