On Monday, March 10th, UCL Science Magazine had the pleasure of hosting a series of academic seminars on ‘Interdisciplinarity in STEM,’ led by UCL lecturers Dr Graeme King and Dr Amy Cottle. A huge thank you to our speakers for their fascinating insights and to our attendees for contributing to such a thoughtful Q&A and discussion! By Diya Asawa and Kai Mor
Exploring the Molecular Forces Shaping the Human Genome - Dr Graeme King (UCL Lecturer in Single Molecule Biophysics)
Dr King’s presentation centred around the fascinating, intricate molecular forces which shape the human genome, exploring the principles underlying DNA compaction, techniques used to manipulate single molecules, and the impact of these forces on cellular machinery and function.
The human genome should strike a fine balance between compaction and accessibility. Compaction is facilitated by DNA-binding proteins like histones, which condense the DNA and allow its dense packaging within the nucleus. On the other hand, this tightly packed state needs to be unwound at specific times to allow cellular machinery to access the genome and carry out processes like replication and translation. Molecular forces such as torsional stress are not just by-products of polymerase activity and protein-binding to DNA - they play an active role in regulating helical unwinding and protein interactions with the DNA! This has serious implications for techniques like CRISPR-Cas9, where off-target binding can lead to inaccurate DNA unwinding, causing errors in gene editing.
Dr King also discussed the ground-breaking application of lasers or optical tweezers to trap single biological molecules and organelles in place, even within moving cells! These optical tweezers can be used to tether a single molecule of DNA to two optically trapped beads. Scientists can then move these beads to stretch and manipulate the DNA molecule, generating force-extension curves which help elucidate information about DNA mechanics and protein interactions. As researchers discover new interdisciplinary techniques to observe and manipulate DNA at microscopic levels, these insights could help advance a range of research areas within genetics, molecular biology, and physics!
The Nature of Dark Matter - Dr Amy Cottle (UCL Lecturer in Experimental Particle Physics)
Dr Cottle's presentation began, like our universe, with a bang. It focused on the enigmatic nature of dark matter, postulating its existence through observations of our cosmos and commenting on its gravitational interactions within galaxies and the Bullet Cluster. Although it constitutes approximately 85% of our universe's mass, dark matter remains undetected because it barely interacts with ordinary matter. Weakly Interacting Massive Particles (WIMPs) are one of the key theoretical candidates for dark matter, and they lie beyond our Standard Model of particle physics.
Dark matter experiments need an ultra-sensitive, low-background detector to measure the tiny recoil energies of potential dark matter interactions. The LUX-ZEPLIN (LZ) experiment uses a pioneering detector located at South Dakota's Sanford Underground Research Facility. Through the utilization of 10 tonnes of liquid xenon in a time-projection chamber, the LZ experiment could theoretically capture the rare interactions between WIMPs and xenon nuclei. Dr Cottle highlighted LZ's incredible progress - the experiment achieved ground-breaking sensitivity, holding the world record for its exclusion limit for WIMP-nucleons interactions!
Dark matter may still be elusive, but the future of WIMP interaction detection seems bright. Dr Cottle teased the next-generation XENON-LUX-ZEPLIN-DARWIN (XLZD) experiment detector with a proposed 60-80 tonne xenon capacity, poised to probe even fainter signals of not just a range of dark matter candidates, including WIMPs, but also astrophysical neutrinos. With the Boulby Underground Laboratory, located in a salt mine at Yorkshire, being a perfect location to host such an experiment, the UK is well positioned to be the next global epicentre for dark matter research. Ultimately, dark matter research seeks to tackle one of science's greatest mysteries. It demonstrates a long standing effort by humanity to push the boundaries of our knowledge in hopes of better understanding the universe to which we reside in.
