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By Diana Kenney

The startling discovery of a contagious cancer in steamer clams, published this week in the journal Cell, had its origins at the MBL.

Carol Reinisch began studying a fatal, leukemia-like disease of soft-shell clams (Mya arenaria) at the MBL in the mid-1970s, when it was causing major die-offs among distinct bivalve populations. This week, scientists announced that the disease is a contagious form of cancer that has been transmitted between clam populations from New York to Prince Edward Island, Canada. The study was conducted by Michael Metzger and Stephen P. Goff of Columbia University, Jim Sherry of Environment Canada, and Reinisch.

The soft-shell "steamer" clam, Mya arenaria. Photo by Scott Bennett, MBL

The soft-shell “steamer” clam, Mya arenaria. Photo by Scott Bennett, MBL

Infectious cancer (or “super metastasis”) is known in only two other instances in nature: as a venereal disease in dogs and as a facial tumor in Tasmanian devils, according to an article about the clam leukemia in Science.

Reinisch, a few years ago, thought the clam disease might be caused by a virus, and she brought it to Goff’s attention. Metzger and Goff, she says, “conducted the truly elegant molecular biology to show the cancer is externally derived.”

Through genetic analysis of numerous sick clams, the team showed that while their cancer cells were nearly identical, the cancer cells did not match the genomes of their host clams. This indicates the cancer cells likely descended from a single, original clam cell “gone rogue,” which then multiplied and spread to nearby clams. How the disease was transmitted is still unknown.

Steamer clams are eaten by human beings and are an important commercial fishery. However, researchers say there is no health risk to humans who eat diseased clams. “Nobody eats them raw. When you steam or boil them, it kills all the cells,” Reinisch says.

Reinisch has studied this clam and bivalve disease for decades because “it’s one of the best and unique models of carcinogenesis in nature that we have,” she says. She carried out research at MBL for more than 30 years, first as a Whitman summer investigator and then, from 1998 to 2005, as a year-round scientist. She moved her lab to the MBL in order to explore Mya arenaria as a model system for cancer. Formerly, she was a Department Chair of Comparative Medicine at Tufts Veterinary School.

Reinisch’s earlier work indicated that the spread of the clam leukemia has an environmental component. “For whatever reason, the [cancer] transmission seems to be easier in stressed areas,” she says. “When we used to collect clams in New Bedford, Mass., we knew exactly where to find the ones with leukemia. The clams in a PCB contaminated site were much more liable to have the disease.”

Currently, Reinisch collaborates with Environment Canada in Burlington, Ontario, and is identifying the range of this transmissible cancer. She has studied bivalves as far north as Alaska and the Arctic and hopes to conduct field research in Antarctica in the coming year.


Metzger, MJ, Reinisch C, Sherry J, and Goff SP (2015) Horizontal transmission of clonal cancer cells causes leukemia in soft-shell clams. Cell 161: 255-263.


Bill Klimm, captain of the Gemma, the MBL's collecting vessel. Credit: Daniel Cojanu

Bill Klimm, captain of the Gemma, the MBL’s collecting vessel. Credit: Daniel Cojanu

When Nature began pursuing a story on “unsung heroes” in science — the behind-the-scenes staff who make the whole operation happen — it became clear that plenty of people at the MBL fit that bill. One is Bill Klimm, captain of the Gemma, who as a longtime fisherman knows not only how to operate the boat, but where to find the elusive fish and other marine organisms used for MBL research. Nature published a wonderful profile of Klimm this week, including the video below. Thanks to Bill, Dave Remsen, Dan Sullivan, and everyone who works hard every day to make the MBL’s collecting operation succeed!


By Laurel Hamers

Our arms and legs normally work so fluidly that we may forget that their size and location were determined by complex genetic control during early development.

Keys to the precise regulatory ballet that makes our limbs look the way they do may be found in a seemingly dissimilar group of organisms: sharks and skates.


Skates in the MBL’s Marine Resources Center. Photo credit: Laurel Hamers

Cartilaginous fish like sharks and skates are the oldest fish to have pectoral fins:  paired appendages that are the evolutionary predecessor of our arms. Tetsuya Nakamura, a postdoctoral researcher at the University of Chicago, is spending the summer at the MBL investigating these cartilaginous fish. He hopes to elucidate the molecular mechanisms responsible for the diversity of fin shapes in this single group of fish and, on a broader scale, the evolution of appendage shapes across species.

“The best way to understand the diversity of fin types is to study an extremely strange fish, like the skate,” says Nakamura. “The pectoral fins of skate are very wide—they’re totally different from other animals.”

Nakamura is focusing on Hox genes, which control body patterning during embryonic development; they are responsible, for example, for making sure your arms attach below your shoulders and not out the top of your head. Researchers can manipulate individual Hox genes and readily see structural differences in the body parts influenced by that gene.

By comparing expression patterns of Hox genes in the fins of skates and closely related sharks, Nakamura is identifying specific genes that may be responsible for the skate’s elongated pectoral fins compared to the shark’s narrower ones. He will then manipulate the expression of these genes in an attempt to alter fin shape.

The blue lines show the cartilage structure in the fins of two fish. Note the shark's narrow fins compared to the skate's wide, fan-like ones. Photo credit: Tetsuya Nakamura, composite image by Laurel Hamers

The blue lines show the cartilage structure in the fins of two fish. Note the shark’s narrow fins compared to the skate’s wide, fan-like ones. Photo credit: Tetsuya Nakamura, composite image by Laurel Hamers

“My opinion is that fin width is very important in deciding fin shape,” he says. “If I can control fin width, for example, to make narrower fin bases in skate, I think their fin shape would be like a shark’s.”

Nakamura, who is spending his first summer at MBL, is a member of Neil Shubin’s lab in the Department of Organismal Biology and Anatomy at UChicago.

A whimsical, enlightening video about cuttlefish camouflage by Jacob Gindi, a senior and biology major at Brown University, appeared in The New York Times last week. Gindi had encountered live cuttlefish when he visited the MBL’s Marine Resources Center as a student in The Art and Science of Visual Perception, a Brown course co-taught by Roger Hanlon of the MBL and Mark Milloff of Rhode Island School of Design. Gindi then had a chance to make a CreatureCast video in Casey Dunn’s Invertebrate Zoology class at Brown. Inspired by Hanlon’s research, Gindi’s artful video about the cuttlefish’s amazingly adaptive skin can be enjoyed by marine biology-lovers of all ages.

“It is so gratifying to see science and art promoted at this national/international scale,” says Hanlon, an MBL senior scientist and professor in Brown’s Ecology and Evolutionary Biology Department through the Brown-MBL Partnership and Graduate Program.

CreatureCast, a collaborative blog produced by members of the Dunn Lab, is supported by a National Science Foundation grant.