Last year was the 50th anniversary of the famous discovery of the structure of DNA by Watson and Crick in Cambridge. Since that seminal finding, progress has been exponential in understanding our fundamental genetic makeup, how our genetic code underlies our development from a fertilised egg cell to a complex human being, and what goes wrong in disorders as diverse as cancer, mental illness and obesity.
We can't afford to ignore this inevitable and rapidly increasing progress in understanding our fundamental makeup and the corresponding social and economic opportunities and challenges. We can't go back in time.
And certainly when it comes to our health, let's not harbour any distorted views of “the good old days”. Life expectancy, even for the well off in England in 1750 was only 36, up to 45 in 1850.
Over the past 100 years (1900–2000), the average life expectancy in Australia has increased from 55 to 77 for males and 58 to 82 for females, and is still increasing. Does anyone want to return to the misery of the plagues of infectious disease, polio, early heart disease and septicaemia?
What has been happening in the biological sciences in the past few years?
Human Genome Project
Your genome, or your DNA, is your genetic blueprint, the information you inherited from your parents. It is composed of four simple chemicals – guanosine, adenosine, thymidine and cytosine - abbreviated G, A, T and C, arranged like beads on a string. Each of us has approximately 3 billion of these G's, A's, T's and C's linked together in extremely long strings. The order of these beads on a string is your DNA sequence.
As a single gene is only a few thousand G, A, T, C's long, you can imagine that finding that single gene out of the 3 billion G, A, T, C's has been more difficult than finding the proverbial needle in a haystack.
It was therefore no surprise that when President Clinton and Prime Minister Blair announced the first draft of the complete human genome sequence in 2000, with great fanfare on both sides of the Atlantic, it was hailed as the pinnacle of 50 years of scientific endeavour.
Over those 50 years we have witnessed an exponential increase in our understanding of genes and the human genome. From 1953 and the structure of DNA, through the late 1970s and development of gene cloning techniques, to 2001 and the complete human genome sequence, to today where several thousand gene sequences are entering the international databases every day. The Genome Consortium churns out over 1,000 G, A, T, C's of sequence every second.
What can we do with this previously undreamt of database?
For scientists the benefits are immediate – new insights into every field of biology. But the benefits will extend far beyond the research community to impact virtually every aspect of our life, but especially medicine and health care.
Most of the major diseases that challenge our community - such as heart disease, arthritis, diabetes, cancer, mental illness - all involve several genes, and environmental factors as well. We already know much about many of these environmental factors, such as smoking in cancer and heart disease and exercise and diet in diabetes and obesity. But the genetic factors underlying these complex, so called multifactorial diseases, have been hard to find.
How will the human genome sequence help?
For a start, it has changed the way we do science. Previously, rigorous research was hypothesis-based. For example, if there was evidence that a certain growth factor stimulated the growth of breast cells, I might hypothesise that a mutation causing overproduction of this factor might cause breast cancer and I would carry out experiments to prove or disprove the hypothesis. With the availability of the human genome database, it is now possible to spot gene sequences from each of the approximately 50,000 human genes onto a small silicon chip the size of my thumbnail.
This is an edited extract of an address to the National Press Club on July 21, 2004.