Genome complexity: Controlling 3-D DNA relationships (Introduction)

by David Turell , Tuesday, September 21, 2021, 18:56 (948 days ago) @ David Turell

Special controls must be in place to open up specific genes to act:

https://phys.org/news/2021-09-proteins-symphonies-genes-statistical-theory.html

"'Many scholars at the crossroad between physics and biology are now approaching what is probably the most crucial puzzle of biology," said co-author Alessandro Giuliani. "How is it possible that, starting from the same genetic background in the fertilized egg, around 400 highly differentiated cell types can arise, each endowed with a specific physiological role?"

"Biology-based theories often center on regulator proteins, called transcription factors, that biochemically conduct a symphony of genes to be expressed together. By contrast, many physicists have focused on expression waves, the rhythmic changes in expression levels across the genome, driven by relaxation and condensing of the DNA molecule itself.

"'It is something like the so-called hola, common in soccer and in other sport events, in which the spectators stand up simultaneously giving rise to a 'wave' spreading all over the stadium," Giuliani said.

"To get at the heart of the issue, the group focuses on a specific type of cell found in breast cancer with a proven track record of consistently behaving the same way to stimuli.

"They used statistical mechanics to make sense of how DNA molecules fold by assessing the collective behavior of a huge number of microscopic players in terms of ensemble properties, unlike classical top-down perspectives, like Newton's laws.

"Ultimately, the researchers landed in favor of expression waves, acknowledging that while transcription factors play a vital role, they are second fiddle to the changing shape of DNA."

Comment: Not yet fully understood, but it shows the point that DNA is not just a protein-producing code but by having its shape adjusted many possible results are produced. Only exquisite design by a designer can create this.