Featured in PASCO’s Advanced Biology through Inquiry Teacher Guide
This manual features 22 challenging, standards-based, inquiry lab activities for AP, IB, and honors programs.
Students analyze the DNA and protein sequences of beta globin of five mammalian species to determine their evolutionary relatedness.
In this activity, students employ the same tools used by research scientists all over the world: online databases that allow comparison of DNA and protein sequences across species. Students compare 100-nucleotide sequences of the Hemoglobin B gene (HBB) to determine the relatedness of five different mammals. HBB codes for the beta chain of the hemoglobin protein; this chain is also referred to as beta globin.
In just the first decade of the 21st century there has been an exponential increase in the number of species that have had their gene and protein sequences identified, and this information is readily available and searchable online. One such database is managed by the National Library of Medicine (NLM), part of the National Center of Biotechnology Information (NCBI). Using search tools such as BLAST® (Basic Local Alignment Search Tool), researchers can identify, from an unknown segment of DNA or a polypeptide, the precise genus and species from which it originated.
Importantly, BLAST can locate regions of genomes or proteomes similar to a given segment of interest, thus providing information about the “alignment” of species, that is, their evolutionary relatedness. Other databases can be accessed from NCBI to determine what is known about the structure of the protein, and embedded links provide easy access to the related scientific literature.
This experiment may require software and an interface for data collection.