(as originally appeared on MichaelRansomBooks.com, August 18 2015)
The progress in the last decade leading to the sequencing of all 3.2 billion letters (i.e., nucleotides) of the human genome has unleashed a bewildering array of possibilities and unexpected avenues for biomedical research. The speed with which the technologies for sequencing DNA have evolved is dazzling. Ten years ago, the first human genome map was constructed at a cost of 3 billion dollars and 15 years and revealed to the world by President Bill Clinton and Prime Minister Tony Blair. Today a human genome can be generated in a week and costs approximately $2,500 to complete. Exciting companies like “23 and Me” have begun to flourish as the general public becomes increasingly interested in understanding their personal genetic code. Today, almost 100,000 human whole genomes have been sequenced, and on a recent trip to China I learned that a “million genomes project” is now on the horizon. In the not too distant future, the vast majority of the industrialized world will have had their genomes sequenced from birth and onward.
Mutations in just one out of the 3.2 billion nucleotides in each human cell’s DNA can lead to devastating diseases, or even death. Other alterations (so-called polymorphisms) at multiple points along immense stretches of our DNA can have less pronounced effects, which are correspondingly less well understood. While an appreciably large body of research has determined the effects of such genetic alterations affecting human biology (genes linked to cancer, sickle cell anemia, Crohn’s disease, etc.), there remains a relative dearth of information as to the extent such DNA variations play in human behavior.
Nonetheless, as DNA analysis tools have evolved, a growing amount of evidence in hundreds of articles published in the last few years suggests that variations in our DNA may indeed be linked to many behavioral tendencies and psychological disorders. A study reported a decade ago in Science had already suggested that the likelihood of violent behavior was higher in people possessing a variant in one gene versus those who did not [1]. Newer studies are continually emerging to support this notion [2-5]. Recent reviews of the growing scientific literature highlight the possibility of a here-to-fore unappreciated contribution of genetics to violence [6]. It is hoped that today’s more advanced “next generation sequencing” technologies in genetics will help us understand more complex variation, across all human genes, that are linked to different types of violent behavior. The application of such (as yet nonexistent) technologies in the field of behavioral forensics is, in fact, the scientific premise behind The Ripper Gene.
“Does violence beget violence?” is a classic question in the nature versus nurture debate. The answer appears to be yes, at least in some cases, but that doesn’t help us deconvolute the contributions of environment versus genetics. Most scientists believe that it’s a combination of the two, but it’s possible that certain genetic alterations can play a stronger role in predicting violent behavior than others. A recent comprehensive genetic study of more than 18,000 twins suggests that the effect of environment may be overestimated [7]. If that’s the case, then DNA may predispose individuals to anti-social behavior, making for an interesting interpretation of what is meant by “human free will’, one of the main themes in this novel.
Religion and science will always be at odds, because science cannot make use of faith to determine the validity of its hypotheses, and faith transcends the laws of the observable world measurable by the scientific method. The extent to which the molecular blueprint of life—the human genome—dictates our choices and behavior in the context of spirituality and free will seems impossible to decipher. Is the near-universal sense of human conscience hardwired into our DNA, but incorrectly wired in the small fraction of those most violent offenders? And if so, what does that mean for the roles of environment, spirituality and genetics in the determination of our fates? As with any good hypothesis, a good question leads to more questions than answers… and so it is with the sequencing of the human genome and these initial attempts to determine the extent of its role in establishing not what we are, but who we are. The new era of beginning to understand this one aspect of our humanity—our human genome—is most certainly only a new rephrasing, rather than an ending, to the long-time question of “Nature versus Nurture” in the context of human behavior.
REFERENCES
1) Stokstad E. Violent effects of abuse tied to gene. Science, 297:752, 2002.
2) Huang YY, Cate SP, Battistuzzi C, et al. An association between a functional polymorphism in the monoamine oxidase a gene promoter, impulsive traits and early abuse experiences. Neuropsychopharmacology. 29:1498-1505, 2004.
3) Nilsson KW, Sjoberg RL, Damberg M, Leppert J, Ohrvik J, Alm PO, Lindstrom L, Oreland L. Role of monoamine oxidase A genotype and psychosocial factors in male adolescent criminal activity. Biol Psychiatry. 59:121-127, 2006.
4) Bhakta SG, Zhang JP, Malhotra AK. The COMT Met158 allele and violence in schizophrenia: a meta-analysis. Schizophr Res. 140(1-3):192-7, 2012.
5) Ferguson, CJ. Genetic contributions to antisocial personality and behavior: a meta-analytic review from an evolutionary perspective. J Soc Psychol. 150:160-80, 2010.
6) Tuvblad C, Baker LA. Human aggression across the lifespan: genetic propensities and environmental moderators. Adv Genet. 75:171-214, 2011.
7) Forsman M, Långström N. Child maltreatment and adult violent offending: population-based twin study addressing the 'cycle of violence' hypothesis. Psychol Med. 42:1977-83. 2012