In the field of forensics, scientists can tell the story of how, when and where certain outdoor crimes occurred by analyzing the soil and its contents.  One of its contents includes DNA.  DNA from the victim or suspect can be recovered from the soil at a crime scene. In addition, DNA from other animals can be recovered in these same locations as animals slough off cells from their skin and waste.

According to a recent study in Molecular Ecology, scientists have shown that DNA fragments found in the soil can not only determine what species occupy a given area, but also how many individuals from each species occupy that area.  The University of Copenhagen team devised a way to roughly estimate the number of individuals of each species found in a particular area  by measuring the quantity of DNA found from each species present. Scientists can now use this information to survey the biodiversity and ecological relationships that exist between different species in an area.

Not only have the scientists recovered DNA from animals currently present in a given location, but they have also recovered DNA from animals that once, but no longer occupy that same location.  Perhaps digging deeper can reveal animals that once occupied an area thousands of years ago.

Now I wonder if I take soil from my backyard, will I find DNA remnants of rabbits, snakes, mice or raccoons? And will I find out which animals have been coming to my yard in droves while I was away?  It should be an interesting experiment.

For more information go to:

http://www.nature.com/news/2011/110923/full/news.2011.556.html?s=news_rss

Andersen, K. et al. Mol. Ecol. http://dx.doi.org/10.1111/j.1365-294X.2011.05261.x (2011).