Sponge Genome Goes Deep

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atomic force microscopy. g . go.nature.com/MS8XAP l crop’s drug will be produced. This year, the Assured Artemisinin sponge genome goes deep Supply System (A2S2) initiative, supported by the international drug-purchasing facil- ity UNITAID, began to give advance loans With a simple body plan lacking organs, window, some 150 to 200 million years in to the companies that extract artemisinin muscles and nerve cells, the sea sponge duration, when the basics of multicellular from plants, and to encourage drug firms to hardly seems a rich avenue for study. Yet life emerged. Nearly one-third of the genetic sign long-term contracts with them. About this humble organism squats firmly at the alterations that distinguish humans from 10,000 hectares of Artemisia was planted this doorway to one of life’s great mysteries: the their last common ancestor with single- year, twice as much as in 2009. But recent leap to multicellularity. celled organisms took place during this floods in China and Vietnam, and a drought Telltale molecular fragments teased out of period. These changes would have occurred in East Africa, mean that yields of artemisi- ancient sediment1 show that sponges existed within our sponge-like forebears. nin for use in 2011 may be only two-thirds of some 635 million years ago — the oldest The researchers also identified parts what has been planted, says Cutler. evidence for metazoans (multicellular of the genome devoted to suppressing animals) on Earth. Now, a draft genome individual cells that multiply at the expense Breeding boost sequence of the Great Barrier Reef of the collective. The presence of such Yields could be vastly improved by planting demosponge (Amphimedon queenslandica), genes indicates that the battle to stop rogue new Artemisia strains. On average, one kilo- published in this issue2 (see page 720), cells — in other words, cancer — is as old gram of its dried leaves yields some 8 grams offers a comprehensive look at the genetic as multicellularity itself. Such a link was of artemisinin. But at the National Institute mechanisms that first allowed individual recently hinted at by work showing that of Agricultural Botany in Cambridge, UK, cells to work together as parts of a larger certain ‘founder genes’ that are associated researchers have used selective breeding whole. As an added benefit, this genome to create hybrid plants that produce up may shed light on how primitive animal

to 24 grams, says Colin Hill, chair of an cells first learned to cope with the enduring authier g

Artemisia breeding consortium supported hazard of collective existence: cancer. M. by the UK Department for the Environ- “As the earliest branching lineage from ment, Food and Rural Affairs. These our last common ancestor, sponges can tell plants are now being grown and harvested us a lot about what is needed to make an commercially in Madagascar, and trialled in animal,” says geneticist Mansi Srivastava, South Africa, Uganda, Zimbabwe and the the paper’s lead author, now a postdoc at the United States, as well as in Britain. Massachusetts Institute of Technology in In an alternative approach, Ian Graham Cambridge. and colleagues at the University of York, UK, With more than 18,000 individual genes, The genome of the demosponge A. queenslandica identified key Artemisia genes that could the sponge genome represents a diverse offers a glimpse at the dawn of multicellular life. optimize agricultural yields, robustness or toolkit, coding for many processes that other desirable traits when the plant is grown lay the foundations for more complex with human cancers first arose at about in different areas of the globe (I. A. Graham creatures. These include mechanisms for the same time as metazoans appeared3. et al. Science 327, 328–331; 2010). Graham telling cells how to adhere to one another, The demosponge genome shows that genes says that the work has helped to create plants grow in an organized fashion and recognize for cell suicide — those activated within that produce up to 50% more artemisinin per interlopers. The genome also includes an individual cell when something goes kilogram of leaves than the best commer- analogues of genes that, in organisms with wrong — evolved before pathways that are cial variety. They expect to release seed to a neuromuscular system, code for muscle activated by adjacent cells to dispatch a commercial growers in mid-2012. tissue and neurons. cancerous neighbour. Despite the advances in plant bio- According to Douglas Erwin, a “Cell suicide predated cell homicide,” says technology, Keasling says that semi-synthetic palaeobiologist at the Smithsonian Carlo Maley, an oncologist at the Wistar artemisinin is still sorely needed. Although Institution in Washington DC, such Institute in Philadelphia, Pennsylvania. it began as a way to make the drug more complexity indicates that sponges must have This suggests that the single-celled colonial cheaply, the mass-produced semi-synthetic descended from a more advanced ancestor organisms that gave rise to our ancestors will be no cheaper than the plant-derived than previously suspected. “This flies in had already evolved mechanisms to kill version — partly because Sanofi-aventis does the face of what we think of early metazoan themselves, which multicellular creatures not want to undercut farmers. Instead, it will evolution,” says Erwin. later exploited as a cancer defence. be used to smooth out the cycle of boom and Charles Marshall, director of the “Cancer was not the original motivation bust in crop-based artemisinin supply. “A University of California Museum of for this work,” says Srivastava. “But now stable and adequate source of artemisinin Paleontology in Berkeley, agrees. “It means we can learn about the ways in which would be fundamentally important,” says there was an elaborate machinery in place multicellular animals have to regulate Silvia Schwarte of the World Health Organi- that already had some function,” he says. themselves and the original function of zation’s malaria programme. “What I want to know now is what were these genes.” ■ As Newman says: “If you suddenly need all these genes doing prior to the advent of adam Mann twice as much artemisinin, you just fire up sponge.” 1. love, g. D. et al. Nature 457, 718–721 (2009). ■ another fermenter.” The analyses of Srivastava and her 2. srivastava, M. et al. Nature 466, 720–726 (2010). Richard Van Noorden colleagues suggest that there was a crucial 3. Domazet-lošo, t. & tautz, D. BMC Biol. 8, 66 (2010).