Parallel polyploid speciation: distinct sympatric gene-pools of recurrently derived allo-octoploid Asplenium ferns.
Although polyploidy is widespread, its significance to the generation of biodiversity remains unclear. Many polyploids have been derived recurrently. For a particular polyploid, gene-flow between the products of independent origin is typical where they come into contact. Here, we use AFLP DNA-fingerprinting and chloroplast DNA sequences to demonstrate parallel polyploid speciation within both of the ferns Asplenium cimmeriorum and A. gracillimum. Both of these taxa comprise at least two allopolyploids, recurrently derived from the same progenitor pair. Each of these allopolyploids remain genetically distinguishable even with extensive sympatry, and could therefore be considered distinct species. To our knowledge, parallel speciation on this scale amongst recurrent polyploids has not been previously reported. With their parallel origins, these 'evolutionary replicates' provide an unrivalled opportunity to investigate how the reproductive barriers and ecological differentiation necessary for speciation arise following polyploidy.
Perrie
Leon R
LR
Museum of New Zealand Te Papa Tongarewa, PO Box 467, Wellington, New Zealand. leonp@tepapa.govt.nz
Shepherd
Lara D
LD
De Lange
Peter J
PJ
Brownsey
Patrick J
PJ
D054458:Amplified Fragment Length Polymorphism Analysis; D016172:DNA Fingerprinting; D018742:DNA, Chloroplast / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D029624:Ferns / Q000145:classification / Q000235:genetics*; D051456:Gene Flow; D005788:Gene Pool; D049810:Genetic Speciation; D006239:Haplotypes; D011123:Polyploidy; D017422:Sequence Analysis, DNA
D018742:DNA, Chloroplast; D018744:DNA, Plant