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5 December 2013 11:26 am ,
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An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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30 September 2004 (All day)
Diatoms are an enigma. Neither plant nor animal, they share biochemical features of both. Though simple single-celled algae, they are covered with elegant casings sculpted from silica. Now researchers have sequenced the genome of a frequently studied diatom species, taking a big step toward resolving the paradoxical nature of these odd microbes.
Diatoms occupy vast swaths of ocean and fresh water, where they play a key role in the global carbon cycle. They're a source of food for many organisms, as well as the cause of ocean "blooms" that are sometimes toxic. "This is a group of organisms that has amazing importance in global ecology," says Deborah Robertson, an algal physiologist at Clark University in Worcester, Massachusetts.
Since 2002, Daniel Rokhsar, a genomicist at the DOE Joint Genome Institute in Walnut Creek, California, and his colleagues have been unraveling the genome of the saltwater diatom Thalassiosira pseudonana. The draft genome consists of 34 million bases and about 11,500 genes, Rokhsar and 44 colleagues report in the 1 October issue of Science.
Analyses of these genes and the proteins they encode confirm that diatoms have had a complex history. Like other early microbes, they apparently acquired new genes by engulfing microbial neighbors. Perhaps the most significant acquisition was an algal cell, which provided the diatom with photosynthetic machinery. Some biologists hypothesize that diatom ancestors branched off from an ancestral nucleated microbe from which plants and animals later arose. As diatoms, plants, and animals evolved, each must have shed different genes from this common ancestor. As a result, diatoms were left with what looks like a mix of plant and animal DNA.
The newly analyzed genome has also begun to shed light on how a diatom constructs its intricately patterned glass shell. So far, Rokhsar and his colleagues have uncovered a dozen proteins involved in the deposition of the silica and expect to find more. Such progress could be a boon to materials scientists, says Robertson. With the genome in hand, interest in diatoms is going to expand, predicts Edward Theriot, a diatom systematist at the University of Texas, Austin: "It will help put diatoms on everyone's radar."