Editor’s note: Dr. Casey Luskin broke the bombshell story last week that, according to data in a new paper in the journal Nature, the human and chimpanzee genomes are not a mere 1 percent different, as you so often hear from science media and science educators, but more like 15 percent different. What we’ve called at Evolution News the “1 percent myth” (see the series here) is thus an icon of evolution that has dramatically tumbled. The story had to be “broken” by us because the editors at Nature had chosen to bury the relevant information (why?) under mounds of arcane technical jargon in the paper’s Supplemental Data section. Unfortunately, the 1 percent myth is promulgated as fact at, among other places, the nation’s own Smithsonian Institution. Dr. Luskin today sent this letter to three influential people at the Smithsonian’s National Museum of Natural History — Dr. Kirk Johnson (Sant Director, National Museum of Natural History), Dr. Lonnie G. Bunch II (Secretary, Smithsonian Institution), and Kate Forester (Deputy Chief of Staff to the Smithsonian Board of Regents) — complete with photos of the relevant signage.

May 27, 2025

To: [Various Recipients]
Smithsonian Institution

From:
Casey Luskin
Associate Director, Center for Science and Culture
Discovery Institute
208 Columbia Street
Seattle, WA 98104

Dear Smithsonian National Museum of Natural History,

My name is Casey Luskin and I hold a PhD in Geology from the University of Johannesburg, an MS degree in Earth Sciences from the University of California at San Diego, a law degree (JD) from the University of San Diego, and have been a California-licensed attorney since 2005. Professionally, I direct the Intelligent Design 3.0 Research Program at Discovery Institute, where I serve as Associate Director for the Center for Science and Culture. 

I’m writing to request corrections to statements at the Human Origins exhibit (“Exhibit”) at the Smithsonian Institution’s National Museum of Natural History (“NMNH”) about the degree of genetic difference between humans and apes which are no longer scientifically accurate. As seen in Attachments A, B, and C below, the Exhibit asserts the following statements as fact:

• Humans and chimpanzees are “98.8% genetically similar,”
• Humans and gorillas are “98.4% genetically similar,”
• Humans and orangutans are “96.9% genetically similar.”

According to data reported in a scientific paper, Yoo et al. (2025) recently published in Nature,¹ these statistics are scientifically false. This paper presented for the first time “complete,” de novo, updated, telomere-to-telomere sequences of the genomes of various ape species. These “complete” genome drafts are vastly improved over previous drafts of ape genomes. Yoo et al. (2025) is thus able to provide much improved calculations of the actual degrees of genetic difference between human and ape genomes at a level of comprehensiveness and accuracy that has been previously unavailable.

In short, human-chimpanzee genetic differences reported in Yoo et al. (2025) are at least an order of magnitude greater than what is currently stated at the Exhibit. If the Exhibit is to avoid miseducating the public, then it must be corrected to reflect the scientific reality. Below is a brief discussion of the findings of Yoo et al. (2025), which are elaborated at EvolutionNews.org.²

Yoo et al. (2025) calculates the “gap-divergence”³ — i.e., the minimum genetic difference based upon portions of one genome that could not be aligned to the other genome — between humans and chimpanzees, gorillas, and orangutans, to be the following: 

• Sumatran Orangutan (Pongo abelii) vs Human: 15.4 percent to 16.5 percent “gap-divergence” (i.e., minimum genetic difference).
• Gorilla (Gorilla gorilla) vs Human: 17.9 percent to 27.3 percent “gap-divergence” (i.e., minimum genetic difference).
• Chimpanzee (Pan troglodytes) vs Human: 12.5 percent to 13.3 percent “gap-divergence” (i.e., minimum genetic difference).

Using its improved ape genomes, the paper further reports another type of genetic difference — the single nucleotide variation (SNV) in alignable portions of the genome — to be the following: 

• Sumatran Orangutan (Pongo abelii) vs Human: ~3.6 percent different
• Gorilla (Gorilla gorilla) vs Human: 1.9 percent – 2.0 percent different
• Chimpanzee (Pan troglodytes) vs Human: 1.5 percent – 1.6 percent different

If we add the gap-divergence to the SNV differences, then the data reported in Yoo et al. (2025) indicate the following total percents of genetic difference between human and ape genomes: 

• Sumatran Orangutan (Pongo abelii) vs Human: ~19 percent – 20.1 percent different
• Gorilla (Gorilla gorilla) vs Human: ~19.8 percent – 29.3 percent different
• Chimpanzee (Pan troglodytes) (target) vs. Human: ~14.0 percent – 14.9 percent different⁴

As seen in the table below, these numbers are far greater than what is currently stated at the Exhibit. In the cases of human vs. chimpanzee or human vs. gorilla, the actual percentages of genetic difference reported by Yoo et al. (2025) are greater by more than an order of magnitude compared to the Exhibit:

Another method outlined in the Supplementary Data of Yoo et al. (2025), a Progressive Cactus alignment, reports similar numbers. According to that method, only 84.95 percent of the nucleotides in the chimpanzee genome had an identical 1:1 correspondence with the human genome (haploid autosome analysis), effectively a difference of 15.05 percent. For the full genome diploid autosome analysis, human-chimpanzee genetic differences reported by this method grew to 16.11 percent. (Under this method the human and chimp X chromosomes showed a difference of 20.12 percent, and the human and chimp Y chromosomes a difference of 95.68 percent!) The point is this: Multiple analysis methods from Yoo et al. (2025) show that the human and chimpanzee genomes are about 14.0 percent to 16.1 percent different. One could summarize this data as indicating that the human and chimpanzee genomes are approximately 15 percent different.

I urge you to correct the Exhibit to reflect more current, accurate scientific data. The NMNH is the nation’s premiere science museum, and it would be inexcusable for the museum to present scientifically inaccurate data about human genetic similarity to apes to the public. To fail to correct this data is to use taxpayer money to miseducate the public about a question of profound scientific, sociological, and philosophical interest. 

Unfortunately, there are other statements which also require correction in light of this new data. As seen in Attachment D, the Exhibit states:

• “There is only about a 1.2 percent genetic difference between modern humans and chimpanzees throughout much of their genetic code.”

This statement is extremely misleading to the point of being false. It leaves the average reader with the false impression that there is only “1.2 percent genetic difference between modern humans and chimpanzees…” This needs to be changed to reflect the data reported in Yoo et al. (2025) which indicate approximately a 15 percent genetic difference between modern humans and chimpanzees. 

Moreover, by including the ambiguous term “much,” this statement essentially becomes a meaningless and unfalsifiable truism. On a scientific level, the statement is incoherent because the reader is left totally unclear on exactly how “much” of the human genome is 1.2 percent similar to chimpanzee, and to what extent other portions of the two genomes may be quite different. A more accurate, meaningful, and objective statement would read: 

• “There is approximately a 15 percent genetic difference between modern humans and chimpanzees throughout their genetic code.”

However, if the NMNH were to adopt this change, some might feel that it undermines the previous sentences at the Exhibit, which, as seen in Attachment D, state:

• “DNA evidence … confirms that … modern humans and chimpanzees diverged from a common ancestor between 8 and 6 million years ago.” 

This, of course, is a statement based upon molecular clock calculations which assume (a) that point mutations accumulate randomly, at a constant rate over time in the two genomes, and (b) that the differences between the genomes are always the result of random mutations and never the result of intelligent design of the genomes of those two species. 

At the very least, those two assumptions should be disclosed at the Exhibit. And if those assumptions cannot be justified, then the Exhibit has no business claiming that “DNA evidence … confirms that … modern humans and chimpanzees diverged from a common ancestor between 8 and 6 million years ago.” 

I look forward to hearing your response to my concerns and seeing changes made to the Exhibit. Thank you for your time and attention to this letter.

Sincerely,

Casey Luskin

Attachment A:

Photo of NMNH Human Origins exhibit taken August 2023:

Attachment B:

Photo of NMNH Human Origins exhibit taken May 2025:

Attachment C:

Photo of NMNH Human Origins exhibit taken May 2025:

Attachment D:

Photo of NMNH Human Origins exhibit taken May 2025:

Notes

1. Yoo et al., “Complete sequencing of ape genomes,” Nature, 641: 401-418 (May 8, 2025).
2. See Casey Luskin, “Fact Check: New ‘Complete’ Chimp Genome Shows 14.9 Percent Difference from Human Genome,” Evolution News (May 21, 2025), https://evolutionnews.org/2025/05/fact-check-new-complete-chimp-genome-shows-14-9-percent-difference-from-human-genome/
3. Yoo et al. (2025) defines the “gap-divergence” as follows: “Gap divergence is defined as the fraction of positions in the target haplotype that are not aligned to the other haplotype, which could be due to biological processes (e.g., gene loss/gain and insertions/deletions), missing data, or technical problems (e.g., alignment failure due to SVs, repetitive elements, etc.).”
4. The larger number, 14.9 percent, is arguably more relevant here, since this reflects how similar the whole human genome assembly is to the chimpanzee genome.
5. This figure is the percent increase needed to change the Smithsonian’s claimed degree of genetic difference between these species to the lowest actual degree of genetic difference reported by Yoo et al. (2025). 

[Letter Updated May 28, 2025 to correct a slight miscalculation in the original figures in column 4 of the table, which did not affect any of the other statistics and numbers cited in the letter. The updated figures have been sent to the Smithsonian.]