Whole genome sequencing to identify candidate genes governing social behaviour in Dictyostelium discoideum

Although the Darwinian idea of ‘survival of the fittest’ is central to our understanding of the diversity of life on this planet, the evolution and maintenance of cooperative behaviour remains a conundrum. This is because when cooperating individuals perform some sort of costly act to help one another, they run the risk of disruptive cheaters that do not pay their fair share of the cost. In other words, if cheating is a better strategy, how is cooperative behaviour maintained within populations.
To address these problems, we use a simple system for the study of cooperative behaviour, the soil dwelling social amoeba D. discoideum. Under favourable conditions, D. discoideum amoebae exist as single celled individuals that grow and divide by feeding on bacteria. Upon starvation, however, up to 100,000 amoebae aggregate and cooperate to make a multicellular fruiting body consisting of hardy spores supported by dead stalk cells. Stalk cells thus sacrifice themselves to help the dispersal of spores, raising the question of why selection does not lead to unchecked cheating by individuals that do not pay their fair share of the cost of stalk production. Indeed, we have recently found that even within a small number of different D. discoideum strains, different social strategies, including facultative partner specific cheating and coercion, could be detected.
However, the key will be to extend this work to address patterns of genetic variation at the molecular genomic level in natural populations.
Through this PhD studentship we aim to reach this important goal. The project will have 3 stages:
1. Genome sequencing: Whole genome sequence data will be generated for many different naturally occurring D. discoideum isolates
2. Bioinformatic analysis of this sequence data: This will allow you to test whether genetic variation is associated with patterns of phenotypic variation. Through this you will identify ‘social genes’ and the potential role of all of these genes as generators of biodiversity. Finally, these data will allow broader questions regarding the selective forces driving genome evolution and the emergence of social traits to be addressed.
3. Molecular genetics: Using cutting edge developmental genetics techniques (e.g. transformation, knockouts and forced expression of functional variants) you will test hypotheses about the functional consequences of sequence variation on social behaviour.
In summary, this project will address major questions in evolutionary, developmental and environmental ecology. It will utilise hugely multidisciplinary approach by combining next generation sequencing, bioinformatic exploration of sequence variation, together with molecular and developmental genetics. Consequently it will undoubtedly provide an unprecedented opportunity for training in multidisciplinary approaches to biological questions.