show Abstracthide AbstractGymnosperms, which today comprise c. 800 species, are represented by just four groups (Cycads, Ginkgo, Gnetaleans and Coniferales (conifers). Yet they have a long and extensive fossil record which goes back to the Carboniferous (about 290 million years ago). They represent ecologically important group with far reaching economical impacts. Whilst much attention has been devoted to angiosperm genome structure and evolution, rather little has been expended on gymnosperms. Nevertheless, recent suggest that substantial differences exist between their genomes. Large genomes of gymnosperms are arranged in relatively few huge chromosomes supporting high linkage disequilibrium. Considering near absence of polyploidy, slow reproductive cycles and frequent diocecy gymnosperms have little opportunities to increase their genetic diversity by classical genetic mechanisms such as the meiotic recombination. The aim of this project is to explore gymnosperm chromosomes in a new dimension - that of genome structure and the mechanisms by which their karyotypes are shaped.