Since the development of the synthetic theory of evolution (Huxley 1942), researchers in the field of evolutionary biology have mainly worked on two different time scales: microevolution, i.e. the evolution of populations below the species level (such as population genetics, phylogeography and quantitative genetics), and macroevolution, i.e. the evolution of species or clades to a higher taxonomic level (such as phylogenetics, paleobiology and biogeography). Our understanding of the evolutionary mechanisms from micro to macroevolution is limited by the fact that there are few studies integrating different time scales (Uyeda et al. 2011, Rolland et al. 2018).
Do factors important for the differentiation/divergence among populations also act on the divergence between species? The internship aims to answer this question with unique data. Datasets encompassing both micro and macro-evolutionary timescales are particularly scarce (Rolland et al. 2018), as large numbers of individuals need to be sampled at the population level and at the species level. In collaboration with N. Salamin, we sequenced ~ 4,000 regions of nuclear DNA for more than 800 individuals in 53 species of Geonoma palms on an altitudinal gradient ranging from sea level to over 3,000 m in the rainforests of Central and South America. For these data, the trainee will calculate the genetic distance for each gene between each pair of individuals (e.g. using PLINK, Purcell et al. 2007). This genetic divergence is a continuous measurement, which does not depend on the concept of species because it will be calculated between individuals, between populations and between species. It is then possible to test hypotheses on the origin of the genetic divergence, such as the calculation of the contribution of geographical distance (Isolation By Distance, IBD) and environmental factors (Isolation by Environment, IBE) to the genetic divergence. The geographic distances will be calculated directly on the map with GIS softwares, and the environmental climate will be extracted for each occurrence using data from Worldclim (Hijmans et al. 2005). This method has already been used on Caribbean anolis lizards (Wang et al. 2013). The internship will build on work already carried out on Geonoma (Loiseau et al. 2019). Other main collaborator of the project: Nicolas Salamin (UNIL, Switzerland).
Hijmans, R. J., Cameron, S. E., Parra, J. L., Jones, P. G., & Jarvis, A. (2005) Very high resolution interpolated climate surfaces for global land areas. International Journal of Climatology: A Journal of the Royal Meteorological Society, 25, 1965-1978.
Huxley, J. (1942) Evolution. The modern synthesis. Evolution. The Modern Synthesis.
Loiseau, O., Olivares, I., Paris, M., de La Harpe, M., Weigand, A., Koubinova, D., et al. (2019) Targeted capture of hundreds of nuclear genes unravels phylogenetic relationships of the diverse Neotropical palm tribe Geonomateae. Frontiers in plant science, 10, 864.
Purcell, S., Neale, B., Todd-Brown, K., Thomas, L., Ferreira, M. A., Bender, D., et al. (2007) PLINK: a tool set for whole-genome association and population-based linkage analyzes. The American journal of human genetics, 81, 559-575.
Uyeda, J. C., Hansen, T. F., Arnold, S. J., & Pienaar, J. (2011) The million-year wait for macroevolutionary bursts. Proceedings of the National Academy of Sciences, 108, 15908-15913.
Rolland, J., Silvestro, D., Litsios, G., Faye, L. and Salamin, N., (2018) Clownfishes evolution below and above the species level. Proceedings of the Royal Society London B. 285, 20171796.
Wang, I.J., Glor, R.E., & Losos, J.B. (2013) Quantifying the roles of ecology and geography in spatial genetic divergence. Ecology letters, 16, 175-182.
This 2nd year master internship will be funded (~ 550 € / month) from January to June 2022 (dates to be discussed) and will be supervised by Jonathan Rolland (researcher at the CNRS) at the Laboratoire Evolution et Diversité Biologique in Toulouse (FRANCE). Candidates willing to apply to a PhD fellowship for the following year are welcome.
Please send me your CVs and / or cover letter now to [email protected] Candidates with some programming experience will be appreciated.