LUCA (LAST UNIVERSAL COMMON ANCESTOR) - SCIENCE & TECHNOLOGY
WHY IN NEWS?
In a
new study, scientists have said the last universal common ancestor (LUCA) could
have formed just 300 million years after the earth formed.
- Origin of Life Forms: LUCA
is believed to be the single cell from which all three branches of life
(bacteria, archaea, and eukarya) originated.
- Fossil Evidence: There
is no direct fossil evidence of LUCA.
- Modern Genomes: Shared features among modern genomes support
the existence of LUCA.
- Molecular Clock Theory: This
theory helps reconstruct the 'tree of life' by estimating the time between
evolutionary events based on mutation rates.
- Phylogenetic Tree
Construction: Researchers at the
University of Bristol and Exeter estimated LUCA's origin to be around 4.2
billion years ago using a molecular clock.
- Genome Characteristics: LUCA
had a small genome with about 2.5 million bases encoding approximately
2,600 proteins.
- Metabolites: Compounds
produced by LUCA's metabolism could have created a secondary ecosystem,
enabling the emergence of other microbes.
- Earliest Fossil Evidence: Found
in the Pilbara Craton, Western Australia, these fossils are of organisms
from around 3.4 billion years ago, indicating LUCA originated about a
billion years earlier.
Source: https://www.thehindu.com/sci-tech/science/searching-for-luca-the-first-life-form-from-which-all-other-life-descended/article68409763.ece