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| Titel |
Testing the spatial and temporal framework of speciation in an ancient lake species flock: the leech genus Dina (Hirudinea: Erpobdellidae) in Lake Ohrid |
| VerfasserIn |
S. Trajanovski, C. Albrecht, K. Schreiber, R. Schultheiß, T. Stadler, M. Benke, T. Wilke |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 7, no. 11 ; Nr. 7, no. 11 (2010-11-03), S.3387-3402 |
| Datensatznummer |
250005046
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| Publikation (Nr.) |
 copernicus.org/bg-7-3387-2010.pdf |
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| Zusammenfassung |
Ancient Lake Ohrid on the Balkan Peninsula is considered to be the oldest
ancient lake in Europe with a suggested Plio-/Pleistocene age. Its exact
geological age, however, remains unknown. Therefore, molecular clock data of
Lake Ohrid biota may serve as an independent constraint of available
geological data, and may thus help to refine age estimates. Such
evolutionary data may also help unravel potential biotic and abiotic factors
that promote speciation events.
Here, mitochondrial sequencing data of one of the largest groups of endemic
taxa in the Ohrid watershed, the leech genus Dina, is used to test whether it
represents an ancient lake species flock, to study the role of potential
horizontal and vertical barriers in the watershed for evolutionary events,
to estimate the onset of diversification in this group based on molecular
clock analyses, and to compare this data with data from other endemic
species for providing an approximate time frame for the origin of Lake
Ohrid.
Based on the criteria speciosity, monophyly and endemicity, it can be
concluded that Dina spp. from the Ohrid watershed, indeed, represents an ancient
lake species flock. Lineage sorting of its species, however, does not seem
to be complete and/or hybridization may occur. Analyses of population
structures of Dina spp. in the Ohrid watershed indicate a horizontal zonation of
haplotypes from spring and lake populations, corroborating the role of
lake-side springs, particularly the southern feeder springs, for
evolutionary processes in endemic Ohrid taxa. Vertical differentiation of
lake taxa, however, appears to be limited, though differences between
populations from the littoral and the profundal are apparent. Molecular
clock analyses indicate that the most recent common ancestor of extant
species of this flock is approximately 1.99 ± 0.83 million years (Ma)
old, whereas the split of the Ohrid Dina flock from a potential sister taxon
outside the lake is estimated at 8.30 ± 3.60 Ma. Comparisons with other
groups of endemic Ohrid species indicated that in all cases, diversification
within the watershed started ≤2 Ma ago. Thus, this estimate may
provide information on a minimum age for the origin of Lake Ohrid. Maximum
ages are less consistent and generally less reliable. But cautiously, a
maximum age of 3 Ma is suggested. Interestingly, this time frame of
approximately 2–3 Ma ago for the origin of Lake Ohrid, generated
based on genetic data, well fits the time frame most often used in the
literature by geologists. |
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