In the year 2000, after 15 years of research using a combination of genetic and computational techniques, scientists from six countries managed to discover the location of all of the genes that determine, among other things, eye color, hair type, blood type and even the individual’s sex. For the investigation, the genome (genetic material contained in every cell of the organism) used was from 10 to 20 samples taken from anonymous donors, from different ethnic and racial groups.
The first stage was to make a physical and genetic map of the genome. This drawing helped determine the distances between the different locus (position a gene takes up in the genome).
The second stage consisted on using enzymes to cut up the DNA and split the chromosomes into fragments. A procedure called electrophoresis in gel was then applied to them, which consisted on charging up an electric field for them in order to separate the fragments by size, generating patterns which, analyzed by a computer, showed the sequence of the bases of the chromosomes’ fragments.
In 2000, these pieces had already been put together like the pieces of a puzzle, creating a rough draft. It provided revelations on the human genome, as it showed that the sequence of bases had around 3,200 million letters. In addition, it was proven that 97% of DNA is trash and only the remaining 3% correspond to the genes that contain encoded instructions to create proteins. Instead of there being 100 thousand genes, as was believed before, today it is believed that there are between 30 and 50 thousand.
