The Supreme Court ruled Thursday that companies cannot patent parts of naturally-occurring human genes, a decision with the potential to profoundly affect the emerging and lucrative medical and biotechnology industries.

The high court’s unanimous judgment reverses three decades of patent awards by government officials. It throws out patents held by Salt Lake City-based Myriad Genetics Inc. on an increasingly popular breast cancer test brought into the public eye recently by actress Angelina Jolie’s revelation that she had a double mastectomy because of one of the genes involved in this case.