Practice question

Yeast artificial chromosomes were designed to replicate and segregate like native yeast chromosomes during mitosis and meiosis. Functionality requires three cis elements: autonomously replicating sequence acting as origin, centromere CEN conferring mitotic stability and ensuring proper spindle attachment and two telomeres protecting linear ends from degradation and fusion. URA3 and TRP1 provide selection, but structural resemblance relies on CEN, TEL and ARS combination. This tripartite core allows YAC to behave as an authentic linear chromosome, carrying megabase inserts and undergoing normal chromosome segregation in Saccharomyces cerevisiae.