- In a decision that could have broad-reaching effects on the future of science and medicine, the Supreme Court ruled Thursday that:
— "A naturally occurring DNA segment is a product of nature and not patent eligible merely because it has been isolated."
— But, synthetically created "strands of nucleotides known as composite DNA (cDNA)" are "patent eligible" because they do not occur naturally.
It depends. The statement that cDNA are not naturally occurring is false. Our cells don't create cDNA, but some viruses do. The typical flow of gene expression in our cells is this: IMO it would be pretty lame to grant a patent on the cDNA of a naturally occurring gene. Because: 1) a retroviruses have probably already created copies of it, so it is naturally occurring, and 2) anyone studying that gene is going to need to make its cDNA as a matter of course. It would be really chilling if someone patented a cDNA, then looked through the literature for anyone that was preforming RT-PCR on its base gene, which basically everyone that studies the gene must do. We will see how it plays out. The first decision is common sense. It's absurd that it had to take the SCOTUS to finalize that. IMO, the second decision is not great, but it might have little practice effect.
However, the copy from DNA to mRNA isn't exact. Some portions of the DNA are excised and not copied. If you want cDNA, you do this: DNA > mRNA > Proteins
Where that last step is called 'reverse transcription'. In the lab, we do it all the time. Most often, it's one step in something called RT-PCR (Reverse transcription polymerase chain reaction) which we perform to measure the quantity of an mRNA, which tells us how actively a gene is being expressed. DNA > mRNA > cDNA