Endogenous Retroviruses: A Powerful Proof of Evolution

Endogenous retroviruses (ERVs) are remnants of ancient viral infections that have been passed down through generations. When a retrovirus infects a reproductive cell, its genetic material can become permanently embedded in the DNA of the host and be inherited by its offspring. Over millions of years, these viral sequences accumulate in the genome and serve as markers of shared ancestry between species.

One remarkable fact about ERVs is that they integrate into the genome at random locations. The odds of the same virus independently inserting itself into the exact same location (locus) in two different species is astronomically low. Studies suggest that the probability of a virus inserting itself into the same locus twice by chance is approximately 1 in 10⁴⁵ (one in one followed by forty-five zeros) (Sverdlov 399).

Humans and chimpanzees share at least 16 ERVs in the exact same locations within their genomes. The probability of this happening by chance is roughly 1 in 10⁷²⁰ (one in one followed by seven hundred twenty zeros) (Sverdlov 400). To put this into perspective, scientists estimate that the entire observable universe contains about 10⁸⁰ (one in one followed by eighty zeros) stars (Eddington 242). This means the odds of these ERVs appearing in the same location by chance is far smaller than the total number of stars in the universe.

ERVs are powerful evidence that humans and chimpanzees share a common ancestor. These genetic markers are not only identical in sequence but also appear in the same locations, something that random chance simply cannot explain. Evolutionary science provides the best explanation for this phenomenon, reinforcing the deep genetic connections between all life on Earth.

Works Cited

Eddington, Arthur S. The Nature of the Physical World. Macmillan, 1928.

Sverdlov, Eugene D. "Retroviruses and Primate Evolution." BioEssays, vol. 22, no. 2, 2000, pp. 161–171.