Science-- there's something for everyone

Thursday, June 13, 2013

Human genes can't be patented? Not so fast

Normally, I only post one story a day, but I just couldn’t wait until tomorrow for this!

Today, the Supreme Court ruled that human genes cannot be patented! Yeah! Except, they didn’t really rule that way, because the decision included this paragraph:
...but the lab technician unquestionably creates something new when cDNA is made. cDNA retains the naturally occurring exons of DNA, but it is distinct from the DNA from which it was derived. As a result, cDNA is not a “product of nature” and is patent eligible under §101, except insofar as very short series of DNA may have no intervening introns to remove when creating cDNA. In that situation, a short strand of cDNA may be indistinguishable from natural DNA.
Let me translate. 

A gene, as it exists as part of of your chromosome, contains both coding parts, which are called ‘exons’, and non-coding parts, which are called ‘introns’.  After being transcribed into RNA, the non-coding bits are removed to make mature mRNA. You can see that in the diagram below. 

The mRNA is then translated into a protein. Although this doesn’t ordinarily happen in mammalian cells, a geneticist can take that mRNA and reverse transcribe it back into DNA. This is called ‘complementary DNA’, or cDNA, and it's identical to the original gene, except without the introns. 

Thus, the court ruling says that if I chop a piece of DNA out of your chromosome, I can’t patent it. But if I make cDNA from your gene (and remember, the cDNA has all the coding parts from which I can make the original protein), then I can patent that*.  

And that’s different from patenting human genes how?

*It's been pointed out to me by David Pacheco that the Supreme Court did not specifically rule on whether cDNA is patentable, it just didn't say cDNA definitely could not be patented, as it did with naturally occurring DNA. In other words, the Court's decision may be more nuanced than I've given them credit for. Nonetheless, the ruling is far from a ban on patenting human genes as many of the headlines would have you believe.


  1. As noted in SCotUSblog, (, "the Court was not actually ruling that cDNA is specifically entitled to a composition patent, and noted that the federal government had raised other objections under patent law to that phenomenon."

  2. Thanks for bringing this to my attention, David. I still think it gives an awful lot of leeway to companies. If they can't regenerate the original gene from cDNA today, they soon will be able to. I think this ruling just pushes back the date when SCOTUS will have to make a real decision on human gene patenting. But I guess that's typical.

    1. Yes, it is pretty typical. SCOTUS likes to rule as narrowly as possible to the case in question, which can sometimes be frustrating if you want them to rule more broadly. But overall it's the more prudent approach.

  3. It isn't perfect but it is better. Already two other companies have released their BRCA gene test for $1300 and $1000, vice Myriad's $3000+. This is hugely important since many people's insurance won't pay for the test. These companies have just been waiting for this court case to be able to release their versions. It does free researchers up to find another way to get the job done.

    1. That's true. Thanks for pointing that out. I do still think this ruling is just kicking the can down the road, but it's a step in the right direction.