YACs

YACs commonly refers to Yeast Artificial Chromosomes, a class of cloning vectors developed for genetic research. YACs are used to clone very large DNA fragments, typically hundreds of thousands to about a million base pairs in length, enabling researchers to construct libraries that span sizable genomic regions. A typical YAC contains essential yeast chromosome elements—a centromere for stable segregation during cell division, telomeres at both ends, and an autonomously replicating sequence that allows replication in yeast—combined with a cloning site for foreign DNA and a selectable marker. Because of their capacity to carry large inserts, YACs were instrumental in early genome mapping and sequencing efforts, including applications that hosted substantial human DNA fragments to facilitate physical mapping and analysis of gene organization.

The widespread use of YACs declined after the rise of bacterial artificial chromosomes (BACs), which offered greater stability and easier handling in bacterial hosts. Despite this shift, YACs remain of historical importance in genome projects and are still encountered in certain specialized research contexts and educational settings, where large-clone cloning strategies are explored.

Outside genetics, the acronym YACs is not standardized and can be used informally to denote various organizations, committees, or projects that share the initials YAC. Because meanings can vary by domain and locality, the specific interpretation of YACs should be inferred from the surrounding context.