You both would descend from LUCA. It’s just that you would have a second line of descent. Anyway, even if you had tons of Adam & Eve’s DNA, through some statistical fluke, there would be no way to determine that as long as their genomes weren’t bizarrely distinct from normal human variation. GAE is untestable, right?
Still, that doesn’t mean that de novo creation of organisms is consistent with biological science. It’s consistent (in the minimalist meaning) with the genetic data, but there’s a lot more to biology than genomic sequences.