Tracking down the poo-petrator. A Pennsylvania complex is requiring its residents’ canines to undergo DNA testing so any dog poop can be traced back and their owner held accountable. The testing service – which uses 16 genetic markers to identify a match and is so accurate that the probability of another dog having the same genetic profile is often as high as one in 44 sextillion – cuts dog waste by about 75%. And there are other indirect benefits such as preventing the spread of disease and keeping toxins out of the water.