A significant scientific paradigm has been challenged by new research from the University of Cambridge, which has revealed that DNA, when subjected to stress, does not tangle into knots as previously believed. Instead, the genetic material coils into organized, spring-like structures known as plectonemas.
The study employed an innovative approach using nanopores—minuscule openings designed for single DNA strands. By guiding DNA through these pores in an alkaline saline solution with applied voltage and fluid flow, researchers induced rotation. This process generated enough torque to twist the DNA molecule. Previously, irregular current signals observed during this process were attributed to knot formation. However, a more detailed analysis confirmed these signals were indicative of plectonemas, which are tightly wound, ordered spirals.
This discovery has profound implications for understanding DNA dynamics under stress, with potential impacts on molecular genetics and biotechnology. The research highlights that while DNA can be viewed as a uniform elastic rod globally, its mechanical properties can vary locally based on its sequence organization, playing a crucial role in biological functions.
The advancement of nanopore sequencing technology, which allows for real-time DNA analysis without amplification or labeling, has been pivotal in these investigations. This technology, pioneered by Oxford Nanopore, offers benefits such as ultra-long read lengths and portability, facilitating a deeper understanding of complex molecular structures and behaviors. This re-evaluation of DNA's stress response not only refines our knowledge of genetic material but also opens new avenues for applications and a more nuanced appreciation of life's fundamental mechanisms.