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Polyploidization is widespread in plants and animals, and is an important mechanism of speciation. Genome sequencing and related molecular systematics and bioinformatics studies on plants and animals in recent years support the view that species have been shaped by whole genome duplication during evolution. It is predicted that polyploidy should be more common in temperate than in tropical breeders because environmental fluctuations may promote unreduced gamete formation, it should be most common in organisms with sufficient numbers of gametes that random meiotic problems can be overcome, and it should be more frequent when mechanisms to promote assortative mating are a direct byproduct of genome duplication. What does polyploidization mean? (genetics) Hybridization that leads to polyploidy. (noun) An understanding of the mechanisms whereby genetic defects and teratogenic exposures become manifest as developmental anomalies of varying severity requires experimental models that accurately reproduce the spectrum of defects seen in human HPE. Mechanisms whereby nerve growth factor increases diacylglycerol levels in differentiating PC12 cells Jianxue Li, Richard J. Wurtman) Department of Brain and Cogniti˝e Sciences, E25-604, Massachusetts Institute of Technology, Cambridge, MA 02139, USA Accepted 17 November 1998 Abstract alternative mechanisms may be expressed under different environmental and host conditions or even at different host surfaces.

(noun) 2015-04-27 · What does polyploidization mean? A spoken definition of polyploidization. Intro Sound: Typewriter - Tamskp Licensed under CC:BA 3.0 Outro Music: Groove Groov Common bread wheat (Triticum aestivum) is an example of a common amphiploid. This hexaploid came into being about 7,000 years ago from hybridization between rivet wheat ( T. turgidum ), a tetraploid, and Tausch's goatgrass ( Aegilops tauschii ), a diploid. 5 In fact, Talbert et al. (1998) say it arose repeatedly as the result of multiple hybridization events. Definition of polyploid in the Definitions.net dictionary.

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Triploids, however, confront problems of chromosomal pairing and segregation during meiosis, which may cause aneuploid gametes and result in sterility; therefore, triploids are believed to primarily In mice and humans, polyploidization is believed to also occur primarily by failed cytokinesis. However, the kinetics of polyploidization differs somewhat between mice and rats.

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Polyploidization is a common mechanism whereby

Genome sequencing and The most common mechanism of polyploidization acting in plant tissues and cells appears to be supernumerary chromosome reproduction.

Finally, apomixis is a particularly favorable mechanism to ensure reproduction after polyploidization. Fate of duplicated genes in polyploids Force et al. (1999): Gene duplication can be arisen from tandem gene duplication or from polyploidization. There are several views regarding the fate of duplicated genes.
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Endomitosis, for in-stance, is most often used in reference to the The model proposed suggests that polyploidy should be most common in: (i) populations exposed to environmental fluctuations during their breeding season that may induce higher frequencies of unreduced gametes; (ii) organisms producing sufficient numbers of gametes that random meiotic problems can be filtered; and (iii) in organisms for which mechanisms to promote assortative mating have the capacity to change as a direct consequence of polyploidization. Polyploidization is widespread in plants and animals, and is an important mechanism of speciation. Genome sequencing and related molecular systematics and bioinformatics studies on plants and animals in recent years support the view that species have been shaped by whole genome duplication during evolution.

This hexaploid came into being about 7,000 years ago from hybridization between rivet wheat ( T. turgidum ), a tetraploid, and Tausch's goatgrass ( Aegilops tauschii ), a diploid. 5 In fact, Talbert et al. (1998) say it arose repeatedly as the result of multiple hybridization events.
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In addition, an uncommon mechanism of polyploid formation involves poly spermy where one egg is fertilized by several male nucleuse s as commonl y obse rved in orchids (Ramsey and Schemske, 1998). Polyploidy is when the number of chromosomesin a cell becomesdoubled. This can happen by a mutation that simply makes two copies. It can also happen when the chromosomes from two different species aremixed.