Scientists from the University of California Berkeley are locked into a fight with the Massachusetts Institute of Technology over the rights to a new gene-editing tool that cuts DNA strands known as CRISPRs, which stands for clustered regularly interspaced short palindromic repeats.

These segments of DNA repeat their base sequences, and UC developed a new tool that could alter this sequence by turning the natural defense system of a bacteria into a gene-editing tool, according to a San Jose Mercury News report.

But researchers at MIT and Harvard were working on their own project, this one involving human cells. UC was first to the patent office with their design, but MIT expedited their proposal by paying a fee and therefore got theirs patented first despite doing so seven months later than UC. Their patent would cover CRISPR in everything aside from bacteria, including in humans.

And MIT says it’s not just because they expedited their request: they argue that they also were further along in their work, submitting lab notebooks from MIT scientists Feng Zhang to prove this. They also suggested that UC’s method had not been proven to work within humans.

However, UC is firing back by attempting to get the case reopened by submitting documents to the U.S. Patent Office, which hasn’t yet decided whether it will reopen the case. A gene editing pioneer at the University of Utah is backing UC, but they will need to convince the Patent Office to hear their pleas or there isn’t much they will be able to do to take back the patent from MIT.