Toxin Resistance in Clams

Soft shell clams (Mya arenaria) are bivalves native to the east coast of North America.  They have become invasive species elsewhere throughout the northern hemisphere, inhabiting brackish waters, estuaries and marine environments.

Soft shell clams are susceptible to toxins that are associated with certain algal bloom events. These events are characterized by an upwelling of dinoflagellates, microscopic algal protists that naturally produce toxins harmful to marine organisms. Clams that are not resistant to the toxin often die. However, toxin resistance can occur if there is a mutation in the clam’s voltage gated sodium channel gene.

This case will examine the evolution of toxin resistance in clams.