DNA- Recent studies show it may not be as good a tool as we thought

      

      DNA has become a very powerful tool in forensics in the last few years. Many people have been connected to crimes that had previously gone unsolved and others have been completely cleared of wrongdoing. This is mostly because we assume that each person not only has a unique genome but only has one genome. What if this wasn't the case though? What would that mean for forensics?

What if we don't just have one set of DNA?
      According to the article "DNA Double Take" by Carl Zimmer published in the New York Times, scientist are finding people who have multiple genomes contained in their bodies. Essentially a single person has two sets of DNA. These people, according to the article, are known as chimeras. They can receive the multiple genomes in a number of ways. One way that they may get the second genome is from a twin in the womb from sharing blood vessels. The article talks of a woman who "donated a pint of blood... it turned out some of her blood was Type O and some was Type A." This woman, it turned out, had been a twin and the other blood type present in her body was her twin brother's blood type.

A second way a person may receive a second genome involves women who have been pregnant receiving fetal DNA from their children that integrates itself into the mother's body. In fact one researcher said "It's pretty likely that any woman who has been pregnant is a chimera." One other way that people can end up containing two sets of DNA is through what is called mosiacism. Essentially, the article explains, a cell somewhere in the body mutates drastically and this completely changes the genome of that cell. The cell then replicated resulting in some cells with the original genome and others with the new genome.


So what does that mean for forensics?                                      DNA test
      This could potentially be a bit worrying for forensic scientists especially in cases were DNA evidence is the main source of evidence for the case. It could potentially cause doubt as to the validity of DNA tests and can end up resulting in false positives on some occasions. These finding do cast some doubt as to whether or not DNA is as good a tool as was once thought. However according to Manfred Kayser, a molecular biology professor, "this should not be much of a concern for forensics," since the scientists have other ways of confirming if the DNA they are testing is the correct DNA. The only real problem I can see is that it may make it easier for defense attorneys to challenge DNA tests but hopefully it will not be too big of a problem

Can we trust the source?
     All of the people that contributed to this research and the article itself are highly respected in their field. The author has published numerous scientific articles for the New York Times. He uses scientific language that is accurate but still understandable to the general public, though it is likely that he assumed that the person reading this article is well educated since it is the New York Times and their readers do tend to be more well educated.  Not to mention the New York Times is a very reputable, highly respected publication. The author gives examples of how this phenomenon can occur rather than just stating that it can which does add further credibility to the article.

      The article is well written and grammatically correct which does lend credibility to it. It also does not overly stress one side or the other of the issue. The author is not particularly distressed about either side. He just gives the facts and allows you to draw your own conclusions. There is no emotional appeal to the reader to feel one way or another about this issue. I think this is a good thing when the topic is scientific as it allows the reader to make decisions based on the facts rather than emotion. I would say it is quite trustworthy. Here is the link if you are interested in reading more from the article where I got this information from.
            http://www.nytimes.com/2013/09/17/science/dna-double-take.html?pagewanted=2&ref=forensicscience