Question

What do ‘Y’ and ‘B’ stand for in ‘YAC’ and ‘BAC’ used in the Human Genome Project (HGP)? Mention their role in the project.

Answer 1

The Human Genome Project (HGP), ‘Y’ stands for Yeast and ‘B’ stands for Bacterial. Together with the rest of the acronym, they represent Yeast Artificial Chromosomes (YACs) and Bacterial Artificial Chromosomes (BACs).

Role in the Human Genome Project:

• Cloning Vectors: Both YACs and BACs were used as specialised vectors to carry and clone large fragments of human DNA.
• DNA Amplification: Since human DNA is too large to be sequenced all at once, it was broken into smaller fragments. These fragments were inserted into YACs and BACs, which then replicated inside host cells (yeast or bacteria) to create many copies of the DNA for easier study.
• Large Insert Capacity: They were essential because they could accommodate much larger DNA segments than standard plasmids. YACs can carry up to 1 million base pairs, while BACs typically handle around 100,000 to 300,000 base pairs.
• Mapping and Sequencing: These clones were used to create a physical map of the genome, allowing scientists to determine the correct order of the DNA sequences.