Modern genetics may be promising to revolutionise medicine, and even change what it means to be human, but the origins of the science stem from a humble origin - peas.

In the 1860s, the Moravian monk Gregor Mendel pioneered the study of inheritance. He cultivated nearly 30,000 pea plants, carefully analysing seed and plant characteristics.

By following certain traits through the generations, he realised that some traits appeared to be dominant while others would be recessive and fail to show when certain pea plants where crossed.

Mendel's work was extraordinary, but it was many decades before his research received the recognition it deserved.

DNA described

In 1953, James Watson and Francis Crick famously described the structure of DNA, the molecule that carries the genetic code. Theirs was undoubtedly a landmark achievement, but it could not have happened without the help of others like Rosalind Franklin who obtained sharp X-ray diffraction photographs of the molecule.

Now, the first draft of the entire sequence of human DNA is expected. But rather than being the end of the history of genetics, it is the start of a much greater endeavour which will revolutionise medicine and transform the way we think about ourselves.

A genetics timeline

• 1869 - The chemical material DNA is discovered in cells.

• 1909 - The term "gene" is first used and the chemical composition of DNA is found.

• 1920 - Chromosomes are proposed as the mechanism by which inherited characteristics are passed on.

• 1944 - DNA is first connected to the inheritance of traits.

• 1951 - The first sharp X-ray diffraction photographs of DNA are obtained.

• 1953 - Crick and Watson describe the structure of DNA.

• 1956 - DNA is made artificially.

• 1966 - DNA is found to be present not only in chromosomes but also in the mitochondria.

• 1969 - The first single gene is isolated.

• 1970 - The first artificial gene is made.

• 1973 - Genetic engineering begins with the ability to insert genetic material.

• 1977 - DNA from a virus is fully decoded for the first time.

• 1976 - An artificial gene is inserted into a bacterium and, for the first time, works normally.

• 1978 - Bacteria are engineered to produce insulin.

• 1981 - A gene is transferred from one animal species to another.

• 1983 - The first artificial chromosome.

• 1984 - Realisation that some, non-functioning DNA is different in each individual - genetic fingerprinting is born.

• 1988 - The Human Genome Organisation aims to map the complete sequence of DNA.

• 1990 - The first human gene experiment takes place to try to treat a four-year-old girl.

• 1993 - Mice are cured of cystic fibrosis as a result of gene therapy.

• 1996 - After six years of work, the brewer's yeast genome is decoded, the most complex organism so far.

• 1998 - The first multi-celled animal has its genome decoded - a worm called C. elegans.

• 2000 - The first draft of the human genome announced.

• 2001 - The first draft of the human genome published.

By BBC News Online's Dr Damian Carrington