Does the media sensationalize terrible science? Oh, yes.

The other day, I was drinking a glass of wine with a friend of mine, and she mentioned a story that she recently read in Scientific American called “Changing Our DNA Through Mind Control.”  She was excited to tell me how scientists had found that decreasing your stress can actually change your DNA! This was fascinating!  She was excited!  I was excited!  But being the scientist that I am, I wanted to understand what, how and why, so I needed more information. To gather this information, I looked at the original scientific article in the journal Cancer. (see here for my post on what a scientific article looks like).

om

Thank you Wikipedia for the image

The researchers had taken breast cancer patients and split them into two groups – one group went to mindful  meditation classes and the second group did not.  The scientists then took a sample of their DNA isolated from the patient’s blood and tested the length of their chromosome’s telomeres. To remind you, all people have 23 pairs of chromosomes in each and every cell. Telomeres are found at the ends of the chromosomes and protect the chromosomes from being damaged (essentially eaten away at from the ends by DNA-chomping proteins inside the cell).  A common comparison is to think of telomeres like the plastic bits at the end of shoelaces. The shorter the telomeres (or the shorter the plastic bit), the closer the chromosome (or the shoelace) is to being damaged.   In this study, the researchers found that the telomeres in cancer patients who went to meditation were longer than the patients that didn’t . Because of this, their DNA was better protected.  How incredible!

How unbelievable. Unbelievable for a few reasons:

  1. The researchers looked at the length of telomeres over a three month time span.  Telomeres shorten over a lifetime, so I wouldn’t expect to see a significant change over 3 months (whether sick, well, stressed, or not stressed).
  2. Because of this reasoning, I looked carefully at the data they presented in the paper.  None of it was statistically significant.  There is a trend that showed that patients that did not go to meditation were slightly, on average, a tiny bit lower than patients that went to mediation, but nothing that convinces me that what they are seeing is real,  In fact, even the paper’s authors said that if they wanted to have enough patients to get to statistical significance in the results, they would need to do a bigger study with more than double the number of participants.
  3. As a final nail in the coffin, in the psychological analysis comparing the mood of the meditating versus non-meditating patients, the researchers didn’t notice a change in stress or mood scores.  So even if there was a change in the DNA (which there isn’t), since their mood doesn’t change, a decrease in stress cannot be the cause of the telomere/DNA changes.
I’m not saying that mood doesn’t have the ability to affect your DNA – maybe it does.  I just don’t think that they showed it in this study.
chocolate

Thank you Wikipedia for the image

But I don’t want to harp on these researchers or this study. In fact, here’s another interesting example. A science journalist, Dr. John Bohannon, recently wrote a scientific article based on an actual study that they did studying people’s diet and how chocolate contributed to their weight loss. They found that eating chocolate once a day significantly increased weight loss!  The data was real, they published the results, and the media picked it up like wildfire.  It was published by news media around the world!!! Only problem – the conclusions they they drew were crap, and Dr. Bohannon published them with the intention of baiting the media.  In this case, there were too few participants, so they found something that was “statistically significant” in this group of people but wouldn’t necessarily pan out if there was a full, well-designed study. John Bohannon wrote a great blog post about this whole experiment and why this is the case.

So what’s the message here?  I think the first is that the media often looks for science that can create a striking, head-turning headline.  The problem is that when the conclusion is so cool, journalists don’t always read the original article or evaluate the data to make sure that this cool headline is supported by evidence in the publication.  To be fair, journalists may assume that since other scientists already reviewed the paper for scientific accuracy (a process called “peer review”) that it will be good to go.  But just because a stranger hands you a drink in a bar and says its okay, should you just believe them that it doesn’t contain Roofies?  I also don’t want to imply that all science journalism falls into this trap, but with ever shortening deadlines and competition for the “hot headline,” I can only imagine how appealing it is to take shortcuts.

To conclude, I actually have a problem in writing this post in that I don’t have a solution for you, my reader.  Unlike the friend I was having drinks with, you may not have a scientist at your beck and call to vet all news stories for scientific accuracy.  And as much as I hope that this blog is helping you to obtain your own PhD in biology, you won’t have all the tools you need to evaluate scientific articles on your own.  So maybe I will leave you with a tried an true saying “Don’t believe everything you read” or maybe “If it sounds too good to be true…” it might be.

I’m not the only person who has written about this topic.  If you’re interesting in reading more, check out this article from NPR, numerous articles from Ben Goldacre about how science is misrepresented in the media compiled on Bad Science, and a different point of view, an article published in Salon about how just because someone is a scientist doesn’t mean that they are an expert (especially if they are on Fox News).

What is my genome? And does size matter?

I would be interested in knowing how often the popular press has used the word “genome” in the past year (I couldn’t find this kind of study, but let me know if it exists).  What I could do was look at the scientific literature and see how many times the word “genome” was used in all scientific publications ( here’s how you can do that). The answer: nearly ONE MILLION TIMES.  Each year for the past six years, the word has been used in over 40,000 publications. The genome is kind of a big deal in science (for comparison, the word DNA has been used 1.3M times) and it’s a big deal to you!

genome publications

We’ve already talked about what DNA is here, but how does that relate to the genome? The genome is made up of all the DNA in a organism.  Every single cell in your body (except maybe red blood cells, which shove the DNA out of the cell as part of the process of becoming a red blood cell) contains a copy of your entire genome.  Genomes aren’t just in humans.  Every living organism from a bacterial cell to a mushroom to a squirrel to your pet fish or dog or cat or bird, all has a genome.

In humans, the genome is made out of 22 pairs of chromosomes and 2 sex chromosome.  The 22 chromosomes are conveniently named chromosome 1, chromosome 2, chromosome 3…etc.  The two different sex chromosome are named X and Y. Men have one copy of X and one copy of Y (XY) and women have two X chromosomes (XX). You can actually isolate all of the chromosomes and view them using a stain in a process called karyotyping (see the image below).
chromosomes

Chromosomes are made up of DNA.  Each of the chromosomes you see above is a long string of As, Ts, Cs, and Gs twisted and curled up so that the strand gets big and thick enough to see. Here’s a way to think about this – imagine the DNA strand is one strand of your hair.  If you take the hair by the ends and twist it between your fingers, it starts to rotate and curl and twist until the strand is much thicker and shorter than the long skinny piece of hair.  That’s what DNA does (with a little help from some friends called histones).  Why does DNA do this?  So it fits inside of your cells.  The human genome is more than 3 billion bases (bases are those As, Ts, Cs, and Gs,) and if stretched from end to end would be 6-10 feet in length.  The largest human cell (the female egg) is 120 micrometers in diameter, which is 0.0004 feet.  See now why reducing the size of the DNA is so important?

Paris japonica Kinugasasou in Hakusan 2003 7 27″ by alpsdake – Own work. Licensed under Public Domain via Wikimedia Commons

And because it’s always about size, let’s talk about the size of the human genome.  Think it’s the biggest?  Not by a long shot.  The plant paris japonica has 40 chromosomes and 150 BILLION bases (that’s 50,000 times the size of the human genome, in case we’re counting).  And this is only of the genomes that we’ve looked at.  So moving forward, keep in mind it’s not the size of the genome that matters, it’s what the genome does with what it has that matters.



** The majority of scientific literature is stored in an online library managed by the National Institutes of Health called Pubmed. You can search for nearly any scientific article based on any keyword or author. So for example, the Pubmed search for the word “genome” is here. You may or may not have access to the full text of the publications that are listed on Pubmed (the debate about scientific publishing and WHY all the publications aren’t freely available to everyone is a long and contentious one, but you can check out some of the discussion in a recent special issue of Nature).  However, there is a version of all publications funded by public money called Pubmed Central. Search here and you can read all of the scientific publications that have been made available – including the 542,069 publications that have the word “genome” in them.