MOLECULAR ZOOLOGY LAB
Head: Dr Peter Teske, University of Johannesburg, Auckland Park 2006, Johannesburg, South Africa; Email: firstname.lastname@example.org
This recently founded research group uses genetic tools to study aquatic animals, with a specific focus on the marine biogeography of southern Africa.Student Projects:We invite applications for the following research projects. Interested South African or international students should please contact the laboratory at email@example.com. Bursary support is available for all projects.Masters or PhD project: Adaptive divergence (aquaculture) - - from mid-2014 or early 2015Adaptive divergence in a coastal crab across the Atlantic/Indian Ocean biogeographic disjunction. This projects involves the rearing of crab larvae from South Africa's west coast under a range of temperatures, and recording their survival. These data will then be compared with previously generated data from a south coast population to determine whether the two evolutionary lineages of this species are adapted to different temperature regimes that characterise their respective habitats. The project can be upgraded to a PhD by rearing larvae from a third site (south-west coast) where both lineages occur in sympatry, and generating genetic data to distinguish them. Students should have experience in physiological work and/or aquaculture, and will be based in Durban for the duration of the laboratory work.
Photo: Robert Harcourt
Teske PR, Sandoval-Castillo J, Waters J, Beheregaray LB (2014)
Can novel genetic analyses help to identify low-dispersal marine invasive species? Ecology and Evolution.
The genetic study of introduced species is presently dominated by analyses that identify signature of recent colonisation by means of summary statistics. Unfortunately, such approaches cannot be used in low-dispersal species, in which recently established populations originating from elsewhere in the species' native range also experience periods of low population size because they are founded by few individuals. We tested whether coalescent-based molecular analyses that provide detailed information about demographic history support the hypothesis that a sea squirt whose distribution is centered on Tasmaniaq was recently introduced to mainland Australia and New Zealand. Methods comparing trends in population size were no more informative than summary statistics, likely because of recent intra-Tasmanian dispersal. However, estimates of divergence between putatively native and introduced populations provided information at a temporal scale suitable to differentiate between recent introductions and ancient divergence, and confirmed that all three non-Tasmanian populations were founded during the period of European settlement.
Teske PR, Papadopoulos I, Barker NP, McQuaid CD, Beheregaray LB (2014)Mitonuclear discordance in genetic structure across the Atlantic/Indian Ocean biogeographical transition zone. Journal of Biogeography 41: 293-401.
Many organisms with ranges spanning multiple biogeographical regions are genetically sructured across the transition zones on the basis of mitochondrial DNA, while others appear to be genetically homogenous. No clear link has been found between the presence and absence of genetic structure and species' dispersal potential. We identified clear biogeography-linked nuclear DNA genetic structure in a coastal invertebrate that has no mtDNA-based structure. This result stresses the importance of revisiting single-locus data sets by means of multi-locus genetic approaches before any conclusions can be drawn about the role of biogeographical transition zones in driving genetic structure.
Teske PR, Papadopoulos I, Barker NP, McQuaid CD (2013)Disperal barriers and stochastic reproductive success do not explain small-scale genetic structure in a broadcast-dispersing mussel. Marine Ecology Progress Series 482: 133-140.
Females of the marine mussel Perna perna are genetically structured between bays and the open coast, but we found no strong support for two commonly invoked pre-settlement factors that could explain small-scale genetic structure within coastal regions. Genetic heterogeneity could not be explained by nearshore circulation resulting in asymmetrical dispersal, nor did we find evidence for temporal changes in population structure resulting from chance mating success. While we cannot presently explain the mechanism that has driven genetic structure in female P. perna, our study points to a role for species- and gender-specific adaptive constraints in driving genetic structure.
Teske PR, Zardi GI, McQuaid CD, Nicastro K (2013)
Two sides of the same coin: extinctions and originations across the Atlantic/Indian Ocean boundary as a consequence of the same climate oscillation. Frontiers of Biogeography 5: 48-59.
We discuss a model of range extension followed by divergence, in which the same climate oscillations that resulted in the extinction of coastal species in south-western Africa also sowed the seeds of new biodiversity.