Do Genetic Studies Demonstrate Evolution?

by Stephen Caesar

Do Genetic Studies Demonstrate Evolution

Media reports claim that genetic studies of animals and humans demonstrate that groups of related species stem from a common ancestor. This appears to provide solid evidence for evolution, far beyond a few fossil fragments that can be interpreted several ways. An example of the confidence in genetics can be found in a statement by evolutionist Carl Zimmer in National Geographic:

"From generation to generation, certain genes of a species mutate at relatively steady rates. If you compare the genes of two species-say humans and chimpanzees-and you know the rates at which their genes have been mutating, you can estimate how long it has been since their ancestors diverged from a common ancestor" (2001a: 94).

However, media claims that geneticists have "seen" proof of evolutionary divergence in the distant past are biased and misleading. In truth, the allegedly visible evidence in the genetic record is not incontrovertible fact but simply inference based on assumptions. For example, Jonathan Losos, professor of biology at Washington University and director of that school's Tyson Research Center, writes:

"By comparing DNA sequences for the same gene or genes in different species, biologists can draw inferences about how species are related evolutionarily. Although controversy exists about the best method of deducing phylogenetic relationships from DNA comparisons, researchers agree that species that have more similar DNA are, in most cases, more closely related to each other than to another species whose DNA is less similar" (2001: 66 [emphasis added]).

Zimmer himself, despite his previous statement, has also shown that genetic mapping only provides inference for, not proof of, evolution. Instead of showing a clear map of how a given species evolved from a lower life-form, the genetic record shows a gigantic amount of genetic mutations that neither harm nor improve the species (called "neutral evolution"). Zimmer reports: "The irony [of this discovery] was inescapable: scientists finally had a chance to tune in to evolution on its most basic level, but the signal of natural selection seemed to be swamped by the static of neutral evolution" (2001b: 16).

Worse, the signs of evolution by natural selection, supposedly visible in the genetic record, are simply not there, so inferences have to be made, as Zimmer admits: "[R]esearchers can't go back millions of years to read a gene's ancestral sequence, nor can they know the precise history of mutations that led up to its current form. But biologists can make some inferences by comparing the genes of closely related animals.But the evidence from real genes is rarely so clean, and thus some uncertainty inevitably creeps in" (ibid. 18 [emphasis added]).

In an attempt to detect natural selection, Zihen Yang of University College, London, programmed computers to look at every possible mutation that genes could have made over the eons. Zimmer, however, points out the basic flaw in this system: "Yang examines each site in a gene and tries to predict its nucleotide on the basis of the rest of the gene's sequence as well as the sequence of the gene in related species. The computer makes a series of predictions based on different assumptions about the level of natural selection acting on the site and then picks the level that works best" (ibid. 19 [emphasis added]).

Thus, the science of genetics is no better at providing rock-solid proof of evolution than fossils. As with the fossil record, the genetic record does not unquestionably show species Y and Z evolving out of species X. Instead-again like the fossils-the genetic "evidence" is only speculation based on inference and pre-determined assumptions employed to reach a conclusion that evolutionists have already decided they're going to reach.


Losos, J. B. (2001). "Evolution: A Lizard's Tale." Scientific American 284, no. 3.

Zimmer, C. (2001a). "How Old Is It?" National Geographic 200, no. 3.

Zimmer, C. (2001b). "Tuning In." Natural History 110, no. 7.

Stephen Caesar is a graduate student in anthropology/archaeology at Harvard. He is the author of the e-book The Bible Encounters Modern Science, available at

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