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Neuroscience

Does Personality Affect Genetics?

Creativity, temperament, curiosity, and compassion; these are just some of the pillars of what makes a person who they are. We must ask the question of whether personality is entirely up to us. Are we the ones driving the car to the path of identity, or is there a map? Does genetics play a role in our personality?

Creativity, temperament, curiosity, and compassion; these are just some of the pillars of what makes a person who they are. Our actions as human beings are based on personality because we are an emotional species. This emotion drives us and makes up our identity. Therefore, emotions are a result of experiences that mold your character. We must ask the question of whether personality is entirely up to us. Are we the ones driving the car to the path of identity, or is there a map? Does genetics play a role in our personality? Recent studies have shown specific genes in our DNA that significantly affect how our character is shaped.

In 2010, there was a meta-analysis study done on genome-wide lab data for “personality in 10 discovery samples (17,375 adults) and 5 in silicone replication samples (3,292 adults),” (Moor). All people were from European ancestry. Personality was scored for neuroticism (negative emotions), extraversion (positive emotions), openness to experience, agreeableness, and contentiousness. The scoring was all based on the NEO Five-Factor Inventory. “The NEO Five-Factor Inventory-3 (NEO-FFI-3), is the updated version of the NEO-FFI — a 60-item version of the NEO-PI-3. It provides a quick, reliable, and accurate measure of the five domains of personality and is particularly useful when time is limited and when global information on personality is needed”(NEO).

The results were as following:

 “ genome-wide significance to Openness to Experience near the RASA1 gene on 5q14.3 (rs1477268 and rs 2032794, p=2.8*10-8) and for Contentiousness in the brain-expressed KATNAL2 gene on 18q21.1 (rs2576037, P=4.9*10-8). We further conducted a gene-based test that confirmed the association of KATNAL2 to contentiousness. In silico replication did not, however, show significant associations of the top SNPs of Openness and Contentiousness, although the direction of the effect of the KATNAL2 SNP on Contentiousness was consistent in all replication samples,” (Moor).

The data from this study shows that there is a genome-wide significance relating to the RASA1 and KATNAL2 gene to 2 domains of personality. Further research was done on the KATNAL2 gene, associated with the personality domain of contentiousness The effect of the KATNAL2 SNP (single nucleotide polymorphism) showed to be consistent.

Single nucleotide polymorphism: .“Single nucleotide polymorphisms (SNPs) are a type of polymorphism involving variation of a single base pair” (Si Nu Po).

Another study was done on Norwegian twins to estimate how much impact genetics have on our personalities. For this study, scientists used the NEO-PI-R model of the NEO Five-Factor Inventory and the Satisfaction With Life Scale (SWLS).“The Satisfaction with Life Scale was developed to assess satisfaction with people’s lives as a whole. The scale does not assess satisfaction with specific life domains, such as health or finances, but allows subjects to integrate and weigh these domains in whatever way they choose” (Sat). Regression analyses and biometric modeling were used to determine influences on personality traits and where they came from, whether it be genetics or environmental. The results showed that Extraversion and Neuroticism emotions explained 24% of the variance in life satisfaction and facets explained 32%. Out of these facets, four were examined closer to the study. “Anxiety and depression in the Neuroticism domain, and activity and positive emotions within extraversion. Heritability of life satisfaction was 0.31 (0.22–0.40), of which 65% was explained by personality-related genetic influences” (Røysamb). 

In conclusion, though we have control over who we become, some parts of our identity were predetermined at birth. Through research and experimenting, scientists can give us a deeper understanding of this new, unknown topic. The meta-analysis study proved that there was a difference in the KATNAL2 gene when it comes to levels of Contentiousness and in the RASA1 gene with levels of Openness. The twin study showed that 65% of the heritability of life satisfaction came from genetic influences on personality. These two studies came to a similar conclusion; personality is affected by genetics.

References:

Røysamb, Espen, et al. “Genetics, Personality and Wellbeing. A Twin Study of Traits, Facets and Life Satisfaction.” Nature News, Nature Publishing Group, 17 Aug. 2018, http://www.nature.com/articles/s41598-018-29881-x.

Moor, M H M de, et al. “Meta-Analysis of Genome-Wide Association Studies for Personality.” Nature News, Nature Publishing Group, 21 Dec. 2010, http://www.nature.com/articles/mp2010128.

Jaime Derringer, Robert F. Krueger. “Predicting Sensation Seeking From Dopamine Genes: A Candidate-System Approach – Jaime Derringer, Robert F. Krueger, Danielle M. Dick, Scott Saccone, Richard A. Grucza, Arpana Agrawal, Peng Lin, Laura Almasy, Howard J. Edenberg, Tatiana Foroud, John I. Nurnberger, Victor M. Hesselbrock, John R. Kramer, Samuel Kuperman, Bernice Porjesz, Marc A. Schuckit, Laura J. Bierut, , 2010.” SAGE Journals, journals.sagepub.com/doi/10.1177/0956797610380699.

Krueger, Robert F, et al. “The Heritability of Personality Is Not Always 50%: Gene-Environment Interactions and Correlations between Personality and Parenting.” Journal of Personality, U.S. National Library of Medicine, Dec. 2008, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2593100/.

“NEO Five-Factor Inventory – 3.” SIGMA Assessment Systems, 20 Dec. 2018, http://www.sigmaassessmentsystems.com/assessments/neo-five-factor-inventory-3/.

“Single Nucleotide Polymorphisms (SNPs).” Genome.gov, http://www.genome.gov/genetics-glossary/Single-Nucleotide-Polymorphisms.
“Satisfaction with Life Scale.” Satisfaction with Life Scale | Positive Psychology Center, ppc.sas.upenn.edu/resources/questionnaires-researchers/satisfaction-life-scale#:~:text=The%20Satisfaction%20with%20Life%20Scale,in%20whatever%20way%20they%20choose.

By Sai Datla

Sai Datla is a freshman at Westford Academy in Westford, Massachusetts. She is interested in the field of psychology and human life sciences.

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