Conclusion: Incorporation of bromouracil followed by mispairing leads to a TA-*■ CG transition mutation.

^ If 5-bromouracil pairs with adenine, no replication error occurs.

4 17.19 5-Bromouracil can lead to a replicated error.

17.20 Chemicals may alter DNA bases, (a) The alkylating agent ethylmethanesulfonate (EMS) adds an ethyl group to guanine, producing 6-ethylguanine, which pairs with thymine, producing a C-G : T-A transition mutation. (b) Nitrous acid deaminates cytosine to produce uracil, which pairs with adenine, producing a C-G : T-A transition mutation. (c) Hydroxylamine converts cytosine into hydroxylaminocytosine, which frequently pairs with adenine, leading to a C-G : T-A transition mutation.


Original base


Modified base

Pairing partner

Type of mutation


Was this article helpful?

0 0

Post a comment