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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.
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.
Classification systems serve the purpose of grouping organisms by characteristics common to each group. Plants are distinguished from animals by various traits: they have cell walls made of cellulose, polyploidy, and they exhibit sedentary growth.
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.
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. [60] Polyploidy may be associated with increased vigor and adaptability. [61]
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.
One key to the classification of strawberry species is that they vary in the number of chromosomes. They all have seven basic types of chromosomes, but exhibit different polyploidy. Some species are diploid, having two sets of the seven chromosomes (14 chromosomes total), but others are tetraploid (four sets, 28 chromosomes total), hexaploid ...
The main goals of diploidization are: (1) To ensure proper gene dosage; and (2) to maintain stable cellular division processes. This process does not need to occur rapidly for all chromosomes in one or few steps. In recent polyploid events, segments of the genome may still remain in a tetraploid status.