How do polygenic scores predict behavioural tendencies?

Polygenic scores predict behavioural tendencies by estimating an individual's genetic predisposition towards certain behaviours.

Polygenic scores, also known as polygenic risk scores, are a statistical measure that scientists use to predict an individual's genetic predisposition towards certain behaviours. They are calculated by adding up the effects of many genetic variants, each of which has a small influence on a particular trait. These scores are based on the results of genome-wide association studies (GWAS), which identify genetic variants associated with particular traits or behaviours.

The concept behind polygenic scores is rooted in the understanding that many behaviours are not determined by a single gene, but rather by the combined influence of many genes, hence the term 'polygenic'. These behaviours can range from personality traits, such as extraversion or neuroticism, to the likelihood of developing certain mental health disorders, such as depression or schizophrenia.

The predictive power of polygenic scores is not absolute. They provide a probabilistic estimate rather than a definitive prediction. This means that while individuals with higher polygenic scores for a certain trait are, on average, more likely to exhibit that trait, it does not guarantee they will. Environmental factors and individual experiences also play a crucial role in shaping behaviour.

Moreover, it's important to note that the accuracy of polygenic scores can vary depending on the trait in question and the population studied. For instance, polygenic scores derived from GWAS conducted primarily in European populations may not accurately predict behaviours in individuals of non-European descent due to differences in genetic architecture.

In conclusion, polygenic scores offer a valuable tool in behavioural genetics, providing insights into the complex interplay of genes in shaping our behaviours. However, they are not deterministic and should be interpreted with caution, considering the influence of environmental factors and the limitations of current genetic research.