When DNA repair goes wrong

摘要

Mistakes in the DNA sequence are constantly being repaired, but some repair mechanisms are themselves error-prone. One, called break-induced replication (BIR), is initiated at sites at which both DNA strands are broken, and mimics the process of DNA replication. However, its rate of frameshift mutation - a type of mutation that almost always results in loss of gene function - is up to 2,800 times higher than that of normal replication.