Last week, Kieran Healy posed an interesting problem:
[W]hat if, long, long after our disappearance, some other species arose on earth at least as intelligent as us and eventually started doing evolutionary and molecular biology. Let’s say they have a working theory of evolution much like our own. Now say for the sake of argument that a bunch of transgenic organisms produced by humans have survived and prospered in the interim. So our future biologists find things like a bacteria that produces insulin, or a plant that secretes insecticide, or rice that is high in beta carotene, or more exotic stuff as needed.
I’m wondering, would such organisms even present themselves as empirical anomalies? (That is, how much would you have to know about genomes and evolution for them to seem odd?) And if they did seem odd, how would they be explained? That is, would the evidence of their intelligent design by a previous, now-extinct species be clear? You can see that I’m just irony-mongering here. Would some Arthropod-staffed functional-equivalent of the Discovery Institute point its claw at some of these organisms, saying they were anomalies that could only be explained by the intervention of a divine intelligence? Would Charles Crustacean find a story that could account for their evolution by natural selection? I’m particularly interested in whether the artificial provenance of transgenic organisms would be clear on internal evidence alone. I don’t know anything about this stuff, so probably the answer is “Yes” for reasons obvious to experts. But if it weren’t …
I've been think about Kieran's questions since reading them, and I've concluded that unless traces of our existence and evidence of our technology persisted, the answer is probably “No.”
I explain why the answer is “No,” below the fold, and I'll explore the implications of this answer later tonight or on Thursday.
The three domains of life. (From the University of California Museum of Paleontology)
Phylogenetic relationships among bacteria, mitochondria, and chloroplasts. (From the UCMP's Understanding Evolution website)It is now widely accepted that mitochondria and chloroplasts are endosymbionts. Single-celled ancient ancestors of modern animals and plants engulfed the bacterial ancestors of modern mitochondria. For whatever reason that bacterium wasn't digested. It began to reproduce inside the ancestral eukaryote, the host came to depend on it for energy to sustain its metabolism, and the bacterium came to depend on the host for its nutrition. The result was a new organism with two genomes that were only distantly related. In the lineage leading to green plants a second endosymbiotic event occurred when a eukaryote engulfed a photosynthetic cyanobacterium. The host cell used energy fixed by photosynthesis in the cyanobacterium, and the cyanobacterium depended on nutrients supplied by the host cell. In modern plants and animals, many genes have been transferred from both the mitochondrial and the chloroplast genomes to the nuclear genome. So the nuclear genome of a modern eukaryote is a mosaic of sequences, most directly inherited from the ancestral cell that engulfed the proto-mitochondrion and proto-chloroplast and a few that were originally found in the mitochondrion or chloroplast that have been transferred to the nucleus.
In short, we have within our own bodies gene shuffling of the type that Kieran postulates. By reconstructing the evolutionary relationships among genes and genomes, we're able to recognize this shuffling. And future biologists who were “at least as intelligent as us” would be able to do the same with genes we splice from bacteria into rice, from insects into tomatoes, from squid into pigs, from inects into sheep, or any other kind of of transfer we might imagine doing. What they wouldn't be able to do, unless they had evidence (a) of our existence and (b) evidence of our technology is to infer that we were responsible for the gene shuffling.
There would be much argument and debate about the mechanisms that produced the shuffling, but if our future biologists are good empirical scientists, they will consider as possible mechanisms only those types of processes for which they have empirical evidence. They will not take the gene shuffling we did as evidence of our existence.
Proponents of intelligent design creationism might be cheering at this point: “Yay! He's admitted it. Here's a (hypothetical) example where we know a human designer was involved, and our esteemed evolutionist admits that he can't detect that involvement.” I'll explain later why their enthusiastic cheers should be gut-wrenching wails.3 For now, just think about that second sentence: “Here's a (hypothetical) example where we know a human designer was involved, and our esteemed evolutionist admits that he can't detect that involvement.”
1The Human Genome Project should really have been called the Human Nuclear Genome project. Human mitochondrial sequences were available by the time the HGP started.
2A group that used to be called the “blue-green algae.”
3Assuming that their objective is to get intelligent design creationism taught as a scientific alternative to modern evolutionary ideas in science classes.
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