Determining Relatedness using Gel Electrophoresis to Compare Muscle Protein Composition

Aaron Oberstadt
Team ZAME
2/9/2017
Prof Jenny McFarland

In our group research project, we are attempting to determine the relatedness of different aquatic species using protein gel electrophoresis to identify the major components of their muscle protein compositions. These species include mussel, oyster, scallop, squid, and octopus, with shrimp as an outgroup.

The evolution of muscles is unique to animals in the tree of life. Though signs of muscular origins exist before cnidarians, true muscle tissue emerged with the formation of mesoderm in triploblasts. Muscle tissue has evolved over time and is highly diverse in form and function; three main types exist (smooth, obliquely striated, and transversely striated), each with different levels of thin and thick filaments. Each arrangement of muscles has some level of specialization, and with each muscle arrangement, differing types, quantities, and sizes of proteins exist.

An example of this is shown in bivalved animals, such as mussels and scallops. These have adductor muscles which close their valves (e.g. mantle). This specialized function has a specialized form: they contain "Transversely striated muscles with discontinuous Z lines consisting of multiple small electrondense patches" (Paniagua 1996). It is clear, however, that these are not all the same species! Despite similar form and/or function, each animal is different and is therefore likely to have slight variations in overall protein composition. We ultimately hope to determine whether protein comparison in similar muscles between organisms can be an accurate measure of relatedness.

References

Paniagua R, Royuela M, García-Anchuelo RM, Fraile B. Ultrastructure of
invertebrate muscle cell types. Histol Histopathol. 1996 Jan;11(1):181-201.
Review. PubMed PMID: 8720463.