What is the cytochrome c gene, and why would that gene be useful for constructing a phylogenetic tree?

The cytochrome c gene that encode the hemi-protein in the internal-wall of the mitochondria useful in the electron transport chain through the transfer of electrons. This difference in the amino acids produced from this gene are used to identify the accumulated mutation that had occured in an organism, therefore, similarity will suggest common origin.

Explanation:

The cytochrome c gene is represented as: CYCS gene. This gene encode the complex of cytochrome found in the internal walls of the mitochondria, an heme-protein that is useful during the electron transport system in the mitochondria by transferring electrons to the oxidase complex. Since this gene does not undergo mutation and modification easily as others found in the soma cells, it holds the evolutionary trend within each organism. This is useful therefore, for comparing two or more organisms to each other to identify their similarity, and use this similarity in the amino acid translated from the genetic sequence in this cytochrome c gene to predict the origin of each organism and identify the mutation that had occured in the past, and thereafter come up with the phylogenetic tree.