Cross-posted with Biopolitical Times on March 8th, 2016.
We have become accustomed to ascribing individualistic agency to our genes. We speak of gene x doing thing y. However, our biology is not a collection of independent actors, but a highly interdependent ecosystem. And every now and then a story comes along that reminds us just how foolish we are to forget that.
In what is being called the first of its kind in the UK, the birth of a pair of genetically identical twins provides a striking case in point. Despite having split from the same embryo, one of the girls has brown eyes and darker skin, while the other girl has blue eyes and fairer skin. Other couples have defied the odds with the birth of two sets of twins with different skin and eye colors, but the notion of identical twins looking markedly different is much more unusual.
Studies have shown that identical twins growing up in the same household with largely the same opportunities and experiences can still develop quite different personalities and skills. This has largely been attributed to the growth of new neurons in the brain. But the rest of our bodies are also far from static.
Massive studies of identical twins have discovered that hundreds of genes can end up contributing to just 1% of the heritability of a disease or trait; moreover, epigenetics – the expression of genes – can profoundly alter phenotypic outcomes.
Such visual divergence of identical twins is very rare, but even rare findings have important consequences. As I tweeted last week, the finding “sure throws a wrench in that whole genetic determinism thing…!” And as Dorothy Roberts (Professor of Law and Sociology at the University of Pennsylvania as well as an Advisory Board member of the Center for Genetics and Society) responded, this case particularly complicates the notion of biological race:
“Black” and “white” identical twins also throws a monkey wrench in that whole biological races thing. https://t.co/HpCvqkpnWJ
— Dorothy Roberts (@DorothyERoberts) March 1, 2016
Recognizing the multiplicities of our bodies and identities matters. For one thing, we can refute those who try to justify inequality on the basis of (purported) genetic differences, and make the critical point that, for example:Genes Don’t Cause Racial – Health Disparities, Society Does. And that, “There is no inherent reason why children from low-income families cannot succeed as much as those from affluent homes.”
None of this is to deny the role of genetics, which is obviously a necessary and critical component to us all. However, as long as the myths of “individualistic” genes and genetic determinism continue to circulate wildly, it seems worthwhile to take the opportunity to remember that DNA is neither static nor prescriptive. Just as every locust is a genetic grasshopper facing a phase change brought on by hard times, so too are humans radically impacted by their environments. No amount of physical tinkering will ever erase the also necessary and infinitely messier importance of the outside world.