Just Finished Reading: Blueprint – How DNA Makes Us Who we Are by Robert Plomin (FP: 2018) [188pp]

We’ve come a long way since the Human Genome Project fully sequenced the first person. Not only is genome sequencing far faster these days it’s also a great deal cheaper too. Which is good news for those investigating the genetic factors in human behaviour, which is the author’s field of expertise.

For a LONG time now the debate has raged over the relative impact of Nature and Nurture. I remember this was a HOT topic back in my school days. Both sides have their advocates and the discussion has bled into both the Philosophical and Political domain. Talk of Free Will and Determinism abound in the debate and arguments about being ‘slaves’ to our DNA start flame wars across cyberspace. Confirming genetic inheritability of things like school attainment, obesity and sexuality are highly controversial in today’s super-charged environment (I’m looking at YOU Facebook) and the author is fully aware of this and the debates that rage throughout the genetic minefield (and mind-field!). However, this is all well and good but as more and more people have their genome sequenced and larger and larger studies are undertaken the evidence for genetic factors in much (if not all) of human behaviour is becoming unassailable. Many things that we have taken for granted as caused exclusively by environmental factors or are greatly amenable to environmental change are apparently nothing of the sort. Using LARGE studies of twins (both fraternal and identical), adopted siblings, and non-identical siblings separated in their early years it is clear that a significant percentage of human behaviour is genetically inherited. For example, whilst ‘only’ 50% of general intelligence is inherited a whopping 70% of spatial ability – the ability to navigate – is inherited from your parents (although I’m pretty good at navigating from a map my initial sense of where I am is terrible. If I need to go right I will invariably go left until I learn my mistake. I wonder which of my parents gave me that particular ‘skill’.). Interestingly stomach ulcers are 70% inherited as is Autism. Whereas height is 80% genetic and weight is, again, 70%.

If that wasn’t interesting enough the other thing which really got me thinking was the number of genes involved. I remember the amazement/horror some years ago when they supposedly found the ‘gay gene’. Reactions varied (naturally) with some hailing it as a victory that gay people are simply following their genetic disposition so it’s as natural as the day is long and not, as some maintained, an aberration whilst others celebrated the idea that they could now pick ‘straight’ in vitro embryos for re-implantation. Unfortunately for those on the side of human genome manipulation things have been confirmed as rather more complex than that. It had long been assumed that, at most, a small handful of genes are in control of various aspects of our being. So modification of these genes would produce any desired result – children with a higher IQ or an immunity to X. Not so fast. It appears that visible effects of single genes are tiny and had not, until recently, been picked up because the pool being tested was far too small. With bigger and deeper pools we discovered that attributes such as intelligence are influenced by 10’s and sometimes 100’s of genes. Modifying that many without the law of unintended consequences seriously smacking you in the face (if you’re lucky!) is decades away if possible at all. Likewise picking the ‘best’ embryo in vitro might be a juggling act of increased IQ, reduced chance of heart disease but increased chance of baldness and autism. Whichever way you cut it the ‘perfection’ of humanity through genetics might be a busted flush if the data keeps moving in the direction it seems to be.

Of course there are many, many upsides to the information now building up. Early warning of physical and behavioural issues that can be addressed early enough to mitigate or prevent later catastrophic results plus individually tailored medication or educational programmes. Knowing that a child is genetically predisposed to have reading difficulties (for example) allows for extra resources being applied and removes any stigma of being labelled as ‘slow’ or being called ‘stupid’ by others. It’s still very much a tangled field of endeavour but our knowledge is increasing and the benefits could be great indeed. Told by an expert in his field who is obviously excited by what has been uncovered so far as well as the road ahead this is an interesting read that shouldn’t tax anyone with a reasonable scientific background. Plus there are LOTS of notes in the back if you want to dig deeper. Recommended.