Why Sequence the California Mussel?

Sequencing the mussel Mytilus californianus will have direct impacts on multiple DOE missions. The fields of ecotoxicology and environmental remediation stand to benefit from their ability to sequester toxins. Mussels are frequently used as sentinel organisms for monitoring the accumulation of pollutants in marine ecosystems. The measurement of chemicals in mussel tissue provides an estimate of the biological availability of a contaminant. Besides acting as sentinel organisms, Mytilus populations can be seeded to act as biological clean-up agents for biotransformation of contaminated sites. Identifying the genes that allow mussels to accumulate and sequester, as well as tolerate, environmental contaminants may identify novel enzymes that could be targets for manipulation in biotechnology.

This project could also pay dividends in human health, since bivalves are an important human food source and can occasionally contain infectious agents or toxins. Because bivalves have evolved mechanisms to store toxins, toxin levels must normally be assessed through bioassays that test bivalve extracts for their effects on cells and animals in the laboratory. An annotated Mytilus gene array could be used to more easily identify genes whose expression is linked to toxin exposure and thus provide biomarkers of exposure to those toxins.

A Mytilus sequence will also be of use in studies related to climate change. Mytilus frequently inhabit the high intertidal areas of the shore and are subject to the prevailing climatic conditions when exposed to air at low tide. Thus, global climate change is predicted to affect the local distribution of Mytilus. The identification of molecular markers of extreme stress and measurement of their incidence in natural populations will help quantify the effects of global climate change on the distribution and composition of intertidal communities. Mytilus sequence data could also have applications in carbon sequestration, since shellfish such as Mytilus sequester CO₂ as calcium carbonate during shell deposition. Mytilus could be cultured inexpensively at high density to reduce the greenhouse gases released by burning fossil fuels.

CSP project participants: Andrew Y. Gracey (proposer) and George N. Somero (Stanford Univ.).