Eupolyploidy As a Mode in Plant Speciation

When discussing phenomena of whole genome duplication, the terms “neopolyploid,” “mesopolyploid,” and “paleopolyploid” are used in their modern “postgenomic” interpretation. In our opinion, in long chain of gradual changes of polyploid genome during the transition from neopolyploids to paleopolyploids, it makes sense to single out the eupolyploid stage—a state of a polyploid in which its polyploid nature is beyond doubt, but the genome (karyotype) of the eupolyploid, unlike the neopolyploid, is already relatively stable. Most so-called “polypoid species” are actually eupolyplids, the polyploid nature of their karyotype is beyond doubt among researchers—geneticists, karyologists, and florists. Optionally, eupolyploids take part in new rounds of interspecific hybridization either maintaining the level of ploidy of the parents or with the emergence of an allopolyploid of a higher level of ploidy. Eupolyploidization of the genome is a mechanism of radical and rapid plant speciation. In this way, tens of thousands of species of modern plants arose. Successful combinations of alleles of eupolyploid subgenomes, large sizes characteristic of high polyploids, and frequent transition to asexual reproduction can contribute to the successful development of new areas by eupolyploids, adaptation to extreme conditions of existence at the edge of areas, but not to the acquisition of new aromorphoses—this is speciation, but speciation on an already achieved level of evolutionary complexity, a step that does not in itself lead to progressive evolution.