Genome of lowly oyster has a lot to reveal

  • Wed Sep 19th, 2012 3:14pm
  • News

Bloomberg News Service

What’s it like to get half-asphyxiated twice a day, suffer through 90-degree swings in temperature, and be forced to eat everything that happens to come by your mouth?

Welcome to life as an oyster.

Starting today, biologists have a clearer window into what it takes for complex organisms to survive — and flourish — under such difficult circumstances.

An international team of 75 researchers on Wednesday published the full genome — the entire DNA message — of the Pacific oyster.

The toothsome Crassostrea gigas is the first mollusk whose genome has been fully sequenced. The information will shed light on the biology and evolution of one of the planet’s largest phylum of animals, with more than 100,000 species.

Analysis of the Pacific oyster’s genes will help biologists understand how mollusks form shells, a largely mysterious process that might eventually lead to production of artificial “bioceramics.” Its immune system genes may help identify the disease vulnerabilities of the world’s most commercially important oyster. The genes involved in reproduction may help explain how oysters begin their sexual lives as males and end them as females.

The most important insights, at least in terms of basic science, are likely to be on ways that oysters protect their cells from a wildly changing world they can’t escape.

“They have an exceptional ability to tolerate environmental stress,” said Ximing Guo, a professor of marine science at Rutgers University, co-leader of the four-year project.

An early look at the genome revealed that Pacific oysters have 48 genes coding for proteins that inhibit “programmed cell death”. The human genome has eight.

“That is something that is very surprising,” Guo said. “We thought they had a primitive system regulating this, one not as advanced as vertebrates.”

Programmed cell death, known technically as “apoptosis”, is a hot topic in biology, as it sheds light on both disease (in particular cancer) and aging.

The Pacific oyster genome has about 800 million pairs of DNA nucleotides, compared to 3 billion in the human genome. Oysters, however, have more genes than people _ 28,000 versus about 20,000.

The initial analysis of the oyster genome is published in the journal Nature.