Prof Michael Akam gave a fascinating talk on Genomes and how genetics relate to the make up of living organisms. His thesis investigating how a fruitfly develops the way it does led him into a distinguished career as a Professor at Cambridge on the leading edge of genetics.

Major breakthroughs have taken place in the understanding of DNA and how genes are unique sequences that define the characteristics of living bodies.

Because of the vast number of genes and possible combinations understanding how they related to one another and how reproduction of species entirely depends on these relationships was painfully slow in the beginning. But with the arrival of technology the understanding and processing became much quicker and more effective. So now we have a very good understanding of what genes affect what features and a map of the whole human genome.

Michael took us through the relationships of DNA and Genes in a step by step presentation. The logic of each step easily understood. However, his skill in doing this masked the fact that at the end none of us were about to get a degree in the subject. This presentation on genomes used the genome as a remarkable record of both our individual ancestry and our much deeper evolutionary history. A genome is essentially the complete set of genetic instructions contained in our cells. In humans, it consists of 46 chromosomes, arranged in 23 pairs. One chromosome of each pair comes from our mother and the other from our father. In this sense, each of us is a unique genetic combination of our parents.

The relationship is not quite as simple as receiving an equal “half” of each parent’s characteristics, however. The chromosomes passed to us are shuffled through reproduction, so the particular combination we inherit is different from that received by our brothers and sisters. Our genome therefore contains an extraordinary mixture of genetic information inherited through many generations. It also interacts continuously with our environment and with the complicated processes by which cells develop, so our DNA is not simply a blueprint that mechanically determines what we become.

Michael’s wider interest was in understanding how genomes can produce the enormous diversity of living creatures. One of the striking discoveries of modern genomics is that animals which look radically different can possess remarkably similar genes.A Cape rock shrew shares a much closer relationship with an African elephant than a regular shrew. Genes involved in controlling development, including the Hox genes with which Michael worked extensively, are found across widely separated groups of animals. 

This leads naturally to our relationship with chimpanzees. Humans and chimpanzees did not descend one from the other. Rather, humans and modern chimpanzees share a common ancestral population that lived millions of years ago. Since that population separated into different evolutionary lineages, each lineage has accumulated genetic changes. Consequently, much of our DNA is still recognisably related to that of chimpanzees, while the differences that have accumulated help explain the profound differences in anatomy, development and behaviour.

Michael’s important point is that the interesting question is not simply how many genes humans and chimpanzees share. Many animals share genes that perform fundamental functions. The more difficult question is when, where and how those genes are switched on and off. Changes in regulatory regions of DNA can alter development without necessarily changing the proteins produced by the genes themselves. Michael emphasised this regulatory complexity in explaining how similar genetic machinery can produce very different forms. 

Thus, our genome connects us simultaneously to our parents, to our ancestors and to every species with which we share evolutionary history. It is both a personal inheritance and a record of deep biological ancestry.

An excellent presentation making a complex subject sound simple. Thank you Michael.