Research related to LUCA and origin of life

Source- This post on the Research related to LUCA and the origin of life has been created based on the article “Glimpses of LUCA, the life-form from which all other life descended” published in “The Hindu” on 17 July 2024.

All life on Earth can be traced back to the Last Universal Common Ancestor (LUCA). A recent study suggests that LUCA likely existed just 400 million years after Earth’s formation. Further analysis indicates that this organism probably had an early immune system, suggesting it was already combating viruses.

Early Theories on the Origin of Life

1. In the 1920s, Alexander Oparin and J. B. S. Haldane proposed the first theories about the origin of life, suggesting that molecules in a “primordial soup” self-organized into early life forms. This idea is known as the Oparin-Haldane hypothesis.

2. Supporting Experiments:

i) The Miller-Urey experiment in 1952 demonstrated that under certain conditions, inorganic compounds could form amino acids, the building blocks of proteins.

ii) Stanley Miller and Harold Urey mixed methane, ammonia, and water, and applied an electric current, simulating lightning, which resulted in the creation of amino acids.

iii) While the experiment’s environmental assumptions may not fully align with early Earth conditions, it proved that amino acids could arise from inorganic molecules.

3. Alternative Theories: Some researchers propose that meteorites brought the building blocks of life to Earth. Discoveries of extraterrestrial organic material and amino acids on asteroids support this hypothesis.

About LUCA and the Molecular Clock

i) The molecular clock theory, proposed by Emile Zuckerkandl and Linus Pauling and later refined by Motoo Kimura, helps estimate the timing of evolutionary events by analyzing the rate of genetic mutations.

ii)  Researchers calibrate the molecular clock using known evolutionary events and fossil records.

iii) A study published in Nature Ecology and Evolution by researchers from the University of Bristol and Exeter estimated that the Last Universal Common Ancestor (LUCA) originated around 4.2 billion years ago, shortly after Earth formed.

iv)  This suggests LUCA predates previous estimates of life’s origin on Earth, which were based on fossil records dating back 3.4 billion years.

v) The Last Universal Common Ancestor (LUCA) likely had a small genome with about 2.5 million bases and around 2,600 proteins, sufficient for survival in its niche.

vi)  Metabolites produced by LUCA could have supported a secondary ecosystem, aiding the emergence of other microbes.

Implications and Significance

i) These findings significantly advance our understanding of how life emerged and evolved on Earth.

ii)  The study also enhances our ability to search for similar forms of life across the universe.

iii)  Insights from this research may contribute to engineering synthetic organisms for industrial, chemical, and biological processes, and creating ecosystems on other planets.

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