Algae genome could aid medical, climate research


Cal State San Marcos researchers unlocked the genome for a type of algae found around the globe, a finding they said has potential applications to fields ranging from climate change to dentistry. The study sequenced 13 strains of the phytoplankton Emiliania huxleyi, to document the first algal “pan-genome:” a set of genes shared by diverse algal varieties. While the different strains share 70 to 80 percent of their DNA, about 20 to 30 percent of their genes are unique to each strain, allowing them to inhabit virtually all the world’s oceans except the polar seas.

“They have this tremendous ability to adapt,” said lead author Betsy Read, a professor of molecular cell biology at CSUSM. “This is why we can pull them from almost every bucket of water in the ocean.”

Read released the findings in the journal Nature last week, in collaboration with computer science professor Xiaoyu Zhang and the late microbiologist Tom Wahlund, both from CSUSM, and Igor Grigoriev from the U.S. Department of Energy’s Joint Genome Institute. As Read sequenced the genome, Zhang wrote the bioinformatics programs to analyze them.

The algae are the third most abundant phytoplankton, and are a key component of the ocean food chain, nourishing animals including crustaceans, shellfish and other filter feeders.

They’re characterized by their intricate shells, composed of interwoven lattices of calcium carbonate.

“We kind of think of them as flowers of the ocean,” Read said.

Those shells reflect light, tinting the ocean surface a milky turquoise shade which can be seen in satellite images during massive algal blooms. The White Cliffs of Dover owe their pale hue to fossilized remains of the algae.

“They’re arguably the most important species you can see from outer space, because of the light reflecting properties of its shell,” Read said.

The creatures absorb calcium dioxide to build their shells, playing a potentially significant role in the global carbon cycle.

“It fixes carbon for energy and its shell, but also releases carbon,” Read said, noting that scientists are examining the balance between its carbon use and carbon emissions.

That could reveal ways to capture excess carbon dioxide from the atmosphere. In addition, the organic sulfur compounds Emiliania huxleyi releases is known to seed clouds and could influence weather, she said.

The algae’s calcification process could also pave the way for new biomedical devices, such as joint replacements or dental implants, Read said. And it could illuminate the healthy calcification that occurs during bone growth, and the unhealthy calcium deposits that occur in conditions such as kidney stones and heart disease.

“Knowing the genes and proteins opens up more waves of research to answer these questions,” Read said.

Source: UT SanDiego