Many scientific breakthroughs begin as accidental discoveries. This was the experience of DTU researcher Zoltan Szallasi from DTU Systems Biology and a Hungarian research team who—much to their surprise—discovered, among other things, tomato DNA in the blood samples of cancer patients. This simply should not even have been possible.
While sequencing cancer patient blood samples, the researchers noticed that much of the DNA did not belong to the human genome. At a meeting, the researchers got the idea of comparing the foreign DNA particles with some of the genome data currently available in various databases. To their great surprise, it turned out that much of the DNA originated from foods such as tomatoes and potatoes.
“Our first thought was that we must have made a mistake because the standard paradigm is that macromolecules such as proteins and DNA from foods cannot find their way into the bloodstream,” explains Zoltan Szallasi. “But when we checked the results with other blood samples from other studies, we got the same result. Long strands of DNA from the food we eat can actually be present in a subsequent blood test.”
It was Zoltan Szallasi’s colleague from Centre for Biological Sequence Analysis, DTU Systems Biology—Thomas Sicheritz-Pontén— who first identified the link between the DNA from the blood samples and genes from, among other things, tomato chloroplast.
Genome data analysis expert—Thomas Sicheritz-Pontén—explains that scientists are currently making many of these kinds of surprising discoveries—and the reason for it.
“First and foremost, we now have the necessary computer power to do in days what used to take years to calculate. Also, leveraging new technologies such as next-generation sequencing, we can get reliable sequence data from even the smallest quantities of DNA at an ever lower cost. The result is a data explosion made available through public databases. So now the big challenge is understanding what these data mean,” says Thomas Sicheritz-Pontén.
According to the researchers, it is still too early to predict the consequences of food DNA in the bloodstream.
“We need to find out how the molecules slip through and then determine the human consequences of digesting DNA from the food we eat,” says Zoltan Szallasi.