In some ways it all started with mice. I’m a typical reductionist biochemist who mashes things up to see how they work at the molecular level. But when I shifted my research career to molecular immunology whilst working at The Babraham Institute, Cambridge, UK, it became increasingly apparent during the 1990s that the mouse was the system of choice for understanding how molecules work to mediate immune responses as part of a complete system.
Genetics was and is a huge help in this enterprise. Like many other labs working in this field, we had gene “knock-out” mice (mouse colonies in which single genes have been deleted); transgenic mice, conditional knock-outs and much else besides. Phenotypes (what happened in the mouse immune system in this case) were often unpredicted and unexpected. The great lesson from such work is that genes operate within complex developmental systems in which everything is connected. Far from being a recipe or an information manual, the genome (the sum total of the genetic information in an organism) is a key contributor within a complex system of proteins, lipids and various communication molecules that together lead to the development of living organisms like mice (and us).
Whilst developmental biology was undergoing a revival alongside systems biology, the public [mis]understanding of genetics, particularly of behavioral genetics, was moving in the opposite direction. The sequencing of the human genome in the early noughties, a great triumph for genetics, was reported by the media using hubristic metaphors such as “the Holy Grail,” “the Book of Life” and “the Code of Codes.” Here at last was the recipe that would explain human identity—or so the results were communicated in some segments of the media.
The situation has not been helped by the insistence of the media to keep reporting the discovery of a gene “for” this, that, or the other—there are mean genes, gluttony genes, gangster genes, liberal genes, religious genes, and even the whimsical suggestion of a “geneticism gene” that predisposes some people to think that behavior is caused by genes…..
The phrase “it’s in his or her DNA” or in the organisation’s DNA has come into our daily language to suggest that a particular characteristic is intrinsic and probably not readily changed. The cloud computing service provider Oxygen assures us that our security is in their DNA. In commenting on its new TV drama series, the UK director-general of the BBC was recently quoted as saying that “drama is something that is in the lifeblood of this country and in the DNA of the BBC too.” The presumed implications of such language are clear: what is in the DNA must be immutable and unchangeable – somewhat missing the point that our DNA is undergoing a constant process of change and diversification.
Scientific reporting on behavioral genetics has also been misleading on occasion. As a recent news article in Nature reports: “An increasing number of studies suggest that biology can exert a significant influence on political beliefs and behaviors,” suggesting that “genes could exert a pull on attitudes concerning topics such as abortion, immigration, the death penalty and pacifism.” [Buchen, L. 2012. “Biology and Ideology: The Anatomy of Politics.” Nature, 490: 466-468]. John Hibbing, a political scientist at the University of Nebraska-Lincoln, is quoted as saying that, “…it is difficult to change someone’s mind about political issues because their reactions are rooted in their physiology.” We note the assumption of determinism. Genes and physiology are seen as something different from “us” and “our mind,” and they seem to be controlling us, so we can’t even change our mind.
Genes, Determinism and God aims to critically survey the current state-of-play with regard to the role of genes in human personhood, focusing on the relationship between genetic variation and human behavior in the context of ideas about human freedom and determinism. It is contemporary biology—more than ideological considerations—which actually subverts all kinds of popular dichotomies, be they nature/nurture, hereditary/learning or genes/environment. Developmental biology provides the key, and a considerable portion of the book is given over to explaining—for the non-specialist—how human personhood emerges from a lengthy multi-causal developmental process in which the genome is but one important molecular component amongst many.
Animals a lot simpler than humans are a help in elucidating the issues. For example, the famous little nematode worm, C. elegans (famous because it was the first organism to have its genome sequenced), is only around one millimeter in length and comprises just 959 somatic (non germ-line) cells. Yet it contains just over 20,000 protein coding genes, a number similar to that of the human genome, and undergoes a complex developmental pathway to reach adulthood. No single gene encodes any behavior in C. elegans, but there are plenty of variant genes that make a difference as to how the worm behaves, differences due to the role(s) of different forms of the same gene during development.
A theme that crops up repeatedly in Genes, Determinism and God is how variant genes are “difference makers.” Hundreds of genetic variants help to explain differences between individuals in a given population with regard to particular human traits. Traits may be as varied as personality type, educational attainment, levels of aggression, religiosity, sexuality, or level of political commitment. The aim of behavioral genetics is to assess the proportion of variation in a population that can be attributed to genetic variation, a measurement known as the “heritability” of a trait.
Molecular genetics follows up by seeking to identify which genetic variants contribute to the heritability. In practice, there are hundreds, perhaps thousands, of variants that contribute to the heritability of complex traits like intelligence, each one contributing a tiny percentage of the overall variation. This is not surprising when one remembers that thousands of genes are involved in brain development.
Aside from rare but sad cases of medical pathologies, there is nothing deterministic about genetics, but the developmental process in which genes are intimately involved does lead to predispositions to have a particular kind of personality and to behave in certain ways. Genes, Determinism and God tackles the philosophical question as to how genetic influences relate to free will. The related and thorny question as to how genetics is used in the legal system is also addressed.
What can theology possibly have to do with genetics? Quite a bit, as it turns out. A fruitful conversation can be mediated via the ancient Judeo-Christian idea of humankind made in the image of God, an idea that has been historically powerful, contributing to the shaping of moral values, political systems, medical care, education and the justification of human rights.
Thomas Metzinger has commented, in a recent edited volume entitled Neural Correlates of Consciousness: Empirical and Conceptual Questions that, “Implicit in all these new data on the genetic, evolutionary, or neurocomputational roots of conscious human existence is a radically new understanding of what it means to be human.” He goes on to claim that this emerging account of the human person is “strictly incompatible with the Christian image of man.” Genes, Determinism and God takes precisely the opposite view: never before have the findings of science regarding the human person seemed so compatible with a Christian understanding of human personhood, and never before so relevant to the bioethical challenges arising from advances in genetics.
Following some discussion of what the term “image of God” actually means in its linguistic context of the ancient Near East, the concept is then brought into discussion with genetics in five different ways:
- Via discussion of the image of God as referring to the whole person, consistent with the integrated view of personhood provided by contemporary developmental biology,
- Via the way in which the “image of God” provides a basis for the value and status of each human individual, subverting any attempt to discriminate against people based on their genetic endowment,
- Via the question as to how far we should go in controlling or changing the genome,
- Via the celebration of diversity in community which is nurtured by both genetics and theology,
- Via the way in which being made in the image of God provides a theological underpinning for notions of moral responsibility and free will.
This is a “both-and” book. Those who prefer confrontational “either-or” discourse should look elsewhere.