The battle by Costa Rican opponents to genetically modified crops took a surprising turn Tuesday.
Researchers from Ghent University and the International Potato Institute said they discovered that sweet potatoes naturally contain genes from a bacterium, according to a summary from the university.
Unexpected, foreign genes have been seen in other crops, but in the case of sweet potatoes, researchers said that DNA sequences of Agrobacterium were very likely to be genetic transfers instead of just contamination, said the university.
The sequences attributed to the bacterium appeared to be present in each of the 291 tested sweet potato cultivars and even in some wild related species, said the summary.
“The natural presence of Agrobacterium demonstrates that genetic modification also happens in nature,” said the university. “In comparison to natural GMOs, that are beyond our control, human-made GMOs have the advantage that we know exactly which characteristic we add to the plant,” said researchers.
The bacterium must provide some desirable quality to sweet potatoes because the traits were selected by farmers for domestication, the summary added.
It is not the first time that researchers found bacterial, fungal or viral DNA in the genome of plants or animals, said the university.
Genome analyses in recent years find more and more examples of possible horizontal gene transfers in which there is exchange of genes between different species. In contrast. normal gene transfer takes place from parents to progeny and occurs within one species, it added.
Genetic modification has been a controversy in Costa Rica, in part because the U.S. giant Monsanto Corp. wants to grow a patch of modified corn for seed.
There is a bill in the legislature that proponents are urging President Luis Guillermo Solís to support and eventually sign. The bill’s wording is such that, if passed, growing sweet potatoes in Costa Rica would be prohibited, based on the findings of the Belgian university.