The Similarity of Human DNA and Chimp DNA: It’s Not So Special After All

By L. Alfred James

Aluminum Chimp DNABelieve it or not, aluminum was once classified as a precious metal. It was believed to be so special, that bars of aluminum were exhibited at a huge international exposition (the Exposition Universelle) in 1855. Because it was assumed to be so rare, one ounce of aluminum actually cost more than an ounce of gold. (Imagine what you could have bought with a case of Reynolds Wrap!) Aluminum was a hot commodity.

But in 50 years things changed dramatically. First, it was realized that aluminum is extremely abundant in the earth’s crust. It’s actually the third most abundant metal on the planet. It isn’t rare at all. Second, a cost-effective process for refining it was invented and aluminum products flooded the market. Thus, the price of aluminum went from $12 a pound in 1880 to just 20 cents a pound in 1930. The assumed rarity was proven to be just a hasty generalization, and the price plummeted. One can only imagine the despair of those folks who invested loads of money in this metal. (Napoleon III was among those who were smitten with aluminum. His most honored guests dined with aluminum cutlery while those deemed less worthy had to settle for the silver cutlery.)1

Aluminum Chimp DNAI believe that a similar despair is awaiting those who assume that the similarity of chimp DNA and human DNA is a really unique thing, something really special. The uniqueness of this “fact” is touted everywhere. You hear it constantly bandied about: “Human beings and chimpanzees have DNA that is 98% identical. It is so friggin’ obvious that we are the product of evolution!” Some evolutionists even give a number as high as 99.44%. But whatever number they give, there are two assumptions being made in these pronouncements:

  1. As a percentage, the similarity of human and chimp DNA is an extremely high number. As such, this similarity is a very unique and special thing. It is so unique it cries out for an explanation.
  2. The best explanation, obviously, is that human beings and chimpanzees have a common ancestor.And a third assumption follows:
  3. Anyone who denies human evolution in the face of such powerful evidence must be hopelessly biased and intellectually dishonest.

Being spun like this, this similarity (when made into a number) has been extremely persuasive to many people. In my opinion, the fossils that evolutionists stick in our collective face is probably the most convincing form of evidence for human evolution (largely because of the persuasive nature of images). But this similarity it also quite convincing. It has had a huge impact. It is probably the second most powerful piece of evidence for their view, so it is something that we can’t leave unaddressed.

Nonetheless, it doesn’t take long to see that the specialness of this similarity has been greatly exaggerated. It’s really not all that special. It is definitely not the hot intellectual commodity it has been made out to be. Indeed, it’s only about as special as aluminum. Why do I think this?

First, there are different ways of counting similarities in the DNA of two species. And the percentage you end up with depends on how you do the counting. What counts as “similar” DNA and what counts as “different” DNA has been the subject of serious disputes. It is not at all as straightforward as it often sounds. You’ve probably heard about corporate accountants who can “cook the numbers” to make their corporation’s performance look grandiose (when it is really mediocre). Likewise, evolutionists can cook the numbers from DNA comparisons to make it seem like our DNA is more similar to chimp DNA than it really is. The 98% number is very much like this.

The 98% number is not based on comparisons of the entire human genome (that is, all the DNA data for the human species) with the entire chimp genome (that is, all the DNA data for the chimpanzee species). No, it is based on comparing relatively limited sections of DNA, and looking only for one single type of genetic difference. If that particular difference isn’t present in those particular sections then Voila! The sections are declared to be identical! And a hasty generalization follows: the whole genome is declared to be 98% identical. “How amazing!” “How special!”

However, when other differences are accounted for, and more sections are compared with each other, you actually end up with much lower numbers. By some counts the similarity is as low as 86%.2 That is a seriously lower number because it doesn’t have as much “shock” power as the 98% figure that one hears tossed about so frequently.
But another reason to doubt the specialness of the human-chimp-DNA similarity is to compare it with other similarities. For instance, consider:

  • By one estimate dog DNA is 80% identical to human DNA.3
  • By another estimate zebrafish DNA is 85% identical to human DNA.4
  • By another estimate human DNA and chicken DNA are 60% identical. The same is true with fruit flies and bananas (they are both 60% identical to human DNA).5
  • Famously, Jonathan Marks has estimated that the DNA of daffodils (yes, the flowers) is 35% identical to human DNA.6

As you can see, the DNA of many other species is also very similar to ours. The similarity of human and chimp DNA, even when we make it into a percentage, is just not all that special. So the next time someone says, “Humans are 98% chimpanzee,” make sure you respond, “If you believe that, then we are also 85% zebrafish and 35% daffodil!” This high number used to be a hot commodity, but that was because of a hasty generalization. Now we know better. It is not all that special. It’s not like gold at all. It’s more like aluminum.

1. See and
6. Jonathan Marks, What It Means to Be 98% Chimpanzee (Berkeley, CA: University of California Press, 2002), 28-31. Marks says, “In the context of a 35% similarity to a daffodil, the 99.44% of the DNA of human to chimp doesn’t seem so remarkable. After all, humans are obviously a heck of a lot more similar to chimpanzees than to daffodils. More than that, to say that humans are over one-third daffodil is more ludicrous than profound. There are hardly any comparisons you can make to a daffodil in which humans are 33% similar” (29).

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