On July 6th 2017, Atef Sahli, Ph.D. candidate in forest sciences at Univ. Laval and member of the Canada Research Chair in Forest Genomics, successfully presented his thesis entitled “Copy number variations in white spruce gene space”. Atef showed the importance of an largely uncharacterized type of large-size genetic polymorphism across the white spruce genome, namely orthologous copy number variations of genes, beyond the strict diploidy of spruces. These variations can influence genes functionality, as well as different phenotypic traits in animal and annual plant species. Using the genotyping results of thousands of samples for thousands of genes, Atef estimated the abundance of these polymorphisms in the white spruce gene space. In particular, he demonstrated that mutation rates were high, with frequent transmission distortions affecting a large number of genes. The evaluation committee consisted of Jean Bousquet, research director (Canada Research Chair in Forest Genomics, Univ. Laval), John Mackay, research co-director (Dept. of Plant Sciences, Univ. of Oxford), Simon Joly, external reviewer (Institut de recherche en biologie végétale and Dept. of Biological Sciences at the Univ. of Montreal), François Belzile, internal reviewer (Faculty of Agriculture and Institute for Integrative Systems Biology, Univ. Laval), and Ilga Porth, internal reviewer (Canada Research Chair in Forest Genomics, Univ. Laval). The defense was chaired by Nancy Gélinas, vice-dean of studies at the Faculty of Forestry, Geography and Geomatics of Univ. Laval. Congratulations Atef!