How Genes Shape Personality Traits

 Yale School of Medicine- How Genes Shape Personality Traits: New Links Are Discovered

A study by the Yale School of Medicine was conducted to connect how the loci of different genes influence an individual's personality, specifically the “big 5 personality traits”. An article, entitled “How Genes Shape Personality Traits: New Links Are Discovered”, covers one of the largest genetic studies of DNA and its influence on personality. Using genetic data from the Million Veteran Program and a total of 700,000 individuals, researchers worked to understand the connection between gene loci and their effect on the Big 5 personality traits. The big 5 personality traits include extraversion, openness, agreeableness, neuroticism, and conscientiousness. From this data, Dr. Levey's team was able to discover 62 new loci associated with neuroticism and discovered the first loci associated with agreeableness. Meta-analysis techniques enabled the team to connect over 200 loci with the five major personality traits. Working to apply these discoveries to a larger sample size, Dr. Levey is hopeful to identify a precise definition of variation in his findings. To apply these findings to a broader scale, the research team connected personality traits with mental health issues. While most of the connections made are well established, the team's research was still able to provide a genetic background to each correlation, offering a possible explanation for why some people suffer from different mental health diagnoses according to their personality. Looking towards the future, Levey's team is hopeful that understanding the genetics behind one's personality may give way to the prevention of certain mental health issues. They explain that just because personality is genetically determined, it doesn't mean an individual cannot change certain aspects of their personality. Another article, published in the National Library of Medicine, discusses personality traits and genetics but applies these ideas to family and the study of inheritance. These researchers gather that the application of genetic data to biology and psychology is not as straightforward as it may seem. However, they are hopeful that studying the genetic basis of personality will give more insight into the biology of personality disorders. 

Applying the study of genetics and inheritance to an individual's personality is not only important, but provides insight into potential mental disorders a person might encounter. The idea that a gene location may alter an individual's personality trait and ultimately life is fascinating. This study found major connections between different personality traits and mental health disorders, rendering these findings crucial for psychologists. With hopes for these findings to go deeper in the future, they must include a more diverse and wider group of people. With this larger sample population, different variations will be considered, altering conclusions and providing deeper insight into what was discovered in both studies. 

The Genetic Architecture of Bipolar Disorder

      The National Institute of Mental Health recently conducted a study on a diverse demographic of people who have bipolar disorder, and those who don't. It currently is the largest genome-wide study of bipolar disorder, with a total of 158,036 people with bipolar disorder and 2,796,499 people without the disorder. People across the globe took part in the study, and roughly 300 gene locations and 36 unique gene locations were identified and believed to be linked to the disorder. The heritability of the disease is very high, with reports of it being as high as 60-80%. Researchers believed the differences in genetic ancestry and bipolar disorder subtypes can lead to the different genetic architecture of bipolar disorder. 

It was discovered that there were exactly 298 significant bipolar disorder associated loci, an increase in discovery of bipolar disorder in comparison to previous findings, and an ancestry-specific association in the East Asian cohort. Bipolar disorder can be very polarizing due to the stigma surrounding it, even with 2.8% of American adults being affected by it. Many of the genetic and environmental factors effecting bipolar disorder were shared among individuals with the condition. The genetic architecture of bipolar disorder is different because it's heavily affected by the concentration of the subtype present. Hopefully through the use of linkage maps, more studies can be done on the loci associated with bipolar disorder and the possible prevention for it. 

GWAS Shows Correlation of Cannabis Use Disorder with Lung Cancer

 The Genetic Basis of Cannabis Use Disorder and Lung Cancer

    A recent GWAS from Nature shows a correlation between lung cancer susceptibility and cannabis use disorder. This study was a meta-analysis between nearly 1 million individuals of European, African, mixed American, and East Asian ancestries and it examined single nucleotide polymorphism (SNP) heritability. Using this data, the researchers found that 22 loci were associated with the susceptibility of lung cancer, but in each group, the expression of the SNPs was different. For instance, the East Asian sample group's SNPs were intronic to the semaphorin 6D-encoding gene, whereas the American group was an intergenic region downstream of leucine-rich repeats containing the semaphorin 6D-encoding gene. They used a comparative analysis of psychiatric symptoms and found many overlapping associations between cannabis use disorder and the likelihood of developing lung cancer. This association comes from a likelihood of becoming a smoker and resorting to cigarettes, which would most likely, in turn, result in a greater risk for lung cancer in those populations.

    I found this study to be very interesting and it definitely shines some light on the addictive manner of cannabis and cannabis-containing products. The biological mechanism of cannabis and the cannabinoids involved are still not fully known, which I think is a long-term danger in regards to smoking/consuming cannabis products. Furthermore, those with cannabis use disorder being at a greater likelihood for developing lung cancer is scary to think about and could considerably be an element of medicine/psychiatry to dig deeper to in the meantime. Nevertheless, going forward I think we should be more conscientious of what we are breathing in and consuming, because with lung cancer being the top cause of death, that should be enough to scare us into treating our bodies better. 

Links:

1. https://www.nature.com/articles/s41588-023-01563-z 

2. https://www.news-medical.net/news/20231123/Genome-study-unveils-genetic-ties-between-cannabis-use-disorder-and-lung-cancer-risk.aspx 

Come On Get Happy

There is an article that is a bit older, but still very interesting, from Science Magazine. Scientists have been working finding the genetic variants that are associated with mental illness. A GWAS (genome-wide association studies) was conducted on a group of African Americans to try and find the loci that may be responsible for an inheritable trait of happiness. They were able to identify a specific loci that was strongly associated with an individual with more positive emotional experiences.

Genetics is incredible in the fact that every day that passes we learn a little more. I find it fascinating that so many traits, which are not limited to physical traits, are determined by an individual's genetic coding. I am eager to see how the identification of these genes in conjunction with advances in gene therapies; changes how much of the inherited self can be modified.

New clues to genetics of depression are 'game-changing'

     Recent research has identified 44 gene loci with significant association to depression. The analysis involved nearly 135,000 people with major forms of depression and more than 344,000 controls. And of those 44 loci found, 30 of them were new discoveries. With the other 14 having been identified in previous studies. That is roughly 70% of the loci being newly discovered. In addition to this, there was also another study done in Nature Genetics. In which they identified 153 genes and also found that depression shared six loci associated with schizophrenia. The study has been described as "a game-changer" by study co-leader Patrick F. Sullivan. The study shows that all people carry genetic variants for depression, but some people's are just higher in volume. Thus resulting in major depression. 

     There were a number of other findings in this study. Including ways to improve therapies because known antidepressant medications were enriched in the genetic findings. The researchers also found that the genetic basis of depression had overlaps with other psychiatric disorders such as bipolar disorder and schizophrenia. The basis also has overlaps with obesity, daytime sleepiness, insomnia and tiredness. I believe this is important in today's society as depression as become somewhat of a 'silent killer' in the United States. As depression usually leads to suicide. Reducing the affects of depression could save a lot of lives. 

Article Link: https://www.futurity.org/44-genomic-variants-depression-1741752-2/

Nature Genetics study: https://www.nature.com/articles/s41588-018-0090-3