Researcher and Geneticist from the University of Oxford, Jonathan Flint, has successfully produced evidence of the link tying depression and genetics together. His study shows the first ever proof of two genetic markers linked to a major depressive disorder.
Depression is not as cut and dry as one may assume. This has made it very difficult for scientists over the years to accurately pin-point a genetic link between the two. Mr. Flint did not have high hopes for finding the link when he first started his research a few years ago. This was mainly because many researchers have attempted to find the exact same thing but all came up short a conclusive finding. In fact, when Mr. Flint began the most recent study, the odds were so high against his actually finding the link, he didn’t even think it a possibility. Fortunately for Mr. Flint and the team of researchers assisting in the study their efforts to find genetic sequences linked to depression were a success.
Flint was joined by renowned psychiatrist Kenneth Kendler of Virginia Commonwealth University in Richmond and an extensive team of collaborators. They decided it best to do the study in China because of the large population living there and the fact that depression is known to be very under-diagnosed in that region. To reduce variability even further, they decided to only study Chinese women of Han Chinese ethnicity(1). The efforts to reduce variability were necessary due to the unsuccessful attempts made in previous studies where large groups of people were analyzed.
The researchers analyzed DNA sequences from 5,303 Chinese women with depression as well as another 5,337 control subjects in the study. They found that 85% of the depressed women had a severe form of the disorder called melancholia.(1) Melancholia robs people of the ability to feel joy. An example would be if a proud grandpa was to be unexpectedly surprised by his favorite grandchild, but yet would not feel anything. No surprise, no joy, no happiness-nothing.
What the researchers learned was that results from their analysis of the DNA sequences yielded two genetic sequences; one coded for an enzyme whose function is unknown and the other next to the gene SIRT1. The SIRT1 gene is important for energy-producing cell structures called mitochondria.
The discovery of these two DNA sequences in people suffering from depression will be further researched and will most likely guide biologist to aid in depression diagnosis and new methods of treatment for sufferers.
Read the study published in Nature here.
(1) Nature 523, 268–269 (16 July 2015) doi:10.1038/523268a Retrieved from, http://www.nature.com/news/first-robust-genetic-links-to-depression-emerge-1.17979