Phylogenetic Analysis by Molecular Similarity

 

Tested Studies in Laboratory Teaching, 2018, Volume 39

Robert J. Kosinski

Abstract

This exercise is used in the introductory biology course for majors at Clemson University. Students first learn how to interpret a phylogram. Then they download a series of protein sequences from a Web site. Each series contains the sequence for a human protein plus some other homologous sequences in organisms progressively less related to humans. There are 17 proteins used, so every pair of students even in a large lab section can use a different one. The students input their sequences into Phylogeny.fr, which produces a phylogram showing their relative similarity. The students use this to test the hypothesis that similarity of homologous protein sequences increases with taxonomic relatedness. Some proteins show the expected relationship, some show it with a few exceptions, and a few highly-conserved proteins like dynein deviate seriously.

Keywords:  protein, phylogeny, molecular phylogenetics, phylogram, Phylogeny.fr

University of Wisconsin, Madison (2017)