The first complete human genome sequence was obtained in 2003, thanks to the efforts of hundreds of researchers from around the whole world for 12 years and at a cost of about 3 billion USD. Only 15 years later and due to remarkable progress in sequencing technologies (next-generation sequencing-NGS), time and costs have been significantly reduced and the entire human genome can be sequenced within a few days for much less.

This dramatic decrease in sequencing-related costs has made it possible to introduce these technologies not only into research projects, but also into clinical practice.
The usefulness of NGS technologies resides in their ability to identify differences (“genetic variants”) between the genome from a sequenced sample (individual) and the sequence of a reference human genome.

Although the number of variants obtained when the entire human genome is analysed is big and, to this day, the meaning of only a small part of such variability is known, it is still possible to sequence the complete genome of an individual (whole genome sequencing-WGS) and to identify genetic variants known for being associated with an increased risk of developing a disease, genetic variants that have an influence over metabolism of drugs, those known for being associated with weigh and metabolism or other genetic variants with known significance. It is important to highlight that not all potentially identified variants have the same importance and relevance to an individual´s health. In order to predict the impact of a genetic variant found in an individual, a comprehensive analysis of the specific genomic and physiological context must be performed in each case.

Looking ahead, it is certainly possible to anticipate that whole genome sequencing will be present in all areas of healthcare and interpreting its results will be the biggest scientific and translational challenge.