Robert Field, professor of Law and Health Management and Policy at Drexel University, said the "ability to create new life forms may be emerging from the world of science fiction."
But such advances come with uncertainty, Field said. "Will everything we create be benign, or is Frankenstein now in the realm of possibility?"
Mark Bedau, professor of Philosophy and Humanities at Reed College in Portland, Ore., also writing in the Nature commentary, called the new species "a normal bacterium with a prosthetic genome."
The importance of the finding, he argued, is that such a prosthetic genome is not limited -- as the watermarks inserted by Venter and colleagues demonstrate -- to what's found in nature.
Because of that, scientists now have "an unprecedented opportunity to learn about life" that brings with it the need for new ways of thinking about precautions and risk analysis.
Indeed, Venter noted that he and colleagues were stalled for several months because one of the pieces of DNA they painstakingly crafted had a type -- a single base-pair deletion -- that means the whole chromosome could not function.
"So accuracy is essential," he said. "There's parts of the genome where it can't tolerate even a single error and there's parts where we can put in large blocks of DNA and it can tolerate all kinds of errors."
Despite that sensitivity in the lab, Venter told a reporter "it's not clear there are any" downsides to the research. Although all technologies are "dual-use," he said he thinks the work is a "linear advance" in the ability to harm and an "exponential advance" in potentially beneficial science.