A dated phylogeny and collection records reveal repeated biome shifts in the African genus <it>Coccinia </it>(Cucurbitaceae)
<p>Abstract</p> <p>Background</p> <p>Conservatism in climatic tolerance may limit geographic range expansion and should enhance the effects of habitat fragmentation on population subdivision. Here we study the effects of historical climate change, and the associated hab...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
BMC
2011-01-01
|
| Series: | BMC Evolutionary Biology |
| Online Access: | http://www.biomedcentral.com/1471-2148/11/28 |
| _version_ | 1818978245025988608 |
|---|---|
| author | Renner Susanne S Holstein Norbert |
| author_facet | Renner Susanne S Holstein Norbert |
| author_sort | Renner Susanne S |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Conservatism in climatic tolerance may limit geographic range expansion and should enhance the effects of habitat fragmentation on population subdivision. Here we study the effects of historical climate change, and the associated habitat fragmentation, on diversification in the mostly sub-Saharan cucurbit genus <it>Coccinia</it>, which has 27 species in a broad range of biota from semi-arid habitats to mist forests. Species limits were inferred from morphology, and nuclear and plastid DNA sequence data, using multiple individuals for the widespread species. Climatic tolerances were assessed from the occurrences of 1189 geo-referenced collections and WorldClim variables.</p> <p>Results</p> <p>Nuclear and plastid gene trees included 35 or 65 accessions, representing up to 25 species. The data revealed four species groups, one in southern Africa, one in Central and West African rain forest, one widespread but absent from Central and West African rain forest, and one that occurs from East Africa to southern Africa. A few individuals are differently placed in the plastid and nuclear (<it>LFY</it>) trees or contain two ITS sequence types, indicating hybridization. A molecular clock suggests that the diversification of <it>Coccinia </it>began about 6.9 Ma ago, with most of the extant species diversity dating to the Pliocene. Ancestral biome reconstruction reveals six switches between semi-arid habitats, woodland, and forest, and members of several species pairs differ significantly in their tolerance of different precipitation regimes.</p> <p>Conclusions</p> <p>The most surprising findings of this study are the frequent biome shifts (in a relatively small clade) over just 6 - 7 million years and the limited diversification during and since the Pleistocene. Pleistocene climate oscillations may have been too rapid or too shallow for full reproductive barriers to develop among fragmented populations of <it>Coccinia, </it>which would explain the apparently still ongoing hybridization between certain species. Steeper ecological gradients in East Africa and South Africa appear to have resulted in more advanced allopatric speciation there.</p> |
| first_indexed | 2024-12-20T16:40:34Z |
| format | Article |
| id | doaj.art-3b2acd90f7154756a8bb3448fb3f2b3b |
| institution | Directory Open Access Journal |
| issn | 1471-2148 |
| language | English |
| last_indexed | 2024-12-20T16:40:34Z |
| publishDate | 2011-01-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Evolutionary Biology |
| spelling | doaj.art-3b2acd90f7154756a8bb3448fb3f2b3b2022-12-21T19:33:02ZengBMCBMC Evolutionary Biology1471-21482011-01-011112810.1186/1471-2148-11-28A dated phylogeny and collection records reveal repeated biome shifts in the African genus <it>Coccinia </it>(Cucurbitaceae)Renner Susanne SHolstein Norbert<p>Abstract</p> <p>Background</p> <p>Conservatism in climatic tolerance may limit geographic range expansion and should enhance the effects of habitat fragmentation on population subdivision. Here we study the effects of historical climate change, and the associated habitat fragmentation, on diversification in the mostly sub-Saharan cucurbit genus <it>Coccinia</it>, which has 27 species in a broad range of biota from semi-arid habitats to mist forests. Species limits were inferred from morphology, and nuclear and plastid DNA sequence data, using multiple individuals for the widespread species. Climatic tolerances were assessed from the occurrences of 1189 geo-referenced collections and WorldClim variables.</p> <p>Results</p> <p>Nuclear and plastid gene trees included 35 or 65 accessions, representing up to 25 species. The data revealed four species groups, one in southern Africa, one in Central and West African rain forest, one widespread but absent from Central and West African rain forest, and one that occurs from East Africa to southern Africa. A few individuals are differently placed in the plastid and nuclear (<it>LFY</it>) trees or contain two ITS sequence types, indicating hybridization. A molecular clock suggests that the diversification of <it>Coccinia </it>began about 6.9 Ma ago, with most of the extant species diversity dating to the Pliocene. Ancestral biome reconstruction reveals six switches between semi-arid habitats, woodland, and forest, and members of several species pairs differ significantly in their tolerance of different precipitation regimes.</p> <p>Conclusions</p> <p>The most surprising findings of this study are the frequent biome shifts (in a relatively small clade) over just 6 - 7 million years and the limited diversification during and since the Pleistocene. Pleistocene climate oscillations may have been too rapid or too shallow for full reproductive barriers to develop among fragmented populations of <it>Coccinia, </it>which would explain the apparently still ongoing hybridization between certain species. Steeper ecological gradients in East Africa and South Africa appear to have resulted in more advanced allopatric speciation there.</p>http://www.biomedcentral.com/1471-2148/11/28 |
| spellingShingle | Renner Susanne S Holstein Norbert A dated phylogeny and collection records reveal repeated biome shifts in the African genus <it>Coccinia </it>(Cucurbitaceae) BMC Evolutionary Biology |
| title | A dated phylogeny and collection records reveal repeated biome shifts in the African genus <it>Coccinia </it>(Cucurbitaceae) |
| title_full | A dated phylogeny and collection records reveal repeated biome shifts in the African genus <it>Coccinia </it>(Cucurbitaceae) |
| title_fullStr | A dated phylogeny and collection records reveal repeated biome shifts in the African genus <it>Coccinia </it>(Cucurbitaceae) |
| title_full_unstemmed | A dated phylogeny and collection records reveal repeated biome shifts in the African genus <it>Coccinia </it>(Cucurbitaceae) |
| title_short | A dated phylogeny and collection records reveal repeated biome shifts in the African genus <it>Coccinia </it>(Cucurbitaceae) |
| title_sort | dated phylogeny and collection records reveal repeated biome shifts in the african genus it coccinia it cucurbitaceae |
| url | http://www.biomedcentral.com/1471-2148/11/28 |
| work_keys_str_mv | AT rennersusannes adatedphylogenyandcollectionrecordsrevealrepeatedbiomeshiftsintheafricangenusitcocciniaitcucurbitaceae AT holsteinnorbert adatedphylogenyandcollectionrecordsrevealrepeatedbiomeshiftsintheafricangenusitcocciniaitcucurbitaceae AT rennersusannes datedphylogenyandcollectionrecordsrevealrepeatedbiomeshiftsintheafricangenusitcocciniaitcucurbitaceae AT holsteinnorbert datedphylogenyandcollectionrecordsrevealrepeatedbiomeshiftsintheafricangenusitcocciniaitcucurbitaceae |