“artificial chromosome”

: a genetically engineered bacterial chromosome that is used as a vector to clone DNA segments, that is introduced for cloning into a bacterium (E. coli) where it is maintained as a plasmid, and into which a segment of foreign DNA up to about 300 kilobases in length may be spliced for cloning —abbreviation BAC

: a chromosome that is used especially to clone DNA segments longer than those capable of being cloned in bacteria, that is introduced for cloning into a yeast of the genus Saccharomyces (S. cerevisiae), that contains a centromere, a telomere, and a replication initiation site suitable for use in the yeast, and into which a segment of foreign DNA up to about a million base pairs in length has been spliced for cloning —abbreviation YAC