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Speciation via polyploidy: A diploid cell undergoes failed meiosis, producing diploid gametes, which self-fertilize to produce a tetraploid zygote. Polyploidy is frequent in plants, some estimates suggesting that 30–80% of living plant species are polyploid, and many lineages show evidence of ancient polyploidy (paleopolyploidy) in their genomes.
Differences between plant and animal physiology and reproduction cause minor differences in how they evolve. One major difference is the totipotent nature of plant cells, allowing them to reproduce asexually much more easily than most animals. They are also capable of polyploidy – where more than two chromosome sets are inherited from the ...
A diagram that summarizes all well-known paleopolyploidization events. Ancient genome duplications are widespread throughout eukaryotic lineages, particularly in plants. . Studies suggest that the common ancestor of Poaceae, the grass family which includes important crop species such as maize, rice, wheat, and sugar cane, shared a whole genome duplication about
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.
Sympatric speciation events are quite common in plants, which are prone to acquiring multiple homologous sets of chromosomes, resulting in polyploidy. The polyploid offspring occupy the same environment as the parent plants (hence sympatry), but are reproductively isolated.
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]
Speciation via polyploidy: A diploid cell undergoes failed meiosis, producing diploid gametes, which self-fertilize to produce a tetraploid zygote. In plants, this can effectively be a new species, reproductively isolated from its parents, and able to reproduce.
A study comparing the karyotypes of endangered or invasive plants with those of their relatives found that being polyploid as opposed to diploid is associated with a 14% lower risk of being endangered, and a 20% greater chance of being invasive. [61] Polyploidy may be associated with increased vigor and adaptability. [62]