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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.