The answer has always been yes. The implication is that we all belong to some universal tree of life. And at the base of this tree - some have imagined - there sits a mild-mannered microbe that lived more than 3 billion years ago, unaware that its genes would be the starting point of an entire planet's worth of highly differentiated life.
However, this organism, the so-called last universal common ancestor (or LUCA), may be just a fantasy.
"Our perspective is that life emerged from a collective state, and so it is not at all obvious that there is one single organism which was ancestral," said Nigel Goldenfeld from the University of Illinois at Urbana-Champaign.
The organisms belonging to this collective state would have shared genetic information from neighbor to neighbor, rather than solely from parent to offspring. Goldenfeld is leading a new NASA Astrobiology Institute (NAI) team that aims to provide a clearer understanding of this early stage of evolution.
"We are hoping to find fossils of the collective state in the genomes of organisms," Goldenfeld said.