The elusive associations of nucleotides with human success: evolutionary genetics in education and social policies

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Introducing the fundamental principles of evolution and genetics in the pedagogy of biology and curricula should emphasize an understanding of the basic evolutionary genetic mechanisms. These mechanisms involve a number of intervening and highly variable biological and environmental parameters that affect the inheritance and development of complex traits. This implies that an individual’s DNA sequence alone is insufficient to precisely determine what traits they would or do possess at any given time in their life course. It is not just a matter of uncoupling the genetic and environmental components of a given phenotype, but of understanding the network of causal influences and its complex genetic architecture of phenotypic components. The primary aim of this paper is to provide a general understanding of the scientific background needed by teachers and curriculum designers about the complex and often unpredictable relationships between DNA sequences and the complex traits they influence. This idea holds special importance in classrooms, because failing to integrate this perspective in the context of human genetics and evolution education reinforces essentialism about human beings, that is, the view that a person's biological, physical and intellectual abilities are fixed. Educators and students alike must avoid taking this view. Here, we aim to caution readers to be aware of the limitations of claims made on behalf of DNA-based predictive indices when applied to evaluate children for their potential for educational, financial, and social success. These indices include the classic heritability concept and, more recently, 'polygenic risk score' (PRS). The latter is especially significant because it is often recommended in clinical diagnostics, and is inferred from 'big data' consisting of millions of DNA markers known as 'genome wide association studies' (GWAS), which gives it an air of credibility. GWAS has enabled mapping of specific regions of the human genome associated with many complex polygenic traits. These individual DNA markers indicate a suggestive or real causal association, but their magnitude of influence (effect size) on complex traits is usually small; to compensate, the individual effects of markers that show association are combined into a PRS, a predictive index, which is then applied in clinical diagnostics or to estimate the magnitude of the cumulative influence of DNA markers on a quantitative trait. Behavioral scientists have extended this rationale to predict future educational achievements and financial prosperity of school children. We question the rationale behind these applications by exploring evolutionary genetic principles underlying quantitative traits, particularly the traits used to predict future social and educational achievements in children. Further, because additive effects of alleles form the basis for inferring the properties of PRS and heritability indices, they are constrained by genetic, developmental, and environmental uncertainties, and the complex architectures of correlated phenotypic traits. We assert that PRS, like heritability, is neither a static nor a deterministic property of genes for individuals or populations—it is dynamic and contextual. It can be easily modulated through socio-cultural niche construction and epigenetic reprogramming. We conclude that the application of molecular indices to predict educational and financial success of children is untenable, and should be avoided.