[Virginia-American]

Sure, it could have been natural (ala Evolution), but it could also have been un-natural (ala Intelligent Intervention).

What would be a good way to distinguish the hypotheses?

What sort of Intelligence would put leg genes in a whale's genome? How would you tell that from a whale evolving from a terrestial animal?

[Southack]

"What sort of Intelligence would put leg genes in a whale's genome?"

Perhaps it would be the same sort of intelligence that would put ancient CP/M code in the kernal to Windows NT. In other words, one shouldn't be surprised to see lazy designers. Code re-use is a great thing, but streamlined it's not. Whether you are looking at modern human programming or DNA code, you'll find lots of useless, vestigal code out there...

[Southack]

Sure, it could have been natural (ala Evolution), but it could also have been un-natural (ala Intelligent Intervention).

"What would be a good way to distinguish the hypotheses?" - Virginia-American

A good way would be to see evidence in the lab of DNA self-forming (i.e. Evolution or Abiogenesis) or being formed by Man (i.e. an Intelligent Designer), but I wouldn't be so bold as to claim that that is the only way to distinguish the two (although I'll leave other examples up to you).