Polyploid complex
Encyclopedia
A polyploid complex is a group of interrelated and interbreeding plants that also have differing levels of ploidy
that can allow genetic exchanges between unrelated species.
The polyploid complex was first described by E. B. Babcock
and G. Ledyard Stebbins
in their 1938 monograph The American Species of Crepis: their interrelationships and distribution as affected by polyploidy and apomixis. In Crepis
and some other herbaceous perennial species, a polyploid complex may arise where there are at least 2 genetically isolated diploid populations, in addition to auto- and allopolyploid derivatives that coexist and interbreed (hybridise). Thus a complex network of interrelated forms may exist where the polyploid forms allow for genetic exchange between the diploid species that are otherwise unable to breed.
A polyploid complex has also been well described in Glycine
.
This complex situation does not fit well within the biological species concept of Ernst Mayr
which defines a species as "groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups".
Ploidy
Ploidy is the number of sets of chromosomes in a biological cell.Human sex cells have one complete set of chromosomes from the male or female parent. Sex cells, also called gametes, combine to produce somatic cells. Somatic cells, therefore, have twice as many chromosomes. The haploid number is...
that can allow genetic exchanges between unrelated species.
The polyploid complex was first described by E. B. Babcock
E. B. Babcock
Ernest Brown Babcock was an United States plant geneticist. His pioneering work on the genetics of the genus Crepis and his more than 100 published articles explaining plant evolution primarily in terms of genetics mark him as a pioneer in the application of genetics research.- References :*...
and G. Ledyard Stebbins
G. Ledyard Stebbins
George Ledyard Stebbins, Jr. was an American botanist and geneticist who is widely regarded as one of the leading evolutionary biologists of the 20th century. Stebbins received his Ph.D. in botany from Harvard University in 1931. He went on to the University of California, Berkeley, where his work...
in their 1938 monograph The American Species of Crepis: their interrelationships and distribution as affected by polyploidy and apomixis. In Crepis
Crepis
Crepis, commonly known in some parts of the world as hawksbeard or hawk's-beard , is a genus of about 200 annual and perennial flowering plants of the family Asteraceae superficially resembling the dandelion, the most conspicuous difference being that Crepis usually has branching...
and some other herbaceous perennial species, a polyploid complex may arise where there are at least 2 genetically isolated diploid populations, in addition to auto- and allopolyploid derivatives that coexist and interbreed (hybridise). Thus a complex network of interrelated forms may exist where the polyploid forms allow for genetic exchange between the diploid species that are otherwise unable to breed.
A polyploid complex has also been well described in Glycine
Glycine (plant)
Glycine is a genus in the bean family Fabaceae. The best known species is the soybean . While the majority of the species are found only in Australia, the soybean's native range is in East Asia. A few species extend from Australia to East Asia Glycine is a genus in the bean family Fabaceae. The...
.
This complex situation does not fit well within the biological species concept of Ernst Mayr
Ernst Mayr
Ernst Walter Mayr was one of the 20th century's leading evolutionary biologists. He was also a renowned taxonomist, tropical explorer, ornithologist, historian of science, and naturalist...
which defines a species as "groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups".