Last Universal Common Ancestor(LUCA)

The Last Universal Common Ancestor(LUCA) was the cell through which all life forms were made. This microbe lived around 4 billion years ago.

Nasa says that this microbe probably lived an ‘alien life’ as it was underground and did not need air and made its own food in the dark. It lived in a metal rich environment which led LUCA to depend on hydrogen, nitrogen and carbon dioxide which eventually turned into ammonia.

A growing bacteria can take the genes from the elements around them and incorporate it into their DNA system. The same way over 4 billion years ago, LUCA did the same thing.

A group of scientists at NASA discovered that LUCA only had 355 genes from the original 11,000, but such a small group of genes would not help LUCA survive as they cannot support life. There seem to be missing nucleotide and amino acid biosynthesis. The scientists did not even have a complete ribosome. Though, they speculated that LUCA could have used various molecules in the environment to synthesize necessary genes, such as amino acids to survive. Scientists at Nasa, speculate that biochemistry was still primitive at this stage.

LUCA lived in hydrothermal vents in the ocean and used hydrogen as an energy source. It also had a particular gene for making an enzyme that helps extremophiles exist in high-temperature environments.

LUCA is not the origin of life. Thus, it is called the tree of life as it was the last shared ancestor on earth. Life after that, broke into three branches into bacteria, eukaryotes and archaea. The earliest evidence of life was present approximately 3.7 billion years ago. Presumably, life also may have existed before that.

Exploring LUCA gives us hope of life on other parts of the universe as hydrothermal vents are extremely common in other parts of our solar system.