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In some situations, polyploid crops are preferred because they are sterile. For example, many seedless fruit varieties are seedless as a result of polyploidy. Such crops are propagated using asexual techniques, such as grafting. Polyploidy in crop plants is most commonly induced by treating seeds with the chemical colchicine.
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.
It is possible on rare occasions for ploidy to increase in the germline, which can result in polyploid offspring and ultimately polyploid species. This is an important evolutionary mechanism in both plants and animals and is known as a primary driver of speciation . [ 8 ]
Polyploid (usu. pentaploid, triploid) 2n=5x(3x)=150(90) Robert et al., 2008; Hughes et al., 2007: Variable ploidy, polyploid event not recent Agave sisalana: Sisal: Asparagaceae: Allopolyploid origin: Confirmed: Uncertain: Polyploid (usu. pentaploid, hexaploid) 2n=5x(6x)=150(180) Robert et al., 2008: Variable ploidy, polyploid event not recent ...
It has been suggested that many polyploidization events created new species, via a gain of adaptive traits, or by sexual incompatibility with their diploid counterparts. An example would be the recent speciation of allopolyploid Spartina — S. anglica; the polyploid plant is so successful that it is listed as an invasive species in many ...
In these polyploid unisexual females, an extra premeiotic endomitotic replication of the genome, doubles the number of chromosomes. [46] As a result, the mature eggs that are produced subsequent to the two meiotic divisions have the same ploidy as the somatic cells of the adult female salamander.
Examples include the very tiny handle on maple syrup bottles, faux buckles on shoes, the floppy disk 'save' icon, or the sound of a shutter on a cell phone camera. Image credits: Festina_lente123 #12
The Hardy–Weinberg principle may also be generalized to polyploid systems, that is, for organisms that have more than two copies of each chromosome. Consider again only two alleles. The diploid case is the binomial expansion of: (+) and therefore the polyploid case is the binomial expansion of: