Dating the origins of polyploidy events
It is speculated that intergenomic exchanges, like crossing over during meiosis, may play a role.
Intergenomic exchanges are often lethal due to the fact that chromosomes in unisexual species are homeologous.
Courtship behavior between females of the same species has been observed in Ambystoma platineum, and has been posited to induce either oviposition of ovulation, though the precise utility of the behavior is unknown.
As part of the 's Centennial Review series, Douglas Soltis, Clayton Visger, and Pamela Soltis (University of Florida: Dept.As Soltis explains, "If two plants with 12 chromosomes hybridized, you would expect the offspring to have 12 chromosomes, right? That is genome doubling -- every chromosome, every gene duplicated -- wow, 2X the genetic material to work with instantaneously! In the mid-20th century Stebbins synthesized what was known at that time about polyploidy, classifying different types of ploidy, discussing ancient polyploidy events, and investigating hybridizing species and polyploid derivatives." In their review, Soltis and colleagues emphasize that polyploidy and the important role it has played, especially in plant evolution, would not have gained the recognition it deserves would it not have been for its staunch proponent, G. However, Stebbins thought that polyploidy would only be an advantage for species in environments that might change rapidly, and that it would not be particularly advantageous in stable ecosystems, or in competition with widespread diploid species.While this might seem surprising, in fact most plant species are polyploid.Polyploidy, or genome doubling, was first discovered over a century ago, but only recently, with the development of molecular tools, has it been revealed just how ubiquitous it is.
It has been documented in the European water frog complex of the genus Pelophylax, which includes three hybridogenic forms.