Literaturdatenbank
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Palkovacs, E. P., Gerlach, J., & Caccone, A. (2002). The evolutionary origin of indian ocean tortoises (dipsochelys). Molecular Phylogenetics and Evolution, 24(2), 216–227.
Added by: Admin (14 Aug 2008 20:36:26 UTC) Last edited by: Beate Pfau (06 Dec 2008 17:13:45 UTC) |
| Resource type: Journal Article BibTeX citation key: Palkovacs2002a View all bibliographic details  |
Categories: General Keywords: Aldabrachelys, Aldabrachelys arnoldi, Aldabrachelys dussumieri, Aldabrachelys hololissa, Astrochelys, Astrochelys radiata, Astrochelys yniphora, Genetik = genetics, Geochelone, Pyxis, Pyxis arachnoides, Pyxis planicauda, Schildkröten = turtles + tortoises, Testudinidae Creators: Caccone, Gerlach, Palkovacs Collection: Molecular Phylogenetics and Evolution |
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| Abstract |
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Testudinidae Geochelone Dipsochelys arnoldi dussumieri hololissa Today, the only surviving wild population of giant tortoises in the Indian Ocean occurs on the island of Aldabra. However, giant tortoises once inhabited islands throughout the western Indian Ocean. Madagascar, Africa, and India have all been suggested as possible sources of colonization for these islands. To address the origin of Indian Ocean tortoises (Dipsochelys, formerly Geochelone gigantea), we sequenced the 12S, 16S, and cyt b genes of the mitochondrial DNA. Our phylogenetic analysis shows Dipsochelys to be embedded within the Malagasy lineage, providing evidence that Indian Ocean giant tortoises are derived from a common Malagasy ancestor. This result points to Madagascar as the source of colonization for western Indian Ocean islands by giant tortoises. Tortoises are known to survive long oceanic voyages by floating with ocean currents, and thus, currents flowing northward towards the Aldabra archipelago from the east coast of Madagascar would have provided means for the colonization of western Indian Ocean islands. Additionally, we found an accelerated rate of sequence evolution in the two Malagasy Pyxis species examined. This finding supports previous theories that shorter generation time and smaller body size are related to an increase in mitochondrial DNA substitution rate in vertebrates. Added by: Admin Last edited by: Beate Pfau |