Human Evolution

What is the last universal common ancestor (LUCA)?
Answered by Science Channel
  • Science Channel

    Science Channel

  1. Did you know that every living thing is related to every other living thing? The last universal common ancestor, also known as LUCA, was essentially the foot in the door that life needed to arise and eventually dominate the planet -- some call it the "great-grandparent of all living things" [source: ScienceDaily]. Basically, every living thing on the planet shares the same genetic code. We even share a single descendent in the form of a single-celled organism that existed more than 3 billion years ago. Some biologists think the last universal common ancestor originated from simpler strands of nucleic acids, or a random mass of molecular parts.

    In trying to create what is basically a family tree of all life (at which LUCA is at the center), scientists are trying to reconstruct LUCA. Since all living things come from three branches of life -- archaea, bacteria and eukaryote -- the researchers' job is to figure out which traits of these three can be traced all the way back to LUCA [source: Poole]. Even for the experts, this is quite a complicated undertaking. Some scientists have even suggested that there might be more than one LUCA, while others think there can only be one.

    While research has been underway for years, recent evidence suggests that LUCA may actually be more complex than scientists have speculated. According to a 2011 research study in the journal Biology Direct, researchers have new evidence that shows that LUCA was more sophisticated than originally thought, and is definitely recognizable as a cell [source: ScienceDaily]. For those working on LUCA research, it's an exciting discovery, but there are still plenty of secrets about LUCA left to uncover.

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