what's "lf clause" in the sentence "that would suggest..."?

Question

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.

Answer 1

"That would suggest" is not necessarily part of an if-clause. Instead it's a sentence fragment (not a complete sentence in itself) that is a logical consequence of the previous assertion. Paraphrasing:

Since all the cells of living organisms contain the same embedded DNA, that would suggest their common ancestor (Luca) also had the same DNA.

It would be possible to rewrite this is an if-then statement:

If true that all the cells of living organisms contain the same DNA, that would suggest their common ancestor (Luca) also had the same DNA.

Note: This paragraph is not particularly well-written, as it contains numerous redundancies, sentence fragments, and misused words (e.g. "embodied" rather than "embedded"). The author may not be a native speaker, or perhaps just a careless writer. I would not worry too much if you read things in the text that seem strange.