It has long been claimed that humans and apes, and in particular chimpanzees, are close genetic cousins.
The American Museum of Natural History states that “humans and chimps share a surprising 98.8 percent of their DNA” and that the two species are “so similar because [they] are so closely related”, as they are “descended from a single ancestor species that lived six or seven million years ago”. The museum goes on to say that “human and chimp DNA is nearly identical when you compare the bands on chromosomes, the bundles of DNA inside nearly every cell.” 1
At first glance, this near-identical genetic similarity seems to provide ironclad evidence for common descent. However, while the 98.8% (the more commonly cited figure is 98.5%, so we will use that) figure is a staple of biology textbooks and popular media, recent genomic research suggests this statistic is far from accurate. When we look at the actual data, the “nearly identical” narrative begins to unravel.
Problems With The 98.5% Figure
The widely cited 98.5% figure is not a product of direct genomic comparison. It is a relic of the 1970s, established long before the genomes of humans and chimpanzees were sequenced (in 2003 and 2005 respectively). Scientists at the time used indirect methods such as observing the temperature at which hybrid human-chimpanzee DNA strand pairs dissociated, to arrive at their estimates. 2,3 The more heat energy required to pull them apart, the more similar the human and chimpanzee DNA strands were assumed to be.
Using this method, researchers estimated that human and chimpanzee DNA were about 98.5% similar. However, this was an indirect measurement, based mainly on regions of the genome that could hybridize easily. In other words, it focused on the regions of the human and chimpanzee genome that were already similar.
Yet even after the human and chimpanzee genomes were sequenced, some studies still reported the 98.5% figure. This is due to the methodology used — by looking only at the single nucleotide substitutions in alignable regions.
This methodology ignores several crucial types of genetic differences: indels, structural variations, and unalignable regions.3 By excluding these regions — especially the unalignable regions that are so different between humans and apes that they cannot be compared side by side — the methodology is essentially ignoring the most human parts of our DNA. This artificially inflates the genetic similarity between humans and chimpanzees.
Accounted For
- Single Nucleotide Variants (SNVs): one or a few nucleotides differ in parts of the genomes that align
Not Accounted For
- Insertions & Deletions (Indels): small sequences that are found in one genome but not the other.
- Structural Variation: Larger-scale rearrangements like inversions, translocations, as well as large-scale insertions and deletions, including copy number variants (CNVs). CNVs are regions where the number of copies of sequences vary among individuals.
- Unalignable Regions: Sections of DNA that are so different that they cannot be aligned or compared side by side at all.
Types of Genetic Variation 4
A More Accurate Comparison
Fortunately, in recent years, there have been great advancements in genomic sequencing technology.
- 2001: First draft of the human genome was published.
- 2003: The human genome was 92% sequenced and finalized under the Human Genome Project. About 8% of repetitive regions in the genome remained unsequenced due to technological limitations.
- 2005: The chimpanzee genome used the human genome as a reference and was incompletely sequenced,
- 2022: A breakthrough was achieved and the entire human genome was completely sequenced.5
- 2025: Ape genomes, including the chimpanzee genome, were finally completely sequenced, telomere to telomere without using the human genome as a reference.
Armed with fully sequenced genomes and better methodology, recent scientific studies have finally moved away from the inaccurate 98.5% figure, revealing a human-chimpanzee genetic gap that is significantly wider than previously believed.
- Britten (2002): 95% Similarity 3
One of the earliest serious attempts to directly quantify human–chimpanzee genome similarity using proper methodology came from molecular biologist Roy J. Britten in 2002. He compared five bacterial artificial chromosomes from the chimpanzee genome with the human genome. A limitation was that the length of the DNA compared was a tiny fraction of the entire chimpanzee genome, as the Genome Project was still ongoing at that time.
Britten’s widely cited paper stated that the old 98.5% figure was “probably in error.” He concluded that a more accurate estimate for the specific DNA he was able to compare was around 95% similarity. Single-nucleotide substitutions accounted for a 1.4% difference, while the inclusion of indels added another 3.4% of additional divergence.
Crucially, this 95% figure only applied to the DNA that could be aligned. Britten noted that there may be large gaps that were missed as part of chimpanzee BAC sequences that could not be aligned with the human genome. If the unalignable regions were included, the genetic similarity could drop even further.
Despite these limitations, Britten’s work was a critical first step in demonstrating that the genetic similarity between human and chimpanzees is lower than the widely purported 98.5% figure.
- Yoo et al. (2025): 85% Similarity 6
In 2025, a landmark study titled “Complete sequencing of ape genomes” fully sequenced the genomes of six ape species (including chimpanzees) for the first time. This, together with the fully sequenced human genome in 2022, finally allowed for a full comparison between the two genomes. Their results were published in the prestigious journal Nature.
Here is what they found: “sequence comparisons […] revealed greater divergence than previously estimated”. While the single-nucleotide variant (SNV) percentage was indeed around 1.5-1.6%, there was an additional gap divergence of 12.5-13.3% between the ape and human genomes, as a result of indels, structural variants and unalignable regions.
Once the massive gap divergence is factored in, the total genetic similarity between human and chimpanzee DNA drops to around 85% 7, which is ten times larger than commonly portrayed.
Counterargument: Intraspecies Gap Divergence Is Huge too
In response, some evolutionists counter that the same graph in Yoo’s study shows that there is a 13.8% gap divergence just among gorillas alone (GorGor1). Their argument goes like this: since the gap divergence between humans and chimpanzees is about the same as the gap divergence between any two gorillas, and no one believes that every gorilla is its own species, gap divergence is not a meaningful measure of the relatedness of two genomes. If the 14% gap divergence among gorillas is just noise, then the 15% gap divergence between humans and chimpanzees should also be considered noise. 8
Noise Vs. Meaningful Difference
However, this argument ignores the source of the divergence. Not all differences are the same. It is crucial to differentiate between noise and meaningful difference.
The massive variation in gorillas is primarily driven by subterminal heterochromatic caps—large blocks of repetitive satellite DNA at the ends of chromosomes that can contract or expand. This causes their sizes to vary wildly from one gorilla to another. These caps make up 8.5% of the total gorilla genome 9 and are a large contributor to the 13.8% gap divergence. In fact, Yoo’s paper makes it clear that satellites (in general, not just at the subterminal heterochromatic caps) “accounted for the largest repeat variation […] 13.0% in gorillas (462.5 Mb in total)”. 6
In fact, there is a direct correlation between the amount of subterminal heterochromatic caps and the intraspecies gap divergence, as shown in the table below. The chimpanzee genome possesses fewer of these structures (5.4% of the genome) so chimpanzee intraspecies gap divergence is lower as well, at 8.1%.
In humans, the subterminal heterochromatic caps are completely absent. This is why the human intraspecies gap divergence is only 3.5%. This number is in line with what the Human Pangenome Reference Consortium found: on average, pairwise human genome comparisons show about 136 Mb (4.4%) of divergence.10
Therefore, while a gorilla’s 13.8% difference might be dismissed as “noise” due to these volatile, repetitive satellite DNA, the 15% difference between humans and chimps cannot be dismissed in the same way. The human genome is structurally “clean”, making the gap between us and chimpanzees a matter of meaningful difference, not just repetitive padding.
Using an analogy, two gorillas are like two sentences which are identical. The only difference is that the second sentence has extra full stops that add length but no new information. If you count every character, the sentences look about 13.8% different. Yet, the meaningful content is the same in both sentences.
Non-Meaningful Difference
Gorilla 1: This is a sentence about gorillas doing nothing..
Gorilla 2: This is a sentence about gorillas doing nothing……….
On the other hand, the difference between humans and chimpanzees is fundamentally different. The human “sentence” does not have the extra full stops, yet it is still different from the chimpanzee “sentence”. It boils down to actual differences in the content.
Meaningful Difference
Chimpanzee: This is a sentence about chimpanzees eating bananas…
Human: This is a sentence about humans who can walk and talk.
How Human and Chimpanzee Genomes Differ
- Humans have 46 chromosomes, whereas chimpanzees have 48
- Total divergence between the human and chimpanzee genomes is 15%
- The 15% of the human genome that is not found in chimpanzees includes 185 human-specific gene families, which potentially hold the explanation for our intellectual capacity. Three such gene families, namely NOTCH2NL, SRGAP2C, and ARHGAP11, have been connected to the expansion of the frontal cortex of the human brain.6
The researchers also found a Pterv1 virus sequence that is present in all African great apes, but is not found in humans.6 This contradicts the evolutionary story. If humans and chimpanzees have a closer evolutionary relationship and supposedly share a common ancestor after diverging from the gorilla lineage, then why do gorillas and chimpanzees have the Pterv1 virus sequence, but humans do not?11
The proposed evolutionary tree for humans and great apes hinges on two lines of argument: anatomical similarities (homology) and genetic similarities. Anatomical similarities by themselves are a relatively weak argument.
Hence, a small genetic difference of 1.5% has been used as the strongest proof for human-chimpanzee common ancestry for decades. Yet now, this figure has been shown to be inaccurate. The tenfold increase from a 1.5% difference to a 15% difference is not just a statistical adjustment. It is a massive biological discontinuity that evolution has a hard time explaining. Evolutionists need the 1.5% figure to be true or the narrative of humans being slightly evolved versions of apes simply falls apart.
This is the reason why the 98.5% myth has persisted in popular culture for decades, despite it not being factual. It also shows how “sticky” a narrative can be, even when the underlying data has moved on.
How Do We Understand the 85% Similarity
In an earlier post, we noted that similarities can be due to common design just as much as they can be due to common descent. This is because all mammals need to perform the same core biological functions like eating, breathing, and reproducing. From a design perspective, it makes sense for the Creator to simply use a common molecular toolkit.
Yet it is in the 15% difference that our defining human traits reside: our capacity for language, abstract reasoning, morality, and worship. Humans alone write books, compose music, tell stories, form governments, and ask questions like “Why am I here?” and “Is there a God?” No other species does this, not even chimpanzees. These are features found only in humans, not because we are slightly more advanced animals, but because we are qualitatively different from them.
Can Chimpanzees Learn Language?
If humans and chimpanzees have a high degree of genetic similarity, then it is logical to expect chimpanzees to have at least a rudimentary capacity for language. However, because the 98.5% similarity is a product of incomplete and cherry-picked data rather than biological reality, scientists who set out with this premise were left chasing a mirage.
A well-known example is that of Nim Chimpsky. In the 1970s, psychologist Herbert S. Terrace set out to challenge the idea that language is unique to humans by teaching a chimpanzee named Nim Chimpsky American Sign Language. Raised in a human-like environment, Nim was taught over a hundred signs and could combine them into short sequences like “Nim eat banana.” For a time, the project seemed promising.
However, after reviewing thousands of videotaped sessions, Terrace was forced to draw a different conclusion. Nim’s use of signs was largely imitative, reward-driven, and often subconsciously prompted by the human trainer. It can communicate its basic needs, but it could not understand grammar, syntax, nor abstract concepts. It also did not construct any original sentence. Unlike human children, it has never asked, “Why?” Ultimately, apes just could not acquire language.12
Conclusion
The 98.5% myth has persisted because it fits a specific evolutionary narrative. However, clinging to an inaccurate estimate when modern genomic sequencing shows a 15% difference is a disservice to the public. If the data shows that humans are quantitatively and qualitatively distinct, withholding that information prevents us from appreciating the complexity of our genome and distorts how we view human dignity, morality, and our place in the universe.
It stops us from asking what makes us unique, or to take it a step further, who made us unique. Maybe once we stop trying to find our identity in the zoo, we can finally start finding it in the stars — in the One who made us in His image.
References
1 DNA: Comparing Humans and Chimps. (n.d.). American Museum of Natural History. https://www.amnh.org/exhibitions/permanent/human-origins/understanding-our-past/dna-comparing-humans-and-chimps
2 Cohen, J., Relative differences: the myth of 1%, Science 316:1836, 2007. https://www.science.org/doi/10.1126/science.316.5833.1836
3 Britten R. J. (2002). Divergence between samples of chimpanzee and human DNA sequences is 5%, counting indels. Proceedings of the National Academy of Sciences of the United States of America, 99(21), 13633–13635. https://doi.org/10.1073/pnas.172510699
4 Hotspots of Human Mutation – Scientific Figure on ResearchGate. https://www.researchgate.net/figure/Types-of-Genetic-Variation-Single-nucleotide-variants-SNVs-and-indels-are-changes-that_fig1_346898467
5 First complete sequence of a human genome. (2022, April 12). National Institutes of Health (NIH). https://www.nih.gov/news-events/nih-research-matters/first-complete-sequence-human-genome#:~:text=The%20Human%20Genome%20Project%20%2C%20completed,longer%20sequences%20without%20compromising%20accuracy
6 Yoo et al. (2025). Complete sequencing of ape genomes. Nature, 641, 401–418. https://doi.org/10.1038/s41586-025-08816-3
7 Calculated by taking 13.3% gap divergence (using human as the base) + [1.6% SNV divergence (using human as the base) * 86.7% alignable region] = 14.7% total divergence between the autosomes of humans and chimpanzees. The same method produces a 13.8% total divergence when chimpanzees are used as the base. This is because the genomes of chimpanzees and humans are slightly different in size.
8 Lents, N. H. (2025, October). How similar are human and chimp genomes, really? Quantifying genetic difference isn’t straightforward. Free Inquiry. https://secularhumanism.org/2025/09/how-similar-are-human-and-chimp-genomes-really-quantifying-genetic-difference-isnt-straightforward/
9 Yoo D, Munson KM, Eichler EE. (2026). Epigenetic and evolutionary features of ape subterminal heterochromatin. Genome Research, 36(1), 38-49. doi: 10.1101/gr.280987.125.
10 Liao, WW., Asri, M., Ebler, J. et al. (2023). A draft human pangenome reference. Nature, 617, 312–324. https://doi.org/10.1038/s41586-023-05896-x
11 A common rebuttal is the independent infection theory. Some evolutionists argue that after the human lineage diverged, a Pterv1 infection swept through the African Great Apes but simply missed the human line. Another theory is that the infection occurred in the common ancestor of all three, but humans successfully purged the sequence through natural selection. While both are theoretical possibilities, they introduce significant complexity to the model. Both require a double-event explanation (either two separate infections or an infection followed by a perfectly clean deletion in humans). Additionally, given that these sequences often land in regions where there is little selective pressure to remove them, a total removal leaving no trace is statistically improbable.
12 Terrace, H. S. (2019, October 2). Why Chimpanzees Can’t Learn Language: 1. Psychology Today. https://www.psychologytoday.com/sg/blog/the-origin-words/201910/why-chimpanzees-cant-learn-language-1