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Polyploidy is the result of whole-genome duplication during the evolution of species. It may occur due to abnormal cell division, either during mitosis, or more commonly from the failure of chromosomes to separate during meiosis or from the fertilization of an egg by more than one sperm. [1]
This work continued with the 1947 paper "Types of polyploids: their classification and significance", which detailed a system for the classification of polyploids and described Stebbins' ideas about the role of paleopolyploidy in angiosperm evolution, where he argued that chromosome number may be a useful tool for the construction of ...
Polyploid speciation, which involves changes in chromosome number, is a more common phenomenon, especially in plant species. Polyploidy is a mechanism that has caused many rapid speciation events in sympatry because offspring of, for example, tetraploid x diploid matings often result in triploid sterile progeny. [257]
Polyploidy may be associated with increased vigor and adaptability. [62] Some studies suggest that selection is more likely to favor diploidy in host species and haploidy in parasite species. [ 63 ] However, polyploidization is associated with an increase in transposable element content [ 64 ] [ 65 ] and relaxed purifying selection on recessive ...
Polyploidy is important to wheat classification for three reasons: Wheats within one ploidy level will be more closely related to each other. Ploidy level influences some plant characteristics. For example, higher levels of ploidy tend to be linked to larger cell size. Polyploidy brings new genomes into a species.
Polyploidy, or whole genome duplication is a product of nondisjunction during meiosis which results in additional copies of the entire genome. Polyploidy is common in plants, but it has also occurred in animals, with two rounds of whole genome duplication in the vertebrate lineage leading to humans. [4]
Speciation via polyploidy: A diploid cell undergoes failed meiosis, producing diploid gametes, which self-fertilize to produce a tetraploid zygote.. Polyploidy is pervasive in plants and some estimates suggest that 30–80% of living plant species are polyploid, and many lineages show evidence of ancient polyploidy (paleopolyploidy) in their genomes.
[25] [28] Polyploidy events will result in higher levels of heterozygosity, and, over time, can lead to an increase in the total number of functional genes in the genome. As time passes after a genome duplication event, many genes will change function as a result of either change in duplicate gene function for both allo- and autopolyploid ...