Neurogenomics, the field that investigates the genetic basis of differences in brain structure and function, is constantly developing but faces challenges that require attention. (Mitchell, 2018)
Twin and family studies have shown that most behavioral and cognitive phenotypes, including personality traits, intelligence, memory, and even the occurrence of specific behaviors such as educational attainment and physical violence, are moderately heritable. The same is true for psychiatric disorders. (Mitchell, 2018)
Neuroimaging has revealed that many structural and functional brain parameters are also heritable. The promise of neurogenomics is to identify genetic variants that contribute to these differences, which may lead to a deeper understanding of the molecular and neural mechanisms underlying cognitive and behavioral functions. (Mitchell, 2018)
However, the field has been plagued by methodological problems, especially in candidate gene association studies. These studies analyze the frequency of genetic variants in specific genes in people with different levels of brain phenotype. (Mitchell, 2018)
While promising in principle, these studies have been plagued by problems such as small sample sizes, lack of correction for multiple testing, poorly defined hypotheses, and publication bias. The neurogenomics community needs to learn from past mistakes and adopt more rigorous standards to ensure that results are accurate and reliable. (Mitchell, 2018)
The use of genome-wide association studies (GWAS) represents a promising advance. GWAS allow researchers to look for frequency differences in thousands of SNPs across the genome, requiring larger sample sizes and rigorous statistical methods. (Mitchell, 2018)
Although still in their early stages, GWAS have already yielded significant results, identifying common variants that contribute to variation in hippocampal volume, for example. These studies also indicate that much of the variation in brain structure and function may be due to rare genetic variants that are not captured by GWAS. (Mitchell, 2018)
In short, neurogenomics has tremendous potential to unlock the mysteries of the human mind, but the scientific community needs to focus on rigorous, well-defined methods to ensure that research advances in a robust and reliable manner. (Mitchell, 2018)
Reference:
Mitchell, K. J. (2018). Neurogenomics—towards a more rigorous science. European Journal of Neuroscience, 47(1), 109–114. https://doi.org/10.1111/ejn.13801
