Bacterial artificial chromosome (BAC)

Definition

A bacterial artificial chromosome (BAC) is a vector used to clone DNA fragments in bacteria, enabling the manipulation of large segments of genetic material. BACs are derived from the F plasmid of E. coli and can carry inserts of 100-300 kilobases, making them valuable tools for mapping genomes and sequencing projects, particularly in genomic studies and the Human Genome Project.

5 Must Know Facts For Your Next Test

1. BACs can hold larger DNA fragments compared to other vectors, allowing for more extensive genomic mapping and analysis.
2. The use of BACs was crucial in the Human Genome Project, facilitating the sequencing of complex genomes.
3. BACs are stable and replicate within bacterial cells without rearranging the inserted DNA, preserving the integrity of large genetic sequences.
4. Unlike traditional plasmids, BACs utilize the F plasmid origin of replication, which contributes to their ability to maintain larger DNA inserts.
5. BACs are often used in constructing genomic libraries that help researchers identify and isolate specific genes.

Review Questions

• How does the structure and capacity of bacterial artificial chromosomes (BACs) contribute to their effectiveness in genomic mapping?
  • BACs are designed to carry large DNA fragments of 100-300 kilobases, which is significantly more than traditional plasmids. This capacity allows researchers to clone and analyze substantial sections of genomes at once, making BACs highly effective for genomic mapping. The stability of BACs ensures that these large inserts remain intact throughout replication, facilitating accurate mapping and analysis during sequencing projects.
• Discuss the advantages of using bacterial artificial chromosomes (BACs) over smaller vectors in genomic studies.
  • BACs provide several advantages over smaller vectors, including their ability to carry larger inserts without losing genetic information. This capability is essential when working with complex genomes that contain many genes and regulatory regions. Additionally, BACs maintain the integrity of the cloned DNA because they replicate stably in bacterial cells. This stability reduces the risk of rearrangements during propagation, making BACs a preferred choice for constructing comprehensive genomic libraries.
• Evaluate the role of bacterial artificial chromosomes (BACs) in advancing our understanding of genetic diseases through genomic research.
  • BACs have played a critical role in advancing our understanding of genetic diseases by enabling researchers to isolate and study specific genes associated with various conditions. By constructing genomic libraries with BACs, scientists can identify mutations and variations within genes that may contribute to disease phenotypes. This targeted approach not only aids in gene identification but also enhances our ability to develop potential therapies by elucidating gene function and interactions within broader genomic contexts.

Related terms

Vector: A vehicle, often a plasmid or virus, used to transfer genetic material into a host cell.

Cloning: The process of making multiple identical copies of a particular DNA sequence or organism.

Genomic Library: A collection of DNA sequences representing the entire genome of an organism, stored in vectors like BACs for analysis.