There are two layers of code in DNA strands, new research suggests.

The first and most-studied layer is that which dictates the anatomical decisions that make us who we are -- which proteins are produced and in what quantities.

But according to a new study out of the Leiden Institute of Physics, a second layer governs the mechanics of the DNA.

There is code in human DNA for every facet of a person's physical existence -- a chunk of code for blue eyes, a section for red, curly hair. This information isn't exactly useful for the cells building and maintaining a person's lungs or nervous system. Yet every organ and its cells contain the same strands of code.

Different cells fold their DNA in different ways to fit inside the cellular nucleus. The folding patterns affect the order in which DNA sequences are read. Scientists have hypothesized that DNA contains a second layer of code for instructions on how it should be folded.

In simulations, researchers found randomly assigned mechanical cues encouraged specific folding patterns in DNA strands. Scientists observed strong correlations between mechanical and actual folding formation in the genome of both baker's and fission yeast.

The new findings, published in the journal PLOS ONE, suggest genetic mutations can affect DNA in two ways -- manipulating both the sequencing itself and the manner in which sequences are organized.

"The mechanics of the DNA structure can change," researchers said in a news release, "resulting in a different packaging and accessibility of the DNA and therefore a different frequency of production of that protein."