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Polyploidy is a condition in which the cells of an organism have more than two paired sets of chromosomes. Most species whose cells have nuclei ( eukaryotes ) are diploid , meaning they have two complete sets of chromosomes, one from each of two parents; each set contains the same number of chromosomes, and the chromosomes are joined in pairs ...
Hybridization without change in chromosome number is called homoploid hybrid speciation. [1] This is the situation found in most animal hybrids. For a hybrid to be viable, the chromosomes of the two organisms will have to be very similar, i.e., the parent species must be closely related, or else the difference in chromosome arrangement will ...
Hybridization is an important means of speciation in plants, since polyploidy (having more than two copies of each chromosome) is tolerated in plants more readily than in animals. [ 80 ] [ 81 ] Polyploidy is important in hybrids as it allows reproduction, with the two different sets of chromosomes each being able to pair with an identical ...
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.
Potential evolutionary outcomes of hybridization. While most hybridization events are evolutionary dead ends, hybridization may also lead to speciation reversal where two taxa merge into one or form a hybrid zone between parapatric taxa. Alternatively, only one species may disappear through genetic swamping if introgression is highly asymmetrical.
Fluorescence in situ hybridization (FISH) is a laboratory method used to detect and locate a DNA sequence, often on a particular chromosome. [4]In the 1960s, researchers Joseph Gall and Mary Lou Pardue found that molecular hybridization could be used to identify the position of DNA sequences in situ (i.e., in their natural positions within a chromosome).
For example, homoploid hybridization is hybridization where the offspring have the same ploidy level as the two parental species. This contrasts with a common situation in plants where chromosome doubling accompanies or occurs soon after hybridization. Similarly, homoploid speciation contrasts with polyploid speciation. [citation needed]
Hybridization sometimes results in introgression, which can occur in response to habitat disturbance that puts plant species into contact with each other. [2] Introgression is gene transfer among taxa and is a result of hybridization, followed by repeated backcrossing with parental individuals.