Post-doctoral researcher

phone: +32 (0)2 650 45 25

e-mail: Chedly.Kastally@ulb.ac.be

Research interests

Main interest

Genomic analysis of speciation and adaptation to its host plant in two sister species of leaf beetles (Coleoptera: Chrysomelidae).

Supervisor: P. Mardulyn

Adaptation and speciation are two key processes in the evolution of living organisms through which biological diversity is generated. For instance, the spectacular diversification of herbivorous insect is thought to be the result of specific adaptations to the large diversity of flowering plants.

This project aims to study the speciation and adaptation in herbivorous insects using two distinct approaches: firstly, at the molecular level, using high-throughput sequencing technologies, and secondly, at the phenotypic level, using breeding experiments.

The project focuses on two sister species of leaf beetles, Gonioctena quinquepunctata and Gonioctena intermedia, both specialists of the same two quite different host plants: the bird cherry, Prunus padus, and the European mountain ash, Sorbus aucaparia. What makes those leaf beetles especially interesting as models for our study is that many populations of each species are isolated from any other population with only one host-plant species available. Those populations have most likely developed independent adaptation to their host-plant and thus offer an interesting study case of parallel adaptation.

Other projects

Comparative study of various summary statistics commonly used in phylogeography to discriminate between demographic and historical scenarios.

Collaborators:  S. Dellicour, P. Mardulyn

Phylogeography aims to explain the current geographic distribution of genetic variation, within and between populations, by means of demographic and historical processes. Different approaches can be used to do so, one of which uses summary statistics to reduce the data sets and capture its relevant features in order to discriminate different geographical and demographic scenarios. However, there is still no general rule as to which and how many statistics should be used.

The aim of this project was to test several summary statistics commonly used in phylogeography in order to provide insights on the relevancy of each one of them when inferring demographic and historical scenarios. PhyloGeoSim is a coalescent-based simulator recently developed by Simon Dellicour using both demographic and spatial characteristics to simulate evolution of DNA sequences. Using this simulator, multiple demographic and evolutionary scenarios were computed, ranging from simple isolation by distance scenarios, population fragmentation and range expansion. The results show which statistics should be chosen to discriminate between each specific scenarios pair, and which ones are to be avoided, being redundant or uninformative.

Publications

Dellicour S, Kastally C, Hardy OJ, Mardulyn P (2014) Comparing phylogeographic hypotheses by simulating DNA sequences under a spatially explicit model of coalescence. Molecular Biology and Evolution.

Jossart Q, Wattier RA, Kastally C, Aron S, David B, De Ridder C, Rigaud T (2014) Genetic Evidence Confirms Polygamous Mating System in a Crustacean Parasite with Multiple Hosts. PLoS ONE 9(3), e90680.

Communications

Kastally C, Dellicour S, Mardulyn P (2012) Efficiency of Various Summary Statistics for the Comparison of Phylogeographic Scenarios and Case Study of a Leaf Beetle (Chrysomelidea).19th Benelux Congress of Zoology (Bruxelles, Belgique). Best master student poster award.

Educational background

1. •2012 – today: PhD in Evolutionary Biology (Université Libre de Bruxelles, Belgium)
   

2. •2010 – 2012: Master degree of Organisms Biology (Université Libre de Bruxelles, Belgium)
   

3. •2007 – 2010: Bachelor degree of Biological Sciences (Université Libre de Bruxelles, Belgium)