Nayanah Siva in Nautilus:
The scientists crowded around Yuanchao Xue’s petri dish. They couldn’t identify the cells that they were seeing. “We saw a lot of cells with spikes growing out of the cell surface,” said Xiang-Dong Fu, the research team’s leader at the University of California, San Diego. “None of us really knew that much about neuroscience, and we asked around and someone said that these were neurons.” The team, who were made up of basic cellular and molecular scientists, were utterly puzzled. Where had these neurons come from? Xue had left a failed experiment, a dish full of human tumor cells, in the incubator, and when he looked two weeks later, he found a dish full of neurons.
It’s not often an unexpected cell type appears in a petri dish, as if from nowhere. Scientists all over the world have spent a lot of time and money actively trying to generate neurons in the lab—the implications for neurodegenerative disease would be massive. And yet this research team, who were actually studying the RNA-binding protein PTB, had unknowingly generated a whole dish of neurons.
“It puzzled me for quite a long time, and I didn’t know what was wrong with my cells,” said Xue, who is now a researcher at the Institute of Biophysics at the Chinese Academy of Sciences, in Beijing. Xue was attempting to deplete human tumor cells of PTB with small interference RNAs (siRNAs). He expected his cell lines, which are typically very proliferative, to keep growing, but they stopped, and so were cast aside for two weeks. Sure that the dish had become contaminated, Xue and colleagues tried the experiment again … and again … and again.
More here.