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takyon [soylentnews.org] writes:

Scientists at Leiden University have found evidence that a "second layer" of information in DNA [leidenuniv.nl] can influence protein expression:

Leiden theoretical physicists have proven that not only the genetic information in DNA determines who we are, but also DNA's mechanics. Helmut Schiessel and his group simulated many DNA sequences and found a correlation between mechanical cues and the way DNA is folded.

[...] Now for the first time, Leiden physicist Helmut Schiessel and his research group provide strong evidence that this second layer of information indeed exists. With their computer code they have simulated the folding of DNA strands with randomly assigned mechanical cues. It turns out that these cues indeed determine how the DNA molecule is folded into so-called nucleosomes. Schiessel found correlations between the mechanics and the actual folding structure in the genome of two organisms—baker's yeast and fission yeast. With this finding we know that evolutionary changes in DNA—mutations—can have two very different effects: the letter sequence encoding for a specific protein can change or the mechanics of the DNA structure can change, resulting in a different packaging and accessibility of the DNA and therefore a different frequency of production of that protein.

Multiplexing Genetic and Nucleosome Positioning Codes: A Computational Approach [plos.org] (open, DOI: 10.1371/journal.pone.0156905)

Original Submission