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Polyploid plants can arise spontaneously in nature by several mechanisms, including meiotic or mitotic failures, and fusion of unreduced (2n) gametes. [41] Both autopolyploids (e.g. potato [ 75 ] ) and allopolyploids (such as canola, wheat and cotton) can be found among both wild and domesticated plant species.
The generic term polyploid is often used to describe cells with three or more sets of chromosomes. [ 4 ] [ 5 ] Virtually all sexually reproducing organisms are made up of somatic cells that are diploid or greater, but ploidy level may vary widely between different organisms, between different tissues within the same organism, and at different ...
The list of organisms by chromosome count describes ploidy or numbers of chromosomes in the cells of various plants, animals, protists, and other living organisms.This number, along with the visual appearance of the chromosome, is known as the karyotype, [1] [2] [3] and can be found by looking at the chromosomes through a microscope.
Thus, paleopolyploidy is identified as a "peak" on the duplicate number vs. Ks graph (shown on the right). However, using Ks plots to identify and document ancient polyploid events can be problematic, as the method fails to identify genome duplications that were followed by massive gene elimination and genome refinement.
Once a polyploid is made, either synthetically or naturally, the genome goes through a period of "genome shock". Genome shock can be defined as a stage in which the genome experiences massive reorganization and structural changes to deal with the external stress (X-ray damage, chromosome duplication, etc.) imposed upon the genome. [ 7 ]
Polyploid speciation is commonly observed in plants because their nature allows them to support genome duplications. Polyploids are considered a new species because the occurrence of a whole genome duplication imposes post-zygotic barriers, which enable reproductive isolation between parent populations and hybrid offspring.
In plants, hybridization mostly generates speciation events, [5] and commonly produces polyploid species. Factors like polyploidy events also plays significant factors for understanding the hybridization events (Example: an F1 hybrid of Jatropha curcas x Ricinus communis ), [ 6 ] because these polyploids tend to have an advantage for the early ...
Polyploid series in related species which consist entirely of multiples of a single basic number are known as euploid. Haplo-diploidy, where one sex is diploid, and the other haploid. It is a common arrangement in the Hymenoptera, and in some other groups.