Genetic evidence about ancient populations is cool. Sometimes it tells you things that are fairly intuitive, like that the early Native Americans peopled the continent very quickly, and that at some point they got a visit from some Pacific populations.

The Extremely Fast Peopling of the Americas

Were There Two Routes into North America?

At other times, genetic evidence (or the way it is interpreted) tells us some things that make sense and others that don’t. Take this article for example:

Traces of Mystery Ancient Humans Found Lurking in Our Genomes

On the one hand, the genetic evidence presented here is said to indicate that there was once a lot more genetic diversity among humans than there is now. That makes a ton of sense, especially if you believe in a bottleneck such as the Flood.

On the other hand, this article also asks us to believe that these distinct human populations stayed away from each other for up to 700,000 years (!) and then met up again and interbred. That is really hard to swallow. How in the world did they manage not to bump into each other for that long? The world isn’t that big, is it?

One of the human (or “vaguely human-like,” as the article so flatteringly puts it) populations mentioned in the article above is the Denisovians, apparently a very hearty Central Asia population that was well adapted to high altitudes. For those who believe historical evidence that giants once walked the earth, the following article might be suggestive:

‘Spectacular’ Jawbone Discovery Sheds Light on Ancient Denisovians

But, back to my ambivalent relationship with genetic evidence. Every once in a while, your world gets rocked by a “fun fact” like this one:

“We share 50% of our genes with bananas.”

The “fun fact” has now become a “confusing fact.” Waitaminit! If that is true … then genetic analysis tells us basically nothing about the nature of a thing … then all of this is … worthless?

No, not really. It has helped me to remember that genes are not words or sentences, they are libraries. It is easy to imagine two vast libraries which have a 50% overlap (encyclopedias, dictionaries, and the like) but diverge wildly in the other 50% (one is all philosophy and ancient history; the other is all Dave Barry). That helps. Some. But it’s also a reminder that even the experts have “read” only a few volumes from any given library.

Sometimes genetic evidence tells a different story than that told by archaeology (with its many assumptions) or linguistics.

Divided by DNA: The Uneasy Relationship Between Archaeology and Ancient Genomes

I am not the only one troubled by this.

I guess it’s just one more reminder of just how much we don’t know.