| Publication Type: | Journal Article |
| Year of Publication: | 2000 |
| Authors: | D. J. Harris |
| Journal: | Edinburgh Journal ofBotany |
| Volume: | 57 |
| Pagination: | 377-395 |
| Keywords: | Aframomum African forest herbs gingers molecular evolution speciation species diversity Zingiberaceae |
| Abstract: | Internal transcribed spacer (ITS) nrDNA sequences of 42 accessions(representing 28 species) of Aframomum revealed an unusually lowlevel of sequence variation, suggesting a recent radiation of the genus inAfrica. The sample of species analysed includes all the main morphologicalvariation and is based on wide geographical sampling. The Aframomumsequences varied from 187bp to 190bp (ITS 1) and 215bp to 216bp (ITS 2). Pair-wisesequence difference between accessions varied from 0% (e.g. A.luteoalbum and A.thonneri) to 2.74% (e.g. A. sp.nov.B to A.pseudostipulare). This contrasts with a comparabledata set for the SE Asian genus Alpinia in the same tribe (Alpineae) in which maximum pair-wise difference is six times greater (range 0.5–15.6%).A parsimony analysis of the in-group and out-group taxa supports the monophylyof the genus Aframomum, but does not resolve the relationships betweenthe in-group species. Four putative multi-species groups, however, have somejackknife support. The species sampled vary greatly in vegetative, floraland fruit characters. This morphological variation is not reflected in theITS sequence data. This may be a result of rapid radiation under conditionsof Pleistocene climatic change and effective dispersal of seeds by primates. |