About a year ago I posted the first article in this series, asking whether recent advances in genomics made any difference to the Judeo-Christian notion of humanity being made in the 'image of God'. That article focused on DNA sequencing data from our closest relatives. This article will focus on the issue of genetic determinism.
Theologians have spent many centuries mining the rich vein of the 'image of God' metaphor. Central to the idea is humanity with spiritual capabilities and responsibilities, equipped for moral decision-making and a relationally rich life in community. Historically, the idea has contributed to the conviction that each human individual has an absolute value, independent of their ethnicity, educational level, health status or income.
Do recent advances in genomics threaten or support such a view of humankind, or are they just neutral? Irrespective of one's belief in God, or not, this is of more than passing interest. Imagine the poor person wrestling for years with the great questions of life and finally deciding to become an atheist, only to then be informed that a cognitive bias derived from his particular set of genetic variants made that decision pretty much inevitable anyway. Such news might be equally unsettling for the person who had just struggled to faith following years of agnosticism. Our deepest human feelings are closely connected with the idea that we choose our own path through life.
The flourishing of genomics in the early part of the 21st century has certainly conveyed the message to many that one's destiny is written into one's genome. Whereas scientists are generally scrupulously careful not to give the impression that there is any such entity as a "gene for" some human trait, by the time the latest discovery appears in the media, such caution is often thrown to the winds. The past year has seen the trumpeting of a "gene for happiness," a "kindness gene" and a "believer gene." It is not even a question of education, but "genes are to decide" if you are a "caring person." Genetic testing websites assure us that "your genes are a road-map to better health," and we all know that road-maps are fixed. Small wonder that there is a creeping genetic fatalism around that subverts the idea of personal responsibility.
Fatalism in itself impacts on human behavior. Studies have shown that subjects exposed to the writings of authority figures doubting free-will are then more likely to cheat. Conversely, workers convinced of the reality of free-will are rated higher in the work-place than those whose beliefs tend more towards determinism.
The reality is that recent genetics research has continued to move steadily away from any notion of genetic fatalism, highlighting the sheer complexity of the genome, and providing some fascinating examples of the ways in which our choices impact upon our own genomes. There is no gene "for" any complex human trait because in fact genes encode proteins or other types of information-containing molecules, and thousands of genes collaborate together during human development in interaction with the environment to generate the unique human individual that each person represents. Those requiring an introduction for the non-specialist are referred to "The Language of Genetics."
Epigenetics adds further layers of variation and complexity. This refers to the chemical modifications of the DNA that cause genes to be switched on or off. It is such epigenetic modifications that generate the 220 specialized tissues of our bodies. Such acquired changes can even be inherited across several generations, certainly in plants and animals, and maybe in humans as well. In choosing to smoke, drink in excess, or take drugs, we also choose to modify our genomes.
So it turns out that even identical twins are not really genetically identical, developing different profiles of epigenetic modification as they go through life. This no doubt contributes to the otherwise surprising result that the age of death of identical twins, who share identical genomes, is comparable with that observed in non-identical twins, whose genomes are as different from each other as any two sibs. In one study of 184 pairs of twins in Spain, the difference in the age of death between the identical twin pairs was seven years on average, but such averages hide the fact that the age differences ranged from a couple of weeks to eighteen years. In the case of the non-identical twins, the difference in age at time of death was nine years, and the range was three to nineteen years. So there was really not that much in it.
What would happen if there was a genetic marker that identified nearly everyone in prison, marking them out as genetically distinct from half the world's population? What would that do to our ideas about genetic fatalism and convictions about moral responsibility? As it happens that marker already exists. Out of 131 countries worldwide, an average of 96 percent of the prisoners are male and, in this case, no complicated genetic studies are needed to know that the genetic marker that identifies this population is the Y chromosome. So universal is the correlation between the Y chromosome and criminality that we can safely say that no other genetic correlation will ever be found between a variant genome and criminality that surpasses this one. And yet we still hold nearly all males responsible for their criminal actions and put them in jail as soon as they're convicted. Furthermore, we note that most people who possess a Y chromosome go through life without committing a crime. So having a Y chromosome, with its unique set of genes, does not "determine" human criminality, although clearly we cannot go to the opposite extreme and say that it is completely irrelevant for patterns of human behavior.
The point in citing such examples is not to suggest that our genomes have nothing to do with our lives. They certainly do, not least in their significant contributions to our personality differences. The point rather is that the latest results in genetics provide no grounds for fatalism, instead highlighting the richness and diversity of the human population, and our own moral responsibilities, including the challenge to be good stewards of our genomes.
An argument for the existence of God this is not. But for those of us whose world-view is shaped by the conviction that we humanity are made in God's image, it is good to know that the latest genetics is consistent with such a perspective.