Monday, April 9, 2012

New method tracks down people's DNA profile

When analyzing the sequence of someone's DNA, the information is often kept secret due to privacy reasons. So far, it has been necessary to directly analyze the genetic code to gain information about the sequence and the secrets it bears about physical characteristics. Scientists from Mount Sinai Medical Center have found a way to use another source of information to infer the structure of the DNA. It shows that privacy regarding your genes may not be so tight after all. The method can also be used to track down disease, however.

To get information stored in the DNA to the place in the cell where they make proteins from it, an intermediate is necessary: DNA sits in the core of the cell and cannot move to the protein-producing factories. An intermediate form of genetic code, called RNA, is formed by 'reading' the DNA sequence and creating a mirror image, albeit with some slight modifications. This RNA structure then moves out of the cell core, or nucleus, and provides the information to the protein-producing ribosomes, that use it as a blueprint. Experiments have shown that RNA can be used to derive the corresponding DNA sequence, and it is possible to recreate a person's genetic code.
By using readily available pieces of tissue, scientists have shown capable of reconstructing the DNA of many people. By looking at the level of RNA expression in tissues, they were able to create a so-called barcode that can be uniquely tagged to a DNA sequence. According to the scientists, it does not matter which tissues are analyzed, as they are all capable of yielding the structure of the DNA.

While scientists could simply be analyzing the structure of the DNA instead of fiddling with RNA, the newly published method has deeper consequences. Many governments have applied privacy regulations to information about individual DNA sequences, but these laws do not apply for RNA. Because scientists often take tissue samples in research, it is potentially possible to derive the DNA structure of many people and thereby recognize the individuals it belongs to. The findings show that protecting information about someone's genetic sequence is not that easy, and perhaps the privacy laws need updating. Forensics also gain more tools to discover someone's identity, for example after a murder.

In addition, using RNA to infer information gives us more possibilities. According to the scientists, it is also possible to use RNA expression patterns to discover someone's age, sex, or the chance of getting a certain disease. Certain genes are known to cause cancer, and the level of expression, as measured by RNA, tells us something about how active a gene is. Therefore, the analyzing technique can also be used in a clinical setting for disease predictions, but also for deciding which therapy works best.

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