Mistakes and misinterpretation are common incidents. We are usually aware of those we can see, or hear, such as a bird flying into an undetected window or a person who has misunderstood a question. Yet, mistakes are also a recurring phenomenon at a level no living being can readily observe: the molecular level. Take, for instance, mutations that occur in an organism's DNA. Though the evolution of species may sometimes thrive on such flaws, they are also frequently the source of serious drawbacks. This is why, over time, Nature has devised different systems whose role is to detect mistakes in DNA and offer a means to fix them. Until recently, repair systems had only been considered on double-stranded DNA where the untouched strand acts as a template to re-establish an error found on the second. But when damage is found on single-stranded DNA, what happens? Is it even possible to make amends? Against all odds: yes. Such a repair system involves a protein that has been coined HMCES, which is found throughout the three domains of life, and even in certain viruses it seems. Read more