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Understanding the evolutionary origin of biological diversity

Final Report Summary - SPECIATION (Understanding the evolutionary origin of biological diversity)

The aim of this Network was to train nine young scientists to PhD level in the biological disciplines needed to understand the evolutionary origin of biological diversity. This understanding is critical to the proper management of biodiversity, especially at a time of rapid environmental change. Our approach was to select powerful model systems with which to investigate the process of speciation and related mechanisms and to apply modern techniques from quantitative and behavioural genetics, molecular ecology and environmental genomics. Students were to receive advanced training through their projects, through institutional training programmes, through workshops and conferences organized by the Network and from Visiting Scientists. We also planned for our students to be seconded to non-academic institutions representing end-users of our research and potential employers, including a commercial laboratory, a museum, a conservation organization and a publisher.
The Network had four participant Universities, Sheffield (USFD), Groningen (RuG), Jyvaskyla (JYU) and St Andrews (USTAN) and 8 Associated Partners. It held an introductory conference on ‘Challenges in Speciation Research’ and a closing conference on ‘Progress in Understanding the Origins of Biodiversity’, both of which were open to external participants. Our Early Stage Researchers (ESR) all presented results at the final conference. In addition, four workshops were held, providing training in subject-specific and transferable skills. These were also open to external participants. In total, the network provided 556 researcher-days of external participation in addition to 323.1 of the planned 324 person-months of ESR training. The Network organized a symposium on ‘Speciation by natural vs sexual selection’ at the European Society for Evolutionary Biology XIII Congress in Tübingen in August 2011.

The core research objective was to achieve the understanding of biological diversity that is essential for its proper management at a time of rapid environmental change. To this end, we had three focal research areas:
1. The genetics and genomics of reproductive isolation.
2. The behavioural mechanisms of speciation
3. The evolutionary and ecological drivers of diversification
The Early Stage Researchers involved in the project used a wide range of techniques, including quantitative analysis of behaviour, genetic and genomic analysis and theoretical modelling. These approaches were applied to the following model systems:
1. Nasonia wasps (RuG)
2. Drosophila fruit flies (USFD, JYU, USTAN)
3. Chorthippus grasshoppers (USFD)
4. Pygospio marine worms (JYU)
5. Theoretical and comparative analysis (RuG)
Each project is described on our web site and contact details are provided there.

Some of the highlights of progress in these projects so far are (ESR names in bold):
• allopatric Drosophila montana populations have been found to exhibit premating and postmating reproductive isolation, and there appears to be asymmetry in both (WP3). See: Jennings, J.H. Mazzi, D., Ritchie M.G. and A. Hoikkala. 2011. Sexual and postmating reproductive isolation between allopatric Drosophila montana populations suggest speciation potential. BMC Evolutionary Biology 11:68.
• Four developmental genes have been identified in Pygospio and polymorphism in mode has been analysed (WP9). See: Kesäniemi, J.E. E. Geuverink, and K. E. Knott. 2012. Polymorphism in developmental mode and its effect on population genetic structure of a spionid polychaete, Pygospio elegans. Integrative and Comparative Biology, 52 (1): 181-196
• ESR Elina Immonen completed a playback study, examining gene expression changes in response to song in Drosophila melanogaster females. This exciting study was published in Proceedings of the Royal Society (Vol. 279, pp. 1359-1365). (WP7)
• A QTL analyses for diapause response in Nasonia vitripennis was performed by ESR Silvia Paolucci, using phenotypic data collected in April-May 2010 and genotypic data (microsatellite markers) collected in October 2010- January 2011. The analysis indicates that genomic regions involved in diapause variation are present in chromosome 1 and chromosome 5 of the Nasonia genome (WP11).
• The study on latitudinal variation in diapause induction in Drosophila montana showed that local adaptation may occur even in the presence of high gene flow, when selection for locally adaptive life-history traits is strong. The diapause response was found to be triggered by external, environmental cues. See: Tyukmaeva, V.I. Salminen,T.S. Kankare, M., Knott, E. & Hoikkala, A. 2011. Adaptation to a seasonally varying environment: a strong latitudinal cline in reproductive diapause combined with high gene flow in Drosophila montana. Ecology and Evolution 1, 160-168 (WP10).
• Genetic variation in potential prezygotic isolation traits, including mating behaviour (male courtship behaviour, female mate discrimination and male wing vibration) and chemical profiles for communication in sexual selection (cuticular hydrocarbon) of Nasonia species has been described and quantitative trait locus analysis of these traits is nearing completion (WP4, ESR Wenwen Diao)
• ESR Allan Debelle has successfully shown that altering sexual selection intensity in long-term experimental evolution lines of Drosophila pseudoobscura had an significant impact on male mating success and female preference (WP6).

We expect that each research project will result in three or more publications in major international journals, representing a substantial contribution to knowledge and understanding of the generation of biological diversity. To date, 11 papers have been published, including a major commissioned review on which all Network members were authors: The Marie Curie SPECIATION Network. What do we need to know about speciation? Trends in ecology & evolution, 27(1):27–39, 2012.

All nine ESR registered for PhD degrees in their home institutions where they received day-to-day supervision and attended training courses which supplemented the training provided through the network. Each ESR had at least one supervisor from another participant institution. ESR have undertaken a total of 32 secondments, including 17 visits to Associated Partners. For example, four ESR have worked with commissioning editors for commercial publishers at major international conferences and two have assisted a commercial software company that works on behavioural monitoring systems with their product development. To date, three ESR have submitted PhD theses. Four are expected to do so in the coming year. Two ESR left the network before completing their contracts and one had only a short-term contract. In all three cases, they benefitted from their training with us and are now undertaking PhD programmes elsewhere. One ESR will obtain an MSc degree from her host institution and has also moved to a PhD programme elsewhere. The most important output of the network is this group of highly trained young scientists with excellent subject-specific skills and also with a broad vision of the benefits of international co-operation and the opportunities for scientists to work outside the university environment.

For more information, contact the coordinator, Professor Roger Butlin (r.k.butlin@shef.ac.uk) or visit our web site: https://sites.google.com/site/itnspeciation/