Question

Which chemical mutagen is a base analogue that replaces thymine?

Options

• Acridine dyes

• Mustard gas

• Nitrous acid

• 5-Bromouracil

Answer 1

5-Bromouracil is a base analogue chemical mutagen that replaces thymine during DNA replication. Due to its structural similarity to thymine but different pairing properties, it causes mispairing with adenine instead of the normal thymine-adenine pairing, leading to point mutations.