Okay, first - I'm not a proponent of intelligent design. I do not think it's a valid scientific theory (it has no mechanism of change/design). Second, I could be wildly off on what I think I know, in which case, my apologies for the question.

My question is, I know that scientists manipulate the genes of organisms (both animals and crops we use as food). I think this could be considered legitimate intelligent design (right? I'm talking as opposed to looking at an organism and saying that this couldn't have evolved naturally, therefore it was intelligently designed).

So, mankind has modified organisms - outside of knowing we did this, can we tell they were intelligently created? If so, how? Can we tell when a genome has been altered?

Also, if I'm totally off base, please correct me.

  • $\begingroup$ to be fair we have engineered segments of their DNA, not the entire thing. $\endgroup$
    – John
    Apr 24, 2017 at 14:07
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    $\begingroup$ "To create" (to me) implies more than "to alter", which is what gene-splicing does. But that is just semantics. Can we tell if they were purposefully altered by man? I doubt it. Maybe if a particular, trademarked nonsense sequence was inserted into the genome as well, yes. But I doubt that is done (yet). These tactics have a way of backfiring on one. Animal husbandry is not the creation of an animal, but merely selecting for characteristics. Semantics matter here. $\endgroup$ Apr 24, 2017 at 14:07
  • $\begingroup$ Honestly I thought about rephrasing just because of what you suggest - all we've done is alter genomes, but I wasn't 100%. I'm open to your question as well: Can we tell if a genome was purposely altered? Should I edit my OP? $\endgroup$ Apr 24, 2017 at 14:12
  • $\begingroup$ Yeah, I answered that in my comment. I highly doubt it, but I didn't post that because I never post an answer I'm unsure of, and I didn't want to slog through a bunch of scientific literature to find out if I am correct. If you want to edit, feel free. I changed the title because left as it was, few peple would click on it. $\endgroup$ Apr 24, 2017 at 14:14
  • $\begingroup$ I did want to say that I have in mind what my friend (a CSI) has said in the past, that there is almost always evidence when a murder is committed; I grant that altering genes is not a murder, but I was thinking that the general principle might apply towards anything that mankind has messed around with. I'm probably wrong here, but that's where my head is at. $\endgroup$ Apr 24, 2017 at 14:15

2 Answers 2


One should be able to tell this from comparison of the sequence with that of the original organism in GenBank etc. The differences in an engineered organism will generally be extensive and of such a kind that a specialist in the field will be able to identify their origin and deduce that they did not arise naturally.

However there is no general and guaranteed method. If I were to engineer a single base change, there would be no way to distinguish that from a natural mutation. The only thing is that if the mutation were beneficial then it would probably have occurred naturally and I wouldn’t have needed to engineer it.

  • $\begingroup$ It has to be on a case by case basis. If I see a mouse or a fruitfly expressing jellyfish green fluorescent protein I know it cannot have acquired it by vertical transfer. That's why I deliberately mentioned a specialist or expert. The answer may not be the neat one the OP hoped for, but it's the way it is. It's like asking how an art expert can tell a genuine Picasso from a forgery. $\endgroup$
    – David
    Apr 24, 2017 at 20:24

Depends on the type of alteration.

If we are talking insertion/alteration/deletion of whole genes, we can easily discover the changes by genome sequencing and comparison.

If we are talking a single point mutation somewhere in the genome, it is harder to detect the change as such mutations can occur naturally (roughly 20-30 such mutations occur per human generation).

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    $\begingroup$ The number is higher. The 1000 genomes project estimates it around 20-30 de novo mutation per generation, see. $\endgroup$
    – Chris
    Apr 24, 2017 at 19:11

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