Uncovering the complex genetics of human temperament

Area of Science:

• Neuroscience
• Behavioral Genetics
• Genomics

Background:

• Human temperament shares molecular mechanisms with animal associative conditioning.
• Previous genome-wide association studies (GWAS) have not identified these genetic pathways in humans.

Purpose of the Study:

• To uncover complex genotypic-phenotypic networks and environmental interactions related to human temperament using a machine learning GWAS approach.
• To identify specific gene sets and pathways associated with distinct temperament profiles.

Main Methods:

• Employed a data-driven machine learning method for genome-wide association studies (GWAS).
• Analyzed a discovery sample of 2149 healthy Finns, identifying single-nucleotide polymorphism (SNP) sets and temperament clusters.
• Validated findings in Korean and German samples.

Main Results:

• Identified 51 SNP sets associated with temperament, implicating 736 gene loci enriched in associative conditioning pathways (ERK, PI3K, PKC).
• Found that 74% of identified genes were specific to particular temperament profiles.
• Replicated SNP set findings in Korean (90%) and German (89%) samples, explaining substantial heritability (37-53%).

Conclusions:

• Human temperament is significantly influenced by over 700 genes modulating associative conditioning via molecular processes for synaptic plasticity and long-term memory.
• Environmental factors have small but significant effects on temperament.
• The identified genetic architecture of temperament is conserved across diverse cultures and environments.