Polyploidy occurs in some animals, such as goldfish[1] , salmon, and salamanders, but is especially common among ferns and flowering plants (see Hibiscus rosa-sinensis), including both wild and cultivated species. Wheat, for example, after millennia of hybridization and modification by humans, has strains that are diploid (two sets of chromosomes), tetraploid (four sets of chromosomes) with the common name of durum or macaroni wheat, and hexaploid (six sets of chromosomes) with the common name of bread wheat. Many agriculturally important plants of the genus Brassica are also tetraploids; their relationship is described by the Triangle of U.
Polyploidy also occurs normally in some animal tissues, such as human muscle tissues.[2]
The occurrence of polyploidy is a mechanism of speciation and is known to have resulted in new species of the plant Salsify (also known as "goatsbeard").
Speciation via polyploidy: A diploid cell undergoes failed meiosis, producing diploid gametes, which self-fertilize to produce a tetraploid zygote.Polyploidy can be induced in cell culture by some chemicals: the best known is colchicine, which can result in chromosome doubling, though its use may have other less obvious consequences as well. Oryzalin also will double the existing chromosome content.
Contents [hide]
1 Polyploidy types
2 Polyploidy in non-human animals
3 Polyploidy in humans (Aneuploidy)
4 Polyploidy in plants
4.1 Polyploid crops
4.2 Examples of polyploid crops
5 Terminology
5.1 Autopolyploidy
5.2 Allopolyploidy
5.3 Homoeologous
5.3.1 Example of homoeologous chromosomes
5.4 Homologous
5.5 Karyotype
5.6 Paralogous
5.7 Paleopolyploidy
6 See also
7 References
8 Further reading
9 External links
