The research described in this article was funded by National Institute of Justice grant 2015-NE-BX-K006 awarded to the University of North Texas Health Science Center and is based on the grantee report "Human Microbiome Species and Genes for Human Identification" by Bruce Budowle (NCJ 252942).
Humans transfer trace signatures of unique colonies of microbes on our skin to objects we touch. The tiny size of that signature make it difficult for investigators to identify an individual. Research now has made that identification more likely. Geneticist Bruce Budowle, director of the University of North Texas Center for Human Identification, realized that not only does human skin have a large number of bacterial cells on its surface, but that those cells would be transferred to an object when it is handled. Efforts to sequence human DNA from touch samples face the challenge of amplifying and analyzing highly dilute concentrations, but including an analysis of DNA from the bacterial cells could provide much more information from a single sample. Budowle's research team developed methods for identifying a core set of skin organisms consisting of ten species of bacteria, one fungus species, and one bacteria-attacking virus. Their methods combined the best features of current approaches used to identify microbial communities, which, for bacteria, have traditionally been based on either sequencing the single gene "16S," or entire genomes. They developed primers for 286 lineage-informative genomic sites, used them to amplify sample DNA, and then sequenced the products on a next-generation sequencing platform.