Origin & Evolution of Life

Fatty Acid Vesicles As Hard UV-C Shields for Early Life

By Keith Cowing
Press Release
January 13, 2023
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Fatty Acid Vesicles As Hard UV-C Shields for Early Life
Scattered and absorbed light by a fatty acids vesicle. Light from the sun travels through a thin layer of ocean water and interacts with the vesicle. Some of the light is absorbed by the fatty acids and the DNA, RNA, and other fundamental molecules assumed to have been dissipatively structured within the vesicle. Another part of the light is scattered, mainly in the forward direction. The scattered light is plane polarized and some of it may then be totally internally reflected at the ocean surface, producing circularly polarized light which may have been important in giving rise to the homochirality of life.

Theories on life’s origin generally acknowledge the advantage of a semi-permeable vesicle (protocell) for enhancing the chemical reaction-diffusion processes involved in abiogenesis.

However, more and more evidence indicates that the origin of life concerned the photo-chemical dissipative structuring of the fundamental molecules under UV-C light. In this paper, we analyze the Mie UV scattering properties of such a vesicle made from long chain fatty acids.

We find that the vesicle could have provided early life with a shield from the faint, but dangerous, hard UV-C ionizing light (180-210 nm) that probably bathed Earth’s surface from before the origin of life and until perhaps 1,500 million years after, until the formation of a protective ozone layer as a result of the evolution of oxygenic photosynthesis.

Iván Lechuga, Karo Michaelian
doi: https://doi.org/10.1101/2023.01.01.522439

https://www.biorxiv.org/content/10.1101/2023.01.01.522439v1

Astrobiology

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