Last Universal Common Ancestor:
In a new study, scientists have said the last universal common ancestor (LUCA) could have formed just 300 million years after the earth formed.
- Researchers believe all three branches of life namely bacteria, archaea, and eukarya originated from a single cell, called the last universal common ancestor (LUCA).
- LUCA had a small genome with about 2.5 million bases and 2,600 proteins, sufficient for survival in its unique environment.
- LUCA’s metabolites might have created a secondary ecosystem for other microbes to emerge, and it possibly had immunity genes to fight off viruses.
- Though there is no fossil evidence to support the existence of LUCA, modern genomes share so many features that provide some insights.
- However, the theory of the molecular clock allowed scientists to reconstruct the ‘tree of life’.
- As per theory, the rate at which mutations are added or removed from a population’s genome is proportional to the rate of acquiring new mutations, which is constant.
- The mutation rate varies between species.
- Based on the findings, researchers created a method to estimate the time between evolutionary events by using known mutation rates and linking genomes to specific events like the evolution of the first mammal or the age of fossils as benchmarks.
- Based on the earlier findings of fossils in the Pilbara Craton in Australia, the earliest life forms were believed to be date back to 3.4 billion years ago.
- Overall, these findings are crucial for understanding how life began and evolved on Earth and for seeking similar life forms elsewhere in the universe.
- These evolutionary insights will boost efforts to engineer synthetic organisms for various processes on Earth and to create or manage ecosystems on other planets in the future.
