Question

Ultraviolet radiations cause mutations due to

• A. Formation of thymine dimers/ thymidine
• B. Deletion of base pairs
• C. Addition of base pairs
• D. Methylation of base pairs

Answer 1

Answer: (A)

Formation of thymine dimers/ thymidine

The signature mutation caused by ultraviolet light is a CC to TT mutation (C=cystosine T=thymidine), caused when a CC dimer is mispaired with two adenine bases during replication. Because of these mutations, the connection between ultraviolet damage to DNA and cancer is quite clear.

So, the correct answer is 'Formation of thymine dimers/ thymidine'.