The Cosmic Cause of DNA’s Twist!
Biologists and chemists do not know why all known life prefers the DNA to be ‘right-handed’. “Chiral” molecules exist in dual forms that mirror each other.
It is observed that most chemical reactions produce even amounts of both right and left-haded molecules, so theoretically, a DNA or RNA molecule comprised of left-handed nucleotides would react and create life just like one made of right-handed ones.
Yet all life on earth maximally violates chirality. Some researchers believe this reason to be random: But, since the 1800’s scientists including Louis Pasteur, recognized the asymmetry in life’s molecules, pondering whether biology’s innate handedness has deeper roots.
“This is one of the links between life on Earth and the cosmos,” said Pasteur.
It’s an enduring mystery to this day. Could the ‘handedness’ of elementary particles cause DNA’s twist? Two astrophysicists say ‘Cosmic Rays May Explain Life’s Bias for Right-Handed DNA, but special guest Prof. Lee Cronin is dubious.
What is chirality and What does it mean for organic molecules to be chiral? How did chirality emerge on Earth and what are possible explanations for the right-handedness of living molecules? Hear Lee Cronin discuss possible explanations for chirality on Earth.
Does chirality spawn life or does life cause chiral excess? Modern explorations and experiments on the origin of life from inorganic molecules.
References:
Cosmic Rays May Explain Life’s Bias for Right-Handed DNA https://www.quantamagazine.org/cosmic-rays-may-explain-lifes-bias-for-right-handed-dna-20200629
Prof. Lee Cronin’s Lab: http://www.chem.gla.ac.uk/cronin/ Follow Prof. Lee Cronin on Twitter https://twitter.com/leecronin
The Astrophysical Formation of Asymmetric Molecules: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6463258/
Chiral Molecules in the Interstellar Medium: https://public.nrao.edu/news/2016-chiral-gbt/
Cosmic Rays and the Chiral Puzzle of Life: https://arxiv.org/abs/1911.02525 Cosmic Rays and the Handedness of Life: https://www.scientificamerican.com/article/cosmic-rays-and-the-handedness-of-life/
In Warm Greasy Puddles, the Spark of Life?: https://www.quantamagazine.org/in-warm-greasy-puddles-the-spark-of-life-20160317/
Scripps Blackmond Laboratory: https://www.scripps.edu/blackmond/
Simons Collaboration on the Origin of Life: https://www.simonsfoundation.org/life-sciences/origins-of-life/simons-collaboration-on-the-origins-of-life/
Links to videos mentioned: Lorentz Violation Explained: Sean Carroll https://youtu.be/egwg8ooc-L0
Luca Legnani on Primo Levi, the Origin of Life, and Chirality: https://youtu.be/RAqY8P0nTKQ
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