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Genetics of Ecological Speciation in Birds

Final Report Summary - GENES AND SPECIATION (Genetics of Ecological Speciation in Birds)

Project objectives

Genetics of Ecological Speciation in Birds is a collaborative research programme on the genetics of ecological speciation, using birds as models. We use population genetics and candidate gene approaches, and follow up with additional molecular techniques such as expression analyses using microarrays. We gather molecular evidence to confirm or refute the occurrence of sympatric speciation in two avian radiations, and initiate the search for genetic regions under selection, to determine the genetic bases of adaptation and ultimately speciation. The long-term aim is to identify genes underlying the evolution of bill size/shape. Bill morphology is an important trait in resource-driven bird diversification, and therefore the establishment of links between phenotype-fitness-genotype will advance significantly our understanding of the speciation process.

The International Research Staff Exchange Scheme (IRSES) programme Genes and Speciation has allowed us to achieve mutual benefits from exchanging expertise on novel laboratory innovations and to increase the efficiency of each lab by exchanging experience and sharing available infrastructure. A symmetric exchange of staff and resources provided the best way to achieve the highest degree of complementarities and synergies between the partners. Lab work was taken place in 2009-2010 and included population genomics with neutral markers, candidate gene approaches and microarray analyses.

The major tasks were:
- (i) Robust phylogenies and detailed description of the phylogeographical patterns in both study systems based on nuclear sequence data;
- (ii) Understanding of recent population events by using microsatellite analyses;
- (ii) Characterisation of the genetic architecture of ecologically and evolutionary important traits (such as bill and body size) using candidate gene screening;
- (iv) Description and understanding of the level and dynamics of linkage disequilibrium in the study systems by densely mapping two chromosome regions;
- (v) To reveal the genetics of population divergence and speciation by combining pyrosequencing, microarrays and multilocus SNP genotyping;
- (vi) Understanding the degree of genetic variability at the major histocompatibility complex (MHC).

Exchange have included Pretoria, South Africa, and Lund, Sweden, in 2009; Lund and Cape Town in 2009 and 2010; Cape Town and Lund in April 2010; Lund/Sheffield, United Kingdom, and Pretoria September/October 2010; Cape Town and Pretoria September/October 2010; Lund and Pretoria October 2010; Lund and Cape Town October 2010; Exchange between Cape Town and Lund in 2010.

During December 2009, genetic data for the Neospiza/Serinus system was evaluated as a part of Martin Stervander's MSc thesis at Lund University under the supervision of Bengt Hansson (main) and Martim Melo (co-supervisor). The MSc thesis had the title "Tracking genetic divergence in Gulf of Guinea finches - strong support for sympatric speciation" and was presented and passed with distinction the 11th February 2010.

During March 2010 similar analyses was conducted for the Nesospiza study system, and constituted a part of Alexandra Jansen van Rensburg's MSc at University of Pretoria. The MSc thesis was planned to be completed by the end of 2010 and was completed in February 2011; and has the title "Genetic variation underlying the adaptive radiation of Nesospiza buntings at the Tristan da Cunha archipelago". Paulette Bloomer was main supervisor and Peter Ryan (University of Cape Town) and Bengt Hansson (Lund University) co-supervisors.

As a direct outcome of the project, Martin Stervander was assigned as a PhD-student at Lund University in March 2010 under the supervison of Bengt Hansson and Staffan Bensch (Lund University).