DNA sequencing is performed by scientists in many different fields of biology. Many bioinformatics programs are used during the process of analyzing DNA sequences. In this lesson, students learn how to analyze DNA sequence data from chromatograms using the bioinformatics tools FinchTV and BLAST. Using data generated by students in class or data supplied by the Bio-ITEST project, students learn what DNA chromatogram files look like, learn about the significance of the four differently-colored peaks, learn about data quality, and learn how data from multiple samples are used in combination with quality values to identify and correct errors. Students use their edited data in BLAST searches at the NCBI and the Barcode of Life Database (BOLD) to identify and confirm the source of their original DNA. Students then use the bioinformatics resources at BOLD to place their data in a phylogenetic tree and see how phylogenetic trees can be used to support sample identification. Learning these techniques will provide students with the basic tools for inquiry-driven research.
This lesson can be completed with DNA sequence data (called chromatograms) that students generate, or they can use the pairs of "Unknown" chromatograms provided below. For each pair, students will use a "Forward" chromatogram and a "Reverse" chromatogram, representing sequence data from each strand of DNA.
To use this lesson with a single DNA sequence file per sample (instead of 2), use the handout and Powerpoint below.