The nature vs nurture debate has been a topic of interest in science for many, many years. It is still unknown to what extent hereditary (nature) and environmental (nurture) factors affect human traits. These two sets of factors have traditionally been considered largely independent of one another. Recently however, more and more studies are focusing on the intermixed effect of nature and nurture.
The recent deCODE paper published in the journal Science is one such study. Kong et al. studied genetic nurturing effects on educational attainment (highest degree of an education one has completed). They showed how parental and sibling genetic information can shape the environment that consequently affects the child. The study was performed in an Icelandic population using parent-offspring data which enabled the researchers to look at the both transmitted and non-transmitted maternal and paternal alleles. The genetic material that has not been passed from the parents to the child had an average effect size of 34.2% the effect of transmitted alleles.
When performing genome-wide association studies (GWAS) one is looking at the association between the transmitted alleles in a child and the trait. The results of the GWAS have been interpreted as the direct effects. However, the existence of the nurturing effects as shown by this study is highlighting how an indirect effect (genetic nurturing) is amplfying GWAS results.
More attention should be given to investigating the effect of the non-transmitted alleles. Knowing that many neuropsychiatric disorders run in families, and that parental behaviour is having an important environmental effect on children, it may be worth looking into the effects of genetic nurturing on neurodevelopmental disorders.
More information about the study discussed here can be found at the following link: http://science.sciencemag.org/content/359/6374/424