The research method was constructed through a review of the Wild Life of Our Homes citizen science project conducted by the Your Wild Life lab, located in North Carolina. The project involved volunteer scientists collecting dust samples from some 1,000 houses throughout the U.S. In total, homes across 47 states were swept.
The collected dust samples were taken back to laboratories for DNA analysis. The goal was to identify the different microorganisms found in typical homes. One thing of interest was that the various types of fungi varied considerably throughout different states.
This enabled a research team to devise a statistical model using computer software, so that they could predict where any given dust sample came from. The model is not only capable of differentiating between states, it can accurately go down to the regional level. In some cases, the model is able to pinpoint where a sample has come from within a 35 mile radius. The worst case, after multiple tests was run, was to pinpoint a sample within a radius of 645 miles. The typical level of accuracy is within 143 miles. It is hoped that further modelling will allow the accuracy to be improved.
To achieve this, the scientists analyzed the fungal taxa present in the different dust samples using advanced molecular screening methods. This involves either scraping off fungal hyphae or filtering a suspension and running molecular assays like PCR (polymerase chain reaction.) This method is used to amplify a single copy or a few copies of a piece of DNA across several orders of magnitude.
The implications of the study is that the method could be used as a forensic biology tool for use in law enforcement or a means for archaeologists to trace the origin or even the age of remains.
The study was a collaboration between scientists based at the North Carolina State University and the University of Colorado, Boulder. The research has been published in the journal PLOS One, in a paper titled “Fungi Identify the Geographic Origin of Dust Samples.”