It strikes me that for many people here, some description of the processes involved in the extraction of BRCA1, highlighting where those procedures were developed (and potentially first patented) may be useful. The process is basically as follows: 1) extract some material containing DNA. This may be saliva, blood, cells from the skin, or a sample from a biopsy (or any of a myriad of other sources) 2) Isolate the cells containing the DNA. This varies depending on the sample type. For blood, you spin it and take off the layer (called the "buffy coat") containing lymphocytes. 3) Release the DNA. In this process the cells are lysed, a process which destroys membranes and causes the contents of the cell to spew forth. The main cell wall, and the wall of the nucleus are the main targets here. 4) Purificaton of DNA. The DNA is purified and separated from all the other stuff we don't want. 5) PCR amplification. The DNA, a pair of primers (small pieces of DNA that bracket the area you're interested in), polymerase (an enzyme that replicates DNA) and nucleotides (the individual "letters" making up a DNA sequence ae combined with some other things that are not particularly important here, and a series of repeated heating and cooling is applied which causes the string of DNA between the primers to be replicated over and over again. 6) Purification. The amplified sequences are separated from the rest of the DNA, polymerase, nucleotides, etc. 7) Sequencing reaction. The DNA is mixed with another primer, nucleotides, and special terminators. and more polymerase. A similar sequencing reaction occurs as above, but when a terminator gets added to a sequence it can no longer be extended. This happens randomly, generating fragments starting at the "beginning" of the sequence and of every length up to and including the full length of the original fragments. 8) More purification (all we want are the terminated fragments) 9) measuring the length of the sequences. A sequencer essentially measures the length of these fragments and identifies the terminator on the end. Thus I can determine that a length of 10 ends with a C, of 11 ends with a G, of 12 ends with a T, and so on, giving me the sequence CGT... This is an overly simplistic description, but it will put a few things into sharp focus. a) PCR (step 5) was first described in 1968, but was made into a practical method in 1884. b) Sangar sequencing (steps 7 to 9) was developed in 1974. Whilst his method is no longer used, similar methods are typically referred to generically as "Sanger sequencing". c) the steps 1 through 4 have been known for a long time, I won't even try to find references for who discovered them. The various "purification" steps used in the process are very similar in nature. d) An important discovery were high temperature polymerases (found in extremophiles living in near-boiling water) This leads to polymerase often being called "taq", an abbreviation of Thermus Aquaticus, the bacteria from which this polymerase was extracted. So what part of this process has Myriad discovered? The answer is none. They have identified a small part of the genome that they are interested in, and developed a pair of primers (probably more than just a pair) that bound it. They then claim that anyone using the above process (or one similar to it) and using their primers is infringing on their patent. In fact, they don't even care if you use this process -- just ending up with the same result is enough. Just to be clear... The result from this process is a small piece of DNA clipped from the genome. In the case of cDNA it's just more than one piece where they are *EXPRESSED* as if they were connected together (but they're not actually connected -- they're separate pieces). More clarification... DNA is a bit like computer code with labels an goto's. Typically the labels mark the start and end of the "program" (the gene) and the goto's only jump forward. The pieces through which you would execute are called the EXONS and they get converted to peptides. The pieces that are jumped over are called INTRONS and at this level we can consider them to be like lines of dead code that is never executed. Genomic DNA (gDNA) is what you get when you list the entire program (including all the dead code). cDNA is what you get if you follow the program counter and note down only the lines that are executed. Now, to be sure, finding the piece of DNA and determining it's function was non-trivial. Perhaps even the design of the primers was non-trivial. But the end process? It's the bread and butter of sequencing labs all around the world. Almost anyone in those labs could now extract that gene. Once you know where it is, it requires no more than the skills of someone with average knowledge in the field to define the primer, and an even less skilled person to extract it. I am not even skilled enough to do PCR, but I have written software to suggest possible binding sites (and hence primer sequences) to extract regions of DNA from larger genomic sequences (human genome project anyone?). So why do they want to patent the result and not simply copyright the primers? The answer is that primers are not as critical as you might think. You can change a base here and there, you can lengthen or shorten them, you can move them a bit, and they will still continue to do their work. In addition, you can't make their location secret. ---

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That's not a law suit. *THIS* is a law suit! [ Reply to This | # ]

