CNCR Researchers publish in Science

04 June 2013

A worldwide consortium of medical researchers and social scientists found that tiny differences across a person’s genetic sequences are associated with the educational level.

CNCR researchers publish in Science: New study discovers novel genetic associations with educational attainment

The Social Science Genetic Association Consortium conducted this study. The Consortium includes Danielle Posthuma, Thais Rizzi and Christiaan de Leeuw from the Neuroscience Campus Amsterdam (NCA) and the Center for Neurogenomics and Cognitive Research (CNCR), at the VU University and VU Medical Centre Amsterdam.

The study was exceptional in terms of its sample size. It included genetic information of more than 125,000 people, looking specifically at a type of genetic variation called single nucleotide polymorphisms (SNPs). It was investigated whether any of these small genetic differences across people were associated with the number of years of schooling and whether or not a person had a college degree.

The study identified a number of SNPs that are robustly associated with educational attainment. No individual SNP accounted for more than 0.02% of the variation in years of schooling. Yet, all SNPs combined could eventually explain up to 20% of variation if even larger samples would be available for analyses.

Educational attainment – a complex trait

Posthuma explains that educational attainment is – like many other human traits – a so-called complex trait, which is influenced by hundreds of genetic and environmental influences, each of small effect. “Although our findings represent only a very small piece of a very large puzzle, involving many other genetic and environmental factors, it does have a number of significant implications‚.

These small genetic changes, though they have little effect alone, may point to the tip of the iceberg. Discovering them helps us to identify which genes are involved, leading us to study the function of these genes in much greater detail, which subsequently may lead to insights into biological pathways underlying human behaviour.

The study may also help to understand why some people are more susceptible to early cognitive decline than others.

“We are interested in understanding differences between people in cognitive dysfunction because that may lead to a better understanding of why some people cognitively age better than others or why some people have a better memory performance. This might be important for understanding genetic susceptibility for age-related cognitive decline, such as associated with Alzheimer’s Disease or Parkinson’s Disorder‚ Posthuma said.

In addition, the study had a sample size about 10 times larger than any other study investigating social-scientific outcomes. Researchers of the Erasmus University Rotterdam and the Erasmus MC led the study.

GWAS studies

“For GWAS studies, large numbers are crucial. Especially when effect sizes are so tiny. By increasing the number of individuals, we can move towards a better understanding of the true effects of genetic variants on behavioural traits, ‚ Posthuma said.

The study, “GWAS of 126,559 individuals identifies genetic variants associated with educational attainment‚, was published online on 30 May 2013 in ScienceXpress