All animal species carry versions of certain shared genes. The information in these genes is carried in long sequences of four types of nitrogen bases, like a language consisting of four letters, and the particular sequences of nitrogenous bases can be reliably used to identify individual species. If each of the four nitrogenous bases in a sequence is represented by a different coloured line, then the unique sequence for each species can be presented as a sort of four-coloured bar code, not unlike the bar codes that identify every unique product in store.
In this study, we collected the DNA from several dozen different ant specimens, from over a dozen presumed species, made millions of copies of the segment of DNA that we were interested in, cleaned and purified it, determined the sequence of nitrogenous bases in each sample, and then compared the sequences (bar codes) to those already published in a database. Each step required some experimentation and practice.
