Our understanding of the function of the Human DNA, known as the Human Genome, is steadily progressing. As a result the possibilities for testing and screening for genes involved in inherited diseases or susceptibility to diseases have increased spectacularly. In addition, modulators of gene expression - other genes, non-coding DNA sequences, proteins involved in the three dimensional organization of DNA (Epigenetic factors) and acquired but heritable modifications of DNA - are being identified. This has lead to the surprising realization that even environmental factors, such as food components can modify the DNA function quite dramatically. As a result, most simple tests, as done today, will have to be complemented with tests allowing more precise predictions of the risks, of the progression and of the clinical characteristics of diseases.

High throughput DNA sequencing has also opened a series of new approaches for the identification of individual characteristics, which may be relevant for determining risks to develop diseases or to show variation in the rate at which we metabolize drugs. Indeed, our DNA contains quite some individual variation in its composition. Testing for predispositions to develop particular diseases and pharmacogenetic testing have indeed great futures, although much research will still be needed before these approaches can be routinely implemented in practice. The 1000 Euros genome sequence is indeed not for tomorrow.

Analysis of individual variants also allows the identification of biological traces collected at crime scenes with great accuracy. Application of this knowledge in forensic cases and in studies of biological descent has become routine. It is clear that we are only at the beginning of our understanding of what the function is of all the DNA fragments, but already today many examples exist of what DNA analysis can contribute in medicine and in many other fields.