The similarities in red, green algae

February 15, 2011
The similarities in red, green algae
Red algae, Calliarthron tuberculosum.

( -- For Debashish Bhattacharya, the knowledge that half the oxygen on Earth is generated by algae through photosynthesis begs an important evolutionary question: How did algae come to be such ndustrious carbon-dioxide-consuming, sugar-and-oxygen producing factories? Did each of the two major kinds of algae, red and green, evolve their photosynthetic abilities separately? Or did they have a common ancestor?

Red algae are mostly aquatic and include such familiar organisms as sushi wrap and are the sources of agar and carrageenan. are terrestrial, and are genetically related to all land plants.

Thanks to the recent research of Bhattacharya and his co-authors, published in the journal Current Biology, it appears likely that red and green algae do have a , since they share about half the genes in their their genomes. Scientists had long thought this must be so, but had little evidence to back up their hunch, because genomes are usually very large, and their sequencing was such a long, involved, expensive process.

In fact, scientists since Darwin’s time have hoped to construct a great genealogy, or “tree of life,” which could describe the interrelationships of all living things on the planet. Bhattacharya and his co-authors undertook to unite a key limb of that “tree,” the limb that includes all red algae, green algae and land plants.

“What we knew about red algae we learned from sequencing extemophiles – algae that live in extreme environments – because their genomes are relatively small,” said Bhattacharya a professor of ecology, evolution, and natural resources in Rutgers’ School of Environmental and Biological Sciences. “But most red algae are mesophiles, which means they live in relatively normal temperatures.”

But recently, a new generation of gene sequencing machines has become available, and Bhattacharya’s lab has acquired one. This machine allowed him and his co-authors to sequence the entire genome of Calliarthron tuberculosum and a comprehensive list of expressed genes - genes caught in the act of fulfilling their functions - for Porphyridium cruentum, two species of red algae, in just a couple of weeks. They were then able to compare this bonanza of data to all the data available in protein banks, discovering that red and green algae shared half their genomes – and that red algae also shared a considerable part of its genome with other, non-algae organisms.

“The availability of next-generation sequencers has opened the window to generate sequences from all kinds of organisms,” Bhattacharya said. “This has opened our eyes to how complicated the history of genes is in the tree of life. Here, we finally got genomic data for normal red algae, and that’s opened our eyes to, holy smoke, how complicated they are.”

Bhattacharya believes the research has important practical implications. “The ancestor gave rise to the algae that generated all the fuel we currently use in cars and planes, and the photosynthetic organelle they contain is the target for modern biofuel research using fast-growing algae.”

Knowing what red and green algae will help scientists to figure out how they differ, and how those differences may be manipulated to create better algae for biofuel research, according to Bhattacharya. “For example, these algae could be designed to incorporate desirable characteristics from both lineages,” he said.

Explore further: Deep-sea algae may be 'living fossils'

Related Stories

Deep-sea algae may be 'living fossils'

November 19, 2010

( -- Researchers in the US and Belgium say two types of deep-sea seaweed may be representatives of ancient forms of algae previously unrecognized.

Britain cites important algae locations

January 30, 2008

Fifteen locations in the United Kingdom are being labeled internationally important because they contain rare and diverse forms of algae.

Noxious algae gone, but who knows how long

January 3, 2007

Recent storms may have washed away algae blooms in a Florida chain of lakes, but experts said algae threats remain because of pollution feeding the lakes.

Green energy from algae

June 25, 2010

( -- Visitors to this year’s UK Royal Society Summer Exhibition will have a chance to discover how scientists from the University of Cambridge are studying ways to harness algae as a renewable energy source.

Recommended for you

The astonishing efficiency of life

November 17, 2017

All life on earth performs computations – and all computations require energy. From single-celled amoeba to multicellular organisms like humans, one of the most basic biological computations common across life is translation: ...

Unexpected finding solves 40-year old cytoskeleton mystery

November 17, 2017

Scientists have been searching for it for decades: the enzyme that cuts the amino acid tyrosine off an important part of the cell's skeleton. Researchers of the Netherlands Cancer Institute have now identified this mystery ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.