Evidence for male dispersal along the coasts but no migration in pelagic waters in dusky dolphins (Lagenorhynchus obscurus)
Cassens, I.; Van Waerebeek, K.; Best, P.B.; Tzika, A.; Van Helden, A.L.; Crespo, E.A.; Milinkovitch, M.C. (2005). Evidence for male dispersal along the coasts but no migration in pelagic waters in dusky dolphins (Lagenorhynchus obscurus). Mol. Ecol. 14(1): 107-121. http://dx.doi.org/10.1111/j.1365-294X.2004.02407.x
In: Molecular Ecology. Blackwell: Oxford. ISSN 0962-1083; e-ISSN 1365-294X, more
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| Keywords |
Acids > Organic compounds > Organic acids > Nucleic acids > DNA
Aquatic organisms > Marine organisms > Aquatic mammals > Marine mammals
Behaviour > Migrations
Biogeny > Phylogeny
Bioselection > Genetic drift
Environments > Aquatic environment > Pelagic environment
Population characteristics > Population structure > Sex ratio
Cetacea [WoRMS]; Lagenorhynchus obscurus (Gray, 1828) [WoRMS]
ISE, Peru [Marine Regions]; PSE, New Zealand [Marine Regions]; PSW, Argentina [Marine Regions]; PSW, South Africa [Marine Regions]
Marine/Coastal |
| Author keywords |
Cetacea; mtDNA; microsatellites; phylogeography; male-biased gene flow;bottleneck; ancient polymorphism |
| Authors | | Top |
- Cassens, I.
- Van Waerebeek, K., more
- Best, P.B.
- Tzika, A.
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- Van Helden, A.L.
- Crespo, E.A.
- Milinkovitch, M.C., more
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| Abstract |
Using nine nuclear species-specific microsatellite loci and two mitochondrial gene fragments cytochrome b and control region), we investigated the processes that have shaped the geographical distribution of genetic diversity exhibited by contemporary dusky dolphin (Lagenorhynchus obscurus) populations. A total of 221 individuals from four locations (Peru, Argentina, southern Africa, and New Zealand) were assayed, covering most of the species’ distribution range. Although our analyses identify a general demographic decline in the Peruvian dusky dolphin stock (recently affected by high natural and humaninduced mortality levels), comparison between the different molecular markers hint at an ancient bottleneck that predates recent El Niño oscillations and human exploitation. Moreover, we find evidence of a difference in dispersal behaviour of dusky dolphins along the South American coast and across the Atlantic. While data in Peruvian and Argentine waters are best explained by male-specific gene flow between these two populations, our analyses suggest that dusky dolphins from Argentina and southern Africa recently separated from an ancestral Atlantic population and, since then, diverged without considerable gene flow. The inclusion of a few New Zealand samples further confirms the low levels of genetic differentiation among most dusky dolphin populations. Only the Peruvian dusky dolphin stock is highly differentiated, especially at mitochondrial loci, suggesting that major fluctuations in its population size have led to an increased rate of genetic drift. |
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