Everything that makes us unique is in our DNA. However, more than twenty years ago, a hypothesis was put forward that a person is the result of not only his genetic code, but also information signals that determine how the code is formed inside the cells of the body. Now, Dutch theoretical physicists have confirmed that the second layer of information does exist.
Proteins are the building blocks of our body. Through a sequence of four basic nitrogenous bases that make up the nucleic acids - guanine, adenine, thymine and cytosine - DNA dictates which proteins and how much to produce. Although the cells in our body contain the same DNA sequence, they make up different organs. This suggests that additional processes are taking place in the cells.
DNA molecules are packed extremely tightly in our cells. If you take a single cell and untangle all the DNA molecules that it contains, then their total length will be about two meters. One theory from the early 1980s suggested that the mechanical properties of DNA determine how individual molecules fold inside a cell. It affects how the genetic code is read, which is an extra layer of information at the top of the sequence of nitrogenous bases in the DNA helix.
A team of researchers led by Helmut Scheisel of the Leiden Institute of Physics conducted computer simulations to test the hypothesis. Physicists have received strong evidence that mechanical signals do exist. To do this, the scientists transmitted disordered signals to the DNA strands of two organisms - baker's yeast and fissile yeast - and found that their DNA molecules fold in different ways.
With their findings, the team explains that mutations in DNA depend on two things: the unique nucleotide sequence and the mechanical structure of DNA, which affect how the genetic code is read and the type and amount of proteins the body makes.