“…Human artificial chromosomes (HACs) are presently constructed to understand how chromosomes work and which sequence elements are required for stability and function. [1][2][3][4][5][6] Ultimately, HACs could become a safe and efficient gene transfer tool circumventing DNA-induced cell cycle arrest, replicative loss, integrative repair, and silencing. 7,8 In a series of HAC transfection experiments we recently established that the inclusion of large genomic DNA (100 kb) capped by telomeric repeats improves the de novo formation of HACs based on cloned centromere DNA, making HAC formation more efficient than the conventional procedure to obtain stable clones via integration into host chromosomes (Schindelhauer et al, in preparation).…”