Last universal ancestor (LUA), the hypothetical latest living organism from which all currently living organisms descend. Also LCA (last common ancestor) or LUCA (last universal common ancestor).

The last universal ancestor already had all of the properties that are shared by all currently living organisms, such as a (prokaryotic) cell structure, DNA, the modern genetic code and mRNA, tRNA and ribosome mediated transcription.

Notes on possible misconceptions:

1. The LUA wasn't the first living organism ever,
2. neither was it the most primitive possible living organism, and
3. it wasn't alone but had plenty of contemporaries inhabiting the world ocean.

All its contemporaries have since become extinct, however; only LUA's genetic heritage lives on to this day. Carl Woese proposed [1] that our pre-LUCA genetic heritage derives from a community of organisms, rather than an individual.

See also

Common descent

Most recent common ancestor