This Practical Guide introduces the idea of computers as tools to help understand aspects of biology. In particular, it looks at how DNA sequences can be used to identify specific organisms, why this is important in the food industry, and how this can be used to help de- tect food fraud. Analyses are run online using sequence data from the 4273pi project website: 4273pi.org.
This Guide introduces a popular Web-based tool for searching biological sequence databases, and shows how to identify different spe- cies based on their specific DNA sequences – their ‘barcodes’. On reading the Guide and completing the exercises, you will be able to: i) explain what is meant by DNA barcoding; ii) search biological sequence databases using the online program BLAST; iii) judge the reliability of database-search results in terms of their statistical significance; and iv) evaluate the biological implications of search results with reference to food safety.