Question

Which among the following is incorrect with reference to Yeast Artificial Chromosomes?

• A. YACs have ORS, Telomere and Centromere
• B. They are used for physical mapping of complex genomes
• C. They can be used to express eukaryotic proteins that require post translational modifications
• D. YAC do not favor cloning of large fragments of DNA

Hint:

• Yeast Artificial Chromosomes (YACs) Cloning vectors that replicate as linear chromosomes in yeast.
• Key features ARS (origin), CEN (centromere), TEL (telomeres), selectable markers.
• Main advantage Can clone very large DNA inserts (hundreds of kilobases to megabases).
• Used for genomic libraries of complex genomes, physical mapping, and expressing large genes or eukaryotic proteins.

Answer 1

The Correct Option is D

Yeast Artificial Chromosomes (YACs) are vectors used in molecular biology to clone DNA fragments. They have certain key features and uses, outlined as follows:

• Key Components: YACs contain an origin of replication (ORS), telomeres, and a centromere. These components are necessary for the replication and stable maintenance of the YAC in yeast cells.
• Usage: YACs are employed for the physical mapping of complex genomes. They are instrumental in constructing large DNA libraries due to their ability to carry large fragments of DNA, often exceeding hundreds of kilobases.
• Protein Expression: YACs can be used to express eukaryotic proteins that require post-translational modifications. The yeast system provides the machinery needed for these modifications, which are essential for the proper function of many eukaryotic proteins.
• Cloning Capability: Regarding the statement that "YAC do not favor cloning of large fragments of DNA": This is incorrect. YACs are specifically designed to accommodate and clone large DNA fragments, which is one of their principal advantages over other types of vectors.

Thus, the incorrect statement with reference to Yeast Artificial Chromosomes is that "YAC do not favor cloning of large fragments of DNA."