Using Cytochrome-C to Explore Evolutionary Relationships


Daniel Rouillard

The High School for Arts, Imagination, and Inquiry

New York, New York


Summer Research Program for Science Teachers

August 2007


Course:  Living Environment/Biology


Grade Level:  9th Grade


Unit:  Evolution



         Assess how genetics provides evidence for evolution

         Compare molecular evidence to generate conclusions on evolutionary relationships

         Create graphic representations of the relationships between the different species (Cladograms)

         Analyze proteins sequences using BLAST and Biology Workbench



Introduction: In this lab activity students will make use of molecular evidence to research the evolutionary relationships of different organisms.  This lesson uses two different internet tools.  The first of which is BLAST to obtain cytochrome-c protein sequences for 10 different organisms.  The other is Biology Workbench which contains numerous tools for multiple alignment analysis.  This will allow students to look up and analyze protein sequences and make conclusions on their evolutionary relationships.  After completion of this activity students will be able answer questions on the relationships between humans and other organisms.  This data along with various articles will supply data for a paper where the students will defend the idea that humans have evolved from other organisms. 



Time Required: 2 – 45 minute periods or 1 Block period

Teacher Procedure:


1.  Using a computer with and LCD projector go to the NCBI website, and introduce what this site and its resources are for.  After a brief explanation, go through the same steps that the students will (below).  As you go through accessing a protein sequence it is a good time to review protein synthesis and for the students to realize they are looking at amino acids which are made by the DNA code.


2.  After you give students a briefing, hand out Student Handout #1 to each set of lab partners.  Inform them that they will be working together to retrieve amino acid sequences for cytochrome-c from a number of organisms.   The student handout will walk them through using BLAST and BioWorkbench. 


3.  Inform students that after they analyze their sequences on BioWorkbench they will be completing the “Evolutionary Relationships and Cladogram Handout”. 


4.  If students finish early (which some will as some are more computer savvy than others), have them work on the Post-Lab extension. 


5.  Close out the lab by discussing the following ideas.

What are some ideas that you have learned in this lesson?

Is there anything here that surprises you?

            What does this evidence suggest about humans?

            What are, according to this data, some of our most closely related ancestors?



Post-Lab Extension:


1.   Use this evidence and other evidence found at the

            provided websites to write an argument supporting

            the idea of human evolution from other organisms. 

            Use specific examples from today's data and from

            the websites provided to back up your argument.

            Also include and graphic organizers (such as your

            rooted tree and evolutionary relationship matrix, to

            support your claim.  If you have time look up other

            of information online to help support your claim.



NYS Math, Science, and Technology Learning Standards:


National Science Learning Standards:

§  Content Standard A: As a result of activities in grades 9-12, all students should develop abilities to do scientific inquiry and an understanding about scientific inquiry

§  Content Standard E: As a result of activities in grades 9-12, all students should develop abilities of technological design and understandings about science and technology

§  Content Standard F: As a result of activities in grades 9-12, all students should develop understanding of science and technology in local, national, and global challenges

§  Content Standard G:  As a result of activities in grades 9-12, all students should develop understanding of the nature of scientific knowledge