Polyploidization is the process by which a cell or organism acquires more than two complete sets of chromosomes, leading to a state of polyploidy. This can arise from various mechanisms, including errors in cell division (specifically, errors in meiosis or mitosis), hybridization between species, or experimental manipulation. Polyploidization is a significant evolutionary force in plants and also occurs in some animals and fungi, impacting genome size, gene dosage, and phenotypic traits. The consequences of Polyploidization can range from increased cell size and altered metabolism to novel morphological characteristics and reproductive isolation. The creation of a genome with multiple copies of all genes has many effects, making Polyploidization a source of genetic diversity and potentially an impetus for adaptation and speciation. This process is considered a major driver of the evolutionary diversification of species
Polyploidization meaning with examples
- In plants, whole-genome duplication (polyploidization) is common and can result in larger flowers and fruit. For instance, the cultivated strawberry (Fragaria × ananassa) is an octoploid, contributing to its large size and desirable fruit characteristics. The increased genetic diversity arising from Polyploidization allows the plant to adapt quicker in changing environments, enhancing chances of survival in unfavorable environments, as has been documented in plant species across the world.
- Experimental induction of Polyploidization has been used to improve crop yield and stress tolerance in some economically important plants. Scientists use chemicals like colchicine, which prevents the formation of the spindle during cell division to achieve this. The resulting polyploids often show increased size and vigor, which are desirable traits. This is a common method used to change the characteristics of agricultural and garden-based plants, such as the creation of seedless watermelons.
- Hybridization between closely related species can sometimes lead to allopolyploidization, where the offspring inherit chromosome sets from both parents. This can result in the formation of new species that are reproductively isolated from their parent species. An example is the Brassica species. These newly formed plants can fill previously vacant ecological niches due to the genetic novelty, or may lead to changes of an old niche in their environment, increasing the complexity of the landscape.
- In some animals, particularly in fish, Polyploidization has played a role in their evolutionary history. For example, some species of salmon have experienced genome duplication events, which may have contributed to their adaptive radiation. Research shows that increased genetic information from a duplication event, allows the animal to adapt to harsh environments. This extra DNA can be used for adaptation and environmental resilience, making Polyploidization a source of diversity.