Researchers at the California Institute of Technology have devised a new method to create biochemical circuits with synthetic DNA that allows for larger circuits than previously created. A very important point of this new technique is that the DNA molecules, comparable to electronic transistors, are fully programmable! To demonstrate this method, the researchers created a circuit using 74 different DNA molecules, the largest they have made, to calculate the square root of any number up to 15 (or 1111 in binary) and then round that value down to the nearest integer. Just input a number less than fifteen, as a molecule of DNA, wait for about 10 hours, and you’ll have your answer.
The goal of research into DNA computers, like this, is not to replace electronics, but to learn more about life, by, hopefully, one day making a biochemical system as complex as life itself. So no, you cannot play Crysis on it.