Pacific oyster - Crassostrea gigas - farming. (Photo: Luis Eustaquio)
Genome reveals oysters’ adapatability to stress
Friday, September 21, 2012, 03:00 (GMT + 9)
On analyzing the genome of the Pacific oyster (Crassostrea gigas), researchers from the Institute of Oceanology of the Chinese Academy of Sciences discovered that its genetic information is tailored to the risk factors of its habitat, which is really changeable.
Besides, they found that the formation of the shell is more complicated than previously thought.
According to Guofan Zhang, a scientist at the Institute and the research leader, "molluscs have developed a large number of gene families able to adapt to stress."
Zhang is one of the initiators of the Oyster Genome Project in China, one of the major producers of aquaculture oyster, reported SINC.
The team of experts found that the genes of the Japanese oyster respond when the body is subjected to risk agents, such as changes in temperature, in salinity, exposure to air and heavy metals.
The Pacific oyster is polymorphic, like other marine invertebrates, that is to say, it contains multiple alleles for the same gene.
To overcome this obstacle, the researchers sequenced, assembled and analyzed the variable genome of the oyster using a collection of short DNA sequences, called fosmids, with fosmid-pooling strategy, "which is useful in cases of polymorphism such as the genome of this mollusc," explained Zhang.
The team also sequenced 61 transcriptomes -- parts of the genome that are expressed in the cell under certain circumstances – of nine oysters exposed to nine environmental risk factors.
Of the genes that this oyster has, 5,844 were expressed differently given at least one of those factors. The researchers determined that what causes them more stress is the exposure to air, the study published in the journal Nature points out.
The group of scientists who participated in the study identified 259 proteins in the shell of the oyster.
By Analia Murias