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Imagine a creature that can grow its own spear and helmet when threatened by an attacker. There is one and the federal government was intrigued enough to fund a major effort to investigate this fierce little creature's genetics. NPR's Joe Palca reports.
JOE PALCA: Anything that can grow its own armor sounds pretty scary. But it's hard to be afraid of a creature named Daphnia.
JOHN COLBOURNE: Daphnia are small crustacea, about the size of an equal sign on your keyboard.
PALCA: Other crustaceans you might be familiar with are shrimps and lobsters. Daphnia are a bit different.
COLBOURNE: They are transparent.
PALCA: Well, so are a lot of us. But in Daphnia's case it's literally true you can see right through them. That transparency also led the first scientists who saw Daphnia to think it was a flea.
COLBOURNE: When they first noticed this organism, sometimes they would be found to be bright red.
PALCA: So, scientists thought they were bloodsuckers and called them water fleas. Turns out, they're not bloodsuckers, they're blood makers. Daphnia have genes that make hemoglobin. So, when the animal is stressed out, these genes switch on and Daphnia looks red. In fact, Daphnia have an astonishingly large number of genes.
COLBOURNE: The genome measures only 200 million bases and yet within this region we count over 31,000 genes.
PALCA: For comparison, the human genome has more like 23,000 genes. If Guinness tracks such things, Daphnia would hold the record for the most genes of any animal studied to date. And Colbourne says Daphnia has another surprise.
COLBOURNE: Many of those genes - we estimate around 35 percent of them - are brand new to science.
PALCA: Now, if you're like me, you might be wondering something: Why does a simple organism like Daphnia need more genes than a human being?
COLBOURNE: It's hard to say need more genes, because that would mean evolution has a goal. In this case it's obviously found some way to use more genes.
PALCA: Jeff Dudycha of the University of South Carolina says knowing the DNA sequence of Daphnia is particularly useful because many of the animals used for genetic research have only been studied in the lab.
JEFF DUDYCHA: It's virtually impossible to figure out much about their ecology in nature.
PALCA: Saran Twombly is a program officer at the National Science Foundation, one of the federal agencies that supported the investigation of Daphnia's genetics. She agrees that Daphnia provides some unique research opportunities.
SARAN TWOMBLY: What is it about the genome that allows an organism to be so flexible in response to its environment?
PALCA: Twombly says you shouldn't be surprised that it's possible to learn something fundamentally important about life on Earth from a critter about the size of a grain of rice.
TWOMBLY: Most of what we know about biology comes from decidedly uncharismatic organisms: worms, flies, bugs. We can grow them easily, we know what to feed them, we can do experiments with them. Can't do any of that stuff with lions and tigers and bears.
PALCA: Joe Palca, NPR News, Washington.
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