Artificial chromosomes, uses thereof and methods for preparing artificial chromosomes

A method for amplifying nucleic acid, comprising:

• introducing a DNA fragment into a cell, wherein the DNA fragment comprises a selectable marker;
• growing the cell under selective conditions to produce cells that have incorporated the DNA fragment or a portion thereof that comprises the selectable marker into a chromosome;
• and
• identifying from among the resulting cells those that include a chromosome or fragment thereof with a portion that has undergone amplification.