March 1, 2007 Researchers are using the sea urchins to study and understand diseases like cancer, Alzheimer's disease, Parkinson's disease and muscular dystrophy. Although they are invertebrates, the creatures share a common ancestor with humans and have more than 7,000 of the same genes. With a complete map of their DNA, scientists can learn how to treat and prevent diseases in humans better.
They're small, spiky and spineless. But what do prehistoric sea urchins have in common with humans? Uncovering their mysteries may help solve some of science's most difficult and deadly problems.
"At a genetic level, ah, they're actually related to us. So sea urchins and humans share a common ancestor," Cristina Calestani, a developmental geneticist at University of Central Florida in Orlando, tells DBIS.
...Even though they don't look like us.
Sea urchins and humans share more than 7,000 genes, and biologists are now using these sea creatures to unlock the mysteries of human diseases. In fact, there are several genes in the sea urchin involving Alzheimer's, Parkinson's disease, muscular dystrophy and many other cancer-related genes. And infertility may be another problem the sea urchin helps solve. No wonder -- each urchin can produce 20 million eggs.
When you compare the human and sea urchin genes, quite a few of the amino acid sequences are a perfect match.
"You really need a relatively simple system in order to study ... but still, also you want it to be complex enough and closer enough to vertebrate in order to use this information," Calestani says.
Sea urchins are one of the few invertebrates on our branch of the evolutionary tree, sharing more genes with humans than fruit flies and worms -- and can be reproduced for research faster than other animals. Calestani says that means researchers can produce large amount, practically unlimited amount of material. And with a complete map of the urchin's DNA, they can better understand how genes work, so when diseases like cancer strike, maybe someday doctors will know exactly how to treat and even prevent them.
Another fascinating fact is sea urchins don't have eyes, ears or a nose, but they have the genes humans have for vision, hearing and smelling.
BACKGROUND: Sea urchins might not seem to have much in common with human beings, since they are small and spiny, have no eyes, and eat only kelp and algae. But scientists with the Sea Urchin Genome Sequencing Project, funded by the National Institutes of Health, recently completed sequencing of the genome. They found that the sea urchin genome is very similar to that of humans, and may hold the key to preventing and curing several human diseases.
ABOUT SEA URCHINS: Sea urchins are echinoderms, marine animals that originated more than 540 million years ago. Sea urchin "roe" (actually the gonads that produce the creature's roe) are popular in Korean and Japanese cuisine, and is also a traditional food in Chile. Beyond their culinary attractions, sea urchins are known for strong immune systems and long life spans; some can live up to 100 years The project scientists are especially interested in how the sea urchin's immune system works. Humans are born with innate immunity and also acquire additional immunities over time, as the body produces antibodies in response to infections. Sea urchins only have innate immunity, with 10 to 20 times as many such genes than humans. The hope is that studying sea urchins will provide a new set of antibiotic and antiviral compounds to fight various infectious diseases.
WHAT IS A GENOME? A genome is all of the DNA found in an organism, including its genes and DNA that does not contribute to genes. Every animal and plant has its own unique genome. Genetic DNA carries information for making the proteins required to sustain a living organism. The genome of the purple sea urchin is comprised of 814 million "letters" that code for 23,300 genes. Of those, it has 7,000 genes in common with humans, including genes associated with Parkinson's, Alzheimer's, and Huntington's diseases, as well as muscular dystrophy. Despite having no eyes, nose, or ears, the creature has genes involved in vision, hearing and smell in humans.
Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.