The basic process that kept humans and other animals alive evolved over 600 million years ago in a single-celled creature, scientists say
Avi Blizovsky
We all evolved from something like this
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A study published in the journal Science highlights the genetic lineage of the ancestral cell that we all carry in every cell in our body.
The way our cells function, grow and communicate with other cells is using molecules and methods that first appeared a long time ago, when most advanced life forms were bacteria that lived in the sea.
Studies done in single-celled organisms with ancient roots led the scientists to this far-reaching conclusion. This sheds light on one of the most dramatic evolutionary leaps in the history of life - the origin of animals. The development of animals from their unicellular ancestors is one of the most important milestones in the development of life. The identity of that ancestor and how this development occurred still remains a mystery.
Clues to what happened may be found in the molecular machinery of the choanoflagellates, a group of 150 species of transparent unicellular organisms that move using a whip-like tail.
Scientists have long suspected that they may be modern examples of the ancestors of the first multicellular organisms, or the metazoans, which looked like this when they lived over 600 million years ago.
In 2001 it was discovered that they have a type of molecular sensor commonly found in multicellular organisms. Now we will discover that they have basic properties at the molecular level that were used in animals.
"We've found a toolbox in cell biology that becomes very controversial before the dawn of animals," said Sean Carroll of the Howard Hughes Medical Center at the University of Wisconsin-Madison.
The ancient soup
The molecular process that Sean Carroll and his colleagues Nicole King and Christopher Hittinger studied allows cells to communicate and interact with each other. Such a pattern involves many basic processes at the cellular level. They also play an important role in cancer cells and sensory functions such as hearing in animals. However, the exact role of these molecules in choanoflagellates still remains mysterious.
Despite this, it seems that the molecular process that seems to have been developed by the animals has its origin in the primordial soup of the single-celled microscopic creatures.
This is consistent with the idea that evolution improvises, it connects in a global way tools that already exist, and does not invent a new organ for each action. says Nicole King, University of Wisconsin-Madison
With the choanoflagellates the scientists are convinced that they have chosen the right organism for understanding what happened at the dawn of animal evolution. The next step in their work, say the researchers, is to compare the genes that characterize animals and find among them the genes that are common to all animals and their close ancestors.
They know evolution in action
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