On Thursday, the Supreme Court ruled than human genes cannot be patented, a victory for medical research, particularly in fields centered on genetic disorders.

In a unanimous decision, the Court invalidated patents on short segments of the human genome, which some biotech companies had claimed they owned, requiring other companies and research organizations to pay fees to conduct studies or treat patients with particular genetic mutations.

The case centered around Myriad Genetics, which had a patent on BRCA1 and BRCA2. Particular mutations of those genes put women at much greater risk for breast cancer, and some women who carry the mutations, like Angelina Jolie, choose preemptive treatment, like mastectomies.

But tests to detect the presence of the mutation had been subject to licensing fees owed to Myriad, and further research into the genes also needed to fund payments for the rights to use genetic material found naturally in millions of people around the world.

"Myriad did not create or alter either the genetic information encoded in the BCRA1 and BCRA2 genes or the genetic structure of the DNA. It found an important and useful gene, but groundbreaking, innovative, or even brilliant discovery does not by itself satisfy the §101 inquiry," wrote Supreme Court Justice Clarence Thomas in the unanimous opinion, referring to a requirement of the law governing patentable discoveries.

The justices' decision rested on a provision of patent law that prohibits the granting patents on naturally occurring substances, as they can only be discovered, not created.

"The Patent Act permits patents to be issued to '[w]hoever invents or discovers any new and useful . . . composition of matter,' §101, but 'laws of nature, natural phenomena, and abstract ideas' 'are basic tools of scientific and technological work'' that lie beyond the domain of patent protection," Thomas wrote.

The ruling states that human genes are naturally occurring, and therefore not subjects to patents, no matter how many resources a company spends to isolate or identify a particular gene sequence.

The ruling still allows companies to patent processes or techniques derived from human genes, or even patent new genes created by studying human genes, just not the unaltered genes themselves.

The decision has far-reaching consequences for biotech research, as well as many patients with genetic disorders, who will now have to pay less for tests and procedures.