A new study shows that a contagious blood cancer jumped from one species of clam to another. It is spreading among clams living in the Atlantic Ocean and Mediterranean Sea. The study published in eLife.
The finding add evidence that cancer is spreading among different species of bivalve shellfish. Scientists suggested that human activities are contributing to the spread of these cancers to new locations and species.
Contagious cancer is identified in dogs, Tasmanian devils, clams and mussels. This disease spread among individuals of the same species. Previous studies have documented two cases of contagious cancers spreading among clams and mussels.
The scientists collected 345 warty venus clams from the coastal areas of Spain, Portugal, France and Ireland. Scientists found a type of blood cancer named hemic neoplasia in warty venus clams. These were collected from two different coastal regions of Spain. One group of infected clams was found in Spain’s Atlantic coast. Other group was found 1,000 nautical miles away in the Mediterranean Sea.
Scientists used a technique named whole-genome sequencing. They wanted to reveal the cancer originated in a single clam which later spread among warty venus clams. The cancer has genetic sequences from both the warty venus clam and another unknown species of clam. Scientists compared the unknown genetic sequence to a genetic database of bivalve species. They then identified the mystery clam as Chamelea gallina.
Further DNA testing of the cell in both clam species confirmed that the cancer had jumped from the striped venus clam to the warty venus clams.
Scientists now hope that they will carry out further studies to determine the age of the tumors in their clam specimens. They will also explore for how long cancer may have been spreading among these species.