Slashdot Mirror

← Back to Stories (view on slashdot.org)

DNA Differences Observed Between Blood and Organs

Posted by kdawson on from the same-old-same-old dept.

Scrameustache writes "Researcher working on a rare type of aortic abnormality found that the DNA from diseased tissue did not match the DNA from the blood of the same patients So far it's unclear whether these differences in the blood and aortic tissue are the consequence of RNA editing, which changes the messenger RNA but not the gene, or DNA editing, which involves differences in the gene itself. Based on the evidence so far, the researchers believe the differences resulted from developmental rather than somatic DNA alterations. 'Traditionally when we have looked for genetic risk factors for, say, heart disease, we have assumed that the blood will tell us what's happening in the tissue,' lead author Bruce Gottlieb said in a statement. 'It now seems this is simply not the case.'"

4 of 85 comments (clear)

  1. title misleading (again) by dltaylor · · Score: 4, Informative

    The researchers did NOT say, definitively, that the patients DNA varied between blood and aorta.

    What they said was that the SEQUENCING showed a difference. The sequencer used cannot distinguish between messenger RNA and DNA differences.

    While it is possible that micro-environment, such as being blood vs. being aorta could result in changes to DNA, it is far more likely to result in tweaks to messenger RNA.

    Since they found the same SNPs in aortic tissue from the organ bank, it could just be a common adaptation for that tissue.

    1. Re:title misleading (again) by rnaiguy · · Score: 4, Informative
      While you are technically correct, you missed the point entirely.

      If you read TFA (not the news piece, the actual one), then you will see that they sequenced cDNA, which means that they have the RNA sequence, but NOT the DNA sequence, and therefore cannot tell whether the changes occurred at the DNA or RNA level (such changes occurring at the RNA is old news). The GP did not quite express this clearly, but is correct in spirit.

      What I cannot fathom, is why they did not simply sequence the DNA of their gene of interest (really just the area around the mutation(s)) for a few patients. This would be really straightforward (can be done in a week), and i woud have thought any reasonable peer reviewer would request it. Overall, there is not enough evidence to support the hype in the news piece, as far as I'm concerned, which explains why it's not published in a high-end journal.

  2. Re:good old days by Anonymous Coward · · Score: 4, Insightful

    Not all mutations are "all good" or "all bad". Granted, many are instantly fatal others cancerous, and some serve no known purpose. But to propose that we should limit the genetic diversity to include only genes that we currently think are "good" is foolhardy. Our species - or it's descendants - are best served by having a large base of mutations in the inventory. This way, when nature throws us a curveball, we may have an existing population of humans with the genetics to survive. For example, there are supposedly some tribes in the Amazon who have a mild form of Cystic Fibrosis, which prevents them from sweating their salt out. It seems like a bad idea, until you consider they are living in an extreme environment where sweating is a poor method of cooling due to the high dew point, and it would kill most "healthy" people who lived there. Malaria resistance is improved by being a heterozygous carrier for sickle cell anemia. Et cetera.

    As for your link, I see your IMDB and raise you an XKCD (http://xkcd.com/603/).

  3. Re:Chimera by broken_chaos · · Score: 4, Informative

    http://en.wikipedia.org/wiki/Chimera_(genetics)

    The name comes from the mythical chimera, but is actually an organism (humans can possibly have this) with two or more distinct types of DNA in it's body. For example, if a human had one set of DNA in their kidneys and a different set in their liver.