Although homoploid hybrid speciation is increasingly recognized as an important phenomenon in plant evolution, its role in adaptive radiations is poorly documented. We studied a clade of seven extant species of Scaevola that are endemic to the Hawaiian Islands and show substantial ecological and morphological diversity. We estimated the genealogies for alleles isolated from multiple accessions of each species at four nuclear loci: the ITS region, and the introns of three nuclear genes, LEAFY (LFY), NITRATE REDUCTASE (NIA), and GLYCERALDEHYDE 3-PHOSPHATE DEHYDROGENASE (G3PDH). For five of the seven species, there was complete concordance among the genealogies estimated from the four loci and, when all four regions were combined, the relationships among these five species were fully resolved. Inclusion of alleles from the remaining two species, S. procera and S. kilaueae, resulted in incongruence among loci, which appears to reflect a history of hybridization. Based on the distribution of alleles, we infer that S. procera is the result of a homoploid hybrid speciation event between S. gaudichaudii and S. mollis and that S. kilaueae is probably the result of hybrid speciation between S. coriacea and S. chamissoniana. In each case the inferred hybridization is consistent with morphological, ecological, and geographic information. We conclude that homoploid hybrid speciation may be more common than is perceived and may play a role in generating novel combinations of adaptive traits that arise during island radiations.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.