That would suggest that the ancestor of all living things LUCA was made of DNA.
The phrase "that would suggest ..." is a conditional sentence. But I can not define the if clause.
So could you please explain it to me?
The fuller text is here:
Ida and Luca existed so long ago that if any rocks ever harboured traces of their existence, they were long ago subsumed by tectonic forces and melted into Earth’s depths. But we can find clues to their nature in every living cell today, including our own. Cells use the same genetic code embodied in DNA. That would suggest that the ancestor of all living things, Luca, was made of DNA.