The knowledge of the structure and function of DNA is probably the most powerful concept in biology, standing, as it does, at the very heart of our understanding of inheritance, and co-ordination of the biochemical activity of the cell. For some scientists, the molecular approach to the science of life–with DNA as the master molecule – provides a comprehensive understanding of nature. Unsolved problems such as the nature of human consciousness or how an embryo develops will be clarified as soon as the appropriate genes are cloned – they say. Others argue that molecular genetics is only part of a far larger picture and that other theories and ideas are equally worthy of attention and further exploration.

Neo-Darwinism and the selfish gene

Neo-Darwinism, as a theory, is not as modern as it sounds. The term was first coined in 1896, and refers to the synthesis of the work of Darwin with that of Mendel. Just to recap, Darwin's observations of nature led him to propose that variation of phenotype within species occurred, and the variants that were best adapted to the environment would leave more offspring (‘the survival of the fittest’). Thus, life evolved through the generations. Mendel took one step further towards a mechanism for inheritance with his experimental discovery of genes as being discrete inheritable entities.

The discovery of the self-replication of DNA, and of gene mutations that were transmitted from cell to cell, and through the generations, provided a powerful explanation for both Darwin's and Mendel's theories at a fundamental molecular level. Genes are stretches of DNA.