Molecular Mechanisms of Ring Chromosome Formation and Instability

Ring chromosome (RC) formation is a result of “rescue” chromosomes with DNA double-strand breaks. The mechanisms of formation of RCs are not limited to incorrect repair of DNA double-strand breaks (DSBs), but also include recombination errors that lead to the occurrence of such breaks. The main mechanisms of instability of RCs in cells are also associated with meiotic and mitotic recombination. The chapter discusses the main causes and mechanisms of the occurrence and instability of RCs, as well as possible factors affecting the degree of such instability of RCs in vitro and in vivo.