‘Twin Sister’ mechanism prevents formation of genetic mutations

Twenty thousand hits per day — that’s the average dose of damage sustained by the genes within each cell of our body. How are innumerable mutations avoided? In a new study, researchers have proved the existence of a vital repair mechanism used by cells to correct this damage and showed that it’s responsible for about 85% of what are termed “last-resort” repairs. Genes can be damaged by a variety of factors, such as ultraviolet light, cigarette smoke, or certain types of viruses. Such damage, if left unrepaired, can cause mutations, which can lead to disease. The “first resort” for genetic repair is most often a mechanism that works on an “all or nothing” basis: when unable to precisely correct the damage, it stops in its tracks, leading to what can be an even more harmful effect ? the death of the cell. Fortunately, nature has provided cells with two alternative, last-resort repair systems that can take command when the first rescue mechanism fails.