If certain genes are found in all living species, it is in fact because they were passed down through a direct line from the same common ancestor. However, by studying how these genes have evolved over time, it should theoretically be possible to assess when that ancestor lived. That’s the strategy used by researchers from the United Kingdom, the Netherlands and Hungary in a study published July 12. Nature and Evolution Environment.
Thus, these scientists reconstructed a “family tree” of living organisms, from which they estimate the age of the most recent common ancestor at 4.2 billion years (in English, LUCA, for 4.2 billion years). last universal common ancestor). This is much older than other researchers have suggested, only a few hundred million years after our planet formed.
Subscribe to our newsletter!
So you don't miss any scientific news and know everything about our efforts to combat fake news and misinformation!
The organism in question was likely a single-celled organism without a nucleus, similar to bacteria. But it was also more advanced than many researchers have suggested, too. comment in new world One of the study's authors. Its genome allowed it to produce about 250 proteins. It lived without oxygen and got its energy from hydrogen. The researchers noted that since it already had genes to protect it from ultraviolet radiation, it likely lived on the ocean's surface, but also perhaps in the depths, near the ocean. hydrothermal drilling.
Furthermore, this grandfather may have been part of From the ecosystem inhabited by other primitive bacterianow extinct. It also had a primitive system to defend itself against viruses, which were already present as well.
By placing LUCA 4.2 billion years agoThis study shows that it appeared before the “Late Great Bombardment,” the name given to the period of increased meteorite impacts on Earth and the Moon. Scientists previously thought it was impossible for life to survive this event, which is why LUCA was placed 3.8 billion years ago.
However, the existence of the late Great Bombardment is now in question, the study's authors wrote. However, this argument does not seem to be enough to convince the French scientist who interviewed him. new worldFor him, this finding means that the strategy used in this study so far, LUCA, is problematic.
One of the study’s authors acknowledges that these results are just a starting point for learning more about our common ancestor. He agrees that the proposed model may have flaws, but that they could be corrected in future studies.
