Nature vs. Nurture in Genomics: Why Both Are Important

Many factors affect how genes express themselves. Until now, this blog has exclusively discussed how understanding specific variations in an individual genome allow us to determine impact on health. But this is only half the story. Age and environment are an equally important part of the equation. Epigenetics, in part, studies how external factors affect how our genes are expressed without changing the actual DNA sequence. As it turns out, the influence of genes isn’t set in stone, but by cataloguing variants and considering them in the context of external factors, better clinical decisions can be made.

DNA Helix
Image courtesy of Victor Habbick via freedigitalphotos.net

In a study of thousands of twins, researchers have confirmed that genetic variation accounts for 48% of differences between individuals in early childhood, but that increases to 78% by adolescence. Age is a factor, while not environmental, that affects gene expression. For example, genetic factors regulating body weight change as we age. Epigenetics in part studies these changes, and the mechanisms that affect gene expression. It’s not yet fully understood exactly which elements in an environment cause genes to switch “on” or “off”, which is why more research is needed. High-end genomic analysis and access to Next-Generation Sequencing (NGS) technology are baseline requirements for an organization in order to do a proper study.  There have also been examples of an environmental change being an effective intervention for a genetic disease.

Phenylketonuria is a genetic disease that causes a defect in the enzyme that metabolizes the protein phenylalanine. This leads to a toxic buildup of this protein, affecting brain development. Completely removing this protein from the patient’s diet was found to be the most effective treatment. This demonstrates that a simple change in environment can be a valid treatment for a genetic disorder. More complex diseases, like those influenced by multiple genes, will require more complex interventions. But this goes to show that focusing solely on genetic variation gives an incomplete picture.

Studying variations in the genome has lead to a much greater understanding of how the genome impacts health. How environmental factors affect gene expression requires more study, but will only increase clinical effectiveness. New Amsterdam Genomics understands the importance of nature and nurture, they are two sides of the same coin. Appreciation of both is essential in realizing the full potential of genomics in a medical setting.

-Josh

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