The Genes Genie

It is 20 years since the Human Genome Project was completed. At the time, Francis Collins (the US leader) described it as "our own instruction book for making a human, previously known only to God". Philip Ball says this is part of misleading rhetoric only confusing the public (https://www.theguardian.com/commentisfree/2021/jun/09/human-genome-genes-genetic-code). Over my own many decades of teaching, I have also noted that the general public seem quick to believe that any human feature is 'all in the genes'. They are less ready to accept that the environment, culture and education play roles in determining what human being comes out on the 'production line'. Many people are also happy to suggest the 'undeserving poor' are responsible for their own plight, through lack of effort rather than circumstance. Ball points out that, in spite of early hopes, there has been only limited progress in gene therapy and tailoring drugs to the patient's genetic inheritance. He also rightly points out that the popular 'ancestry kits', offered by companies like 23andMe and AncestryDNA, cannot accurately tell you how much of your inheritance is 'Irish', 'Scandinavian' or 'Neanderthal'. One of the reasons for this is the 'genetic roulette' of meiosis (the form of cell division, producing eggs and sperm). Meiosis is a process that maximises genetic diversity (enabling organisms to adapt to changing environments). The 46 human chromosomes have about 8.5 million different ways of segregating themselves into the products of division (this is a random process). An individual has half their DNA from each of the maternal and paternal lines. Meiosis also involves a process called 'synapsis', where some chromosomal pairs lay across eachother. 'Crossing over' can then occur, where a section of a chromosome from the father's line is exchanged for the corresponding section of the mother's line Consequently, further enormous genetic diversity is introduced. What one gets and what one loses from the parental lines is clearly down to kismet. There are further complications. Once an individual has his/her DNA, some genes act collectively to determine factors like body height and intelligence. Environmental influences also determine which genes are switched on and which are switched off at particular times. So, although an individual may have genes, predisposing them to developing, e.g. depression, they may never develop that condition. Predicting one's chances of developing medical conditions, purely on the basis of a limited DNA analysis, is a very inaccurate process. It can sometimes cause indivuals to worry inappropriately. The public clearly need help in understanding that DNA is not simply a 'blueprint' for a human.