Supreme Court Justice Antonin Scalia admitted he doesn’t really understand it. Justice Clarence Thomas wrote an entire court opinion implying—unconvincingly, to scientists—that he does. And, as of right now, there’s still nothing stopping you from filing patents on it. Meet complementary DNA (cDNA), the confusing molecule at the heart of the recent Supreme Court ruling on DNA patents.
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The case, ruled upon in june, was hailed as a victory over efforts to turn the human genome into corporate property. But the ruling may not be the smackdown of gene patents that it appeared to be, and cDNA is where much of the uncertainly lies. Big questions remain: What is cDNA actually being used to do? Why does it matter who owns it? And what do scientists think this debate is really about?
Steinbeck Without the Turtle
On a functional level, cDNA really isn’t all that different from plain old DNA. In fact, it’s just a slimmed down copy -- the Reader’s Digest Condensed Book version. DNA is made of up of paired sequences of nucleotides. Some of those sequences—exons—are critical to making a functioning, living thing. They provide the coding instructions that tell cells how to make proteins, and proteins do everything: muscle is made from proteins, proteins help cells communicate with one another, and they do the chemistry that turns food into energy.
Other sequences in the DNA, though—introns—just sort of sit there. You could snip them out and still make a protein, just like you could cut the chapter about a turtle crossing the road out of The Grapes of Wrath without losing any important parts of the plot. (Insert angry Steinbeck fans here.)
Essentially, that’s all cDNA is: Steinbeck without the turtle. DNA without the introns.
In the Supreme Court case, a company called Myriad Genetics attempted to patent genes known as BRCA1 and BRCA2. Mutations in these genes have been linked to an increased risk of breast cancer. Myriad developed a test to look for those mutations. But the Court threw out the company's claim of ownership over BRCA1 and 2, ruling that Myriad couldn’t patent the naturally occurring DNA that made up those genes.
But here's the catch: The BRCA genes code for proteins. In fact, that’s what makes mutations on those genes a cancer risk. Healthy BRCA genes make a protein that repairs damaged DNA, and destroys cells whose DNA can’t be fixed. Mutations prevent that protein from being made, thereby allowing damaged cells to grow unchecked. Like all protein-making genes, you don’t need the introns from BRCA1 and BRCA2 to make a functional protein. When you’re looking for potentially deadly mutations, only the exons matter. The Court said that Myriad can’t patent the DNA that contains both introns and exons, but the company can patent the exon-only cDNA.
In fact, it already claims that patent.
The case, ruled upon in june, was hailed as a victory over efforts to turn the human genome into corporate property. But the ruling may not be the smackdown of gene patents that it appeared to be, and cDNA is where much of the uncertainly lies. Big questions remain: What is cDNA actually being used to do? Why does it matter who owns it? And what do scientists think this debate is really about?Steinbeck Without the Turtle
On a functional level, cDNA really isn’t all that different from plain old DNA. In fact, it’s just a slimmed down copy -- the Reader’s Digest Condensed Book version. DNA is made of up of paired sequences of nucleotides. Some of those sequences—exons—are critical to making a functioning, living thing. They provide the coding instructions that tell cells how to make proteins, and proteins do everything: muscle is made from proteins, proteins help cells communicate with one another, and they do the chemistry that turns food into energy.
Other sequences in the DNA, though—introns—just sort of sit there. You could snip them out and still make a protein, just like you could cut the chapter about a turtle crossing the road out of The Grapes of Wrath without losing any important parts of the plot. (Insert angry Steinbeck fans here.)
Essentially, that’s all cDNA is: Steinbeck without the turtle. DNA without the introns.
In the Supreme Court case, a company called Myriad Genetics attempted to patent genes known as BRCA1 and BRCA2. Mutations in these genes have been linked to an increased risk of breast cancer. Myriad developed a test to look for those mutations. But the Court threw out the company's claim of ownership over BRCA1 and 2, ruling that Myriad couldn’t patent the naturally occurring DNA that made up those genes.
But here's the catch: The BRCA genes code for proteins. In fact, that’s what makes mutations on those genes a cancer risk. Healthy BRCA genes make a protein that repairs damaged DNA, and destroys cells whose DNA can’t be fixed. Mutations prevent that protein from being made, thereby allowing damaged cells to grow unchecked. Like all protein-making genes, you don’t need the introns from BRCA1 and BRCA2 to make a functional protein. When you’re looking for potentially deadly mutations, only the exons matter. The Court said that Myriad can’t patent the DNA that contains both introns and exons, but the company can patent the exon-only cDNA.
In fact, it already claims that patent.
by Maggie Koerth-Baker, Boing Boing | Read more:
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