Archive of Spotlight Feature Articles

Crustacean Gets Designer Genes

University of Connecticut
Sea Grant College Program

Crayfish with transplanted gene

The first crustacean (crayfish) to have genes transplanted from another species (a bacterium). (Photo from UConn laboratory)

Eggs with foreign gene

Eggs bearing the foreign gene, borne by the female crayfish. (Photo from UConn laboratory)

In a Sea Grant project at the University of Connecticut, Dr. Tom Chen, Director of the University of Connecticut Biotechnology Center, has transplanted a foreign gene into a crustacean, for the first time in history! The gene Chen inserted was a "reporter" gene - a gene that is easy to detect and confirm in the animal's cells - to prove that the procedure has been successful. Now that the technique has been demonstrated, it's only the beginning of the exciting possibilities. The technique could be applied some day to shrimp and other crustaceans such as crabs and lobster to improve characteristics like color, taste, growth rate, size, and disease resistance, for aquaculture. While feeding animals hormones can accomplish the goals of faster growth and enhanced reproduction, a growth hormone gene successfully transferred to an animal allows the animal itself to produce the hormone, and the trait may be carried on to its offspring.

... a growth hormone gene successfully transferred to an animal allows the animal itself to produce the hormone, and the trait may be carried on to its offspring.

Chen explains that transplanting genes in crustaceans is difficult because it requires access to unfertilized eggs, and the eggs laid by wild females are usually fertilized by the time they are collected.

"We are now one step ahead in our adventure," says Chen. "We are able to insert the gene directly into the immature gonads." Using a small, sharp knife, Chen makes a small hole in the exoskeleton of an immature crayfish near its thorax, where the testes and ovaries are located. Then he delivers a new gene, in the form of a "pantropic retroviral vector" - a small segment of the desired DNA encased in the shell of a virus. The new gene then appears in the eggs or sperm and is perpetuated in subsequent generations. Chen's past efforts have included transferring genes in finfish and mollusks. For example, he introduced growth-enhancing hormones into young scallops, hypothesizing that faster-growing scallops might better survive winters in Long Island Sound and reach market size sooner. In an earlier project sponsored by Maryland Sea Grant, Chen and Yonathan Zohar, Director of the Center for Marine Biotechnology at the University of Maryland, cloned genes for a hormone that regulates reproduction in striped bass.

You can contact Dr. Tom Chen at tchen@uconnvm.uconn.edu

The Connecticut Sea Grant College Program, based at the University of Connecticut at Avery Point, funds marine research and is a primary source of information about marine and coastal issues, including those related to Long Island Sound. Current research areas include aquaculture, crustacean growth and reproduction, environmental concerns of Long Island Sound, marine biotechnology, seaweed cultivation, salt marsh sediment accretion, sea level rise, introduced species, zebra mussel prevention and identification, watersheds and water quality, and harmful algal blooms. For more information visit the program's website at: http://www.ucc.uconn.edu/~wwwsgo/, or write to:

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