Short answer is the first sentence on page 2. Basically if it exists on its own, it is not patentable. If someone makes it, it is patentable.
Wade through the page 2 and the paragraph on page 3, which is the summary. That should give you a basic understanding of the decision and basis.
If you know genetics you can understand most of the rest of it. Otherwise trust me.
Nemo
Held: A naturally occurring DNA segment is a product of nature and not patent eligible merely because it has been isolated, but cDNA ispatent eligible because it is not naturally occurring. Pp. 10?18.
