Genome of Green Alga Unraveled

A research project, led by the U.S. Department of Energy Joint Genome Institute (DOE JGI); the University of California, Los Angeles; and the Carnegie Institution, and including contributions from over 100 international collaborators has uncovered hundreds of genes of a tiny green alga. Among the 15,000-plus genes revealed in the study are those that are uniquely associated with carbon dioxide capture and generation of biomass and also those that encode the structure and function of the specialized organelle that houses the photosynthetic apparatus, the chloroplast, which is responsible for converting light to chemical energy. The genome also provides a glimpse back through time to the last common ancestor of plants and animals. The research article is featured in the Oct. 12 edition of the journal Science.

The single-celled alga Chlamydomonas reinhardtii, while less than a thousandth of an inch in diameter, or about one fiftieth the size of a grain of salt, is packed with many ancient and informative surprises. Affectionately known to its large research community as "Chlamy", the alga is a powerful model system for the study of photosynthesis and cell motility. The genes that encode the alga's "flagella", which propel it much like a human sperm tail, were also cataloged in this study. Defects in these genes are associated with a growing list of human diseases.

"The Chlamy genome is like a green time capsule that affords a view into the complex core machinery that gave rise to today's energy-capturing and oxygen-producing chloroplasts," said Daniel Rokhsar, DOE JGI Computational Biology Program head, who co-led the effort with DOE JGI Computational Scientist Simon Prochnik, Arthur Grossman of the Carnegie Institution and Stanford University, and Sabeeha Merchant of UCLA.