In somatic cells, if a base is mismatched in one new daughter strand during DNA replication, and is not repaired, what fraction of the DNA duplexes will have a permanent change in the DNA sequence after the second round of DNA replication?

Question

Quizplus · Accepted Answer

After the first round of DNA replication, one of the two daughter strands will have a mismatched base. In the second round of replication, the strand with the mismatch will produce one mutated strand and one correct strand (since the original template strand is correct), while the original correct strand will produce two correct strands. Thus, out of the four strands produced in the second round, only one will have a permanent change, making the fraction 1/4.

In Somatic Cells, If a Base Is Mismatched in One