Genetic Entropy

John C. Sanford is a plant geneticist who spent his career at Cornell University and co-invented the gene gun, a technique for introducing DNA into plant cells that is now widely used in agricultural biotechnology. He was not a creationist for most of his career. He became one, and in 2005 he published Genetic Entropy and the Mystery of the Genome, which makes an argument that he says he could not escape after years of working with the genetics of living populations: the human genome is accumulating mutations faster than natural selection can eliminate them, and this means that the genome is deteriorating — slowly, generation by generation — rather than improving. If he is right, this is a fundamental problem for the Darwinian model, which requires that random mutations sorted by natural selection can produce ever-more-complex and functional genomes over long periods of time. Sanford argues that the observable direction of genomic change is the opposite.

The argument: mutation rate vs. selection pressure

The core of Sanford's argument is a mathematical problem for natural selection. The human genome contains approximately 3 billion base pairs. Each human generation introduces a large number of new mutations — estimates range from 50 to 200 new mutations per individual per generation, most of them in non-coding regions but some affecting functional genes. The question is: what happens to these mutations over time?

Natural selection eliminates mutations that dramatically reduce fitness — a lethal mutation kills the organism before it reproduces and does not pass on. But the overwhelming majority of mutations are not lethal; they are slightly deleterious, reducing fitness by a very small amount. These mutations are invisible to selection: natural selection cannot distinguish between an organism with a mutation that reduces fitness by 0.01% and a normal organism. These mutations therefore accumulate freely, generation by generation, producing what population geneticists call mutational load.

Sanford's argument is that this load is not trivial. When you sum up thousands of slightly deleterious mutations accumulating over many generations, the cumulative effect on fitness is real and measurable — and it moves in the wrong direction. Instead of the genome gradually improving toward better-adapted organisms (as evolution requires), the genome is gradually degrading. He calls this "genetic entropy" by analogy with thermodynamic entropy: just as the second law of thermodynamics describes the tendency of physical systems toward disorder, genetic entropy describes the tendency of the genome toward increasing dysfunction.

The evidence Sanford cites

Sanford cites several lines of evidence for his argument:

Population genetics models. Computer simulations of mutational accumulation in large populations — including the "Mendel's Accountant" simulation developed by Sanford and colleagues — show that when realistic parameters are used (realistic mutation rates, realistic fitness effects per mutation, realistic selection coefficients), populations do not improve over time; they accumulate damage. Sanford argues that the only way to get improvement in these models is to assume mutation rates and fitness effects that don't correspond to what is observed in real populations.

Ancient DNA studies. Studies of ancient DNA extracted from human remains suggest that the oldest human genomes show fewer deleterious variants than modern genomes — consistent with a pattern of accumulating damage over time rather than improving over time.

Declining human health markers. Sanford notes that many markers of physical fitness (bone density, certain immune functions) appear to be declining in human populations over recorded history, though he acknowledges this is difficult to isolate from environmental and dietary changes.

The mainstream response

Population geneticists have responded to Sanford's argument on several fronts:

Purifying selection is more powerful than Sanford models. Even small fitness differences compound over many generations. A mutation that reduces fitness by only 0.01% will still be eliminated by selection over sufficient time — the process is slow but not absent. Selection at the population level, combined with reproductive variance, can cull slightly deleterious mutations more effectively than Sanford's models suggest.

Most of the genome is not functional. The mainstream view is that only a small fraction of the human genome (estimates range from 8% to 20%) is under functional constraint. Mutations in the non-functional portions have no fitness consequence and do not contribute to genetic entropy. Sanford's calculation of mutational load depends on a higher percentage of functional genome than most evolutionary geneticists accept.

Sanford's simulations use cherry-picked parameters. Critics argue that "Mendel's Accountant" and similar simulations are built with assumptions that make degradation more likely — particularly around the distribution of fitness effects for mutations. When more mainstream parameter estimates are used, the degradation is much smaller or absent.

Ancient DNA evidence is ambiguous. The interpretation of ancient DNA comparisons is complicated by sampling bias, the difficulty of distinguishing deleterious from neutral variants, and the fact that the oldest ancient genomes come from populations that are not ancestral to modern humans in straightforward ways.

The honest verdict

Sanford raised a real issue in population genetics: the problem of nearly neutral mutations and their accumulation is genuinely debated in the technical literature, not just by creationists. The population geneticist Alexey Kondrashov, a mainstream evolutionist, published work in the 1990s on the problem of "mutational meltdown" in small populations, and the field takes the question seriously. The existence of synergistic epistasis — where mutations interact to cause more damage than each would alone — is one mechanism evolutionists propose to prevent the accumulation Sanford describes.

Where the disagreement lies is in the quantitative parameters: how many mutations per generation, what fraction affect fitness, how strong is purifying selection, how common is synergistic epistasis. These are empirical questions with contested data, and the mainstream consensus is that Sanford's parameters are not representative of what is observed.

The honest assessment: Sanford identified a real vulnerability in naive Darwinian optimism — the genome does not simply improve over time, and the selection-versus-accumulation balance is a real mathematical constraint. Whether this constraint is sufficient to falsify the evolutionary account of human origins is a much stronger claim, and the mainstream scientific community's answer is that it is not, because they dispute the parameters. Neither answer is settled beyond dispute, and the site says so.

For the Christian, the argument gains its force from a direction other than the technical genetics. The pattern in Scripture is not of creation improving on its own power but of a creation that suffers under the consequences of the fall, groaning and awaiting redemption (Romans 8:22). Whether the genome is slowly deteriorating is, in that framework, exactly what one might expect — not from a God who designed things to improve themselves without Him, but from a creation that is "subjected to vanity" (Romans 8:20) and awaiting the restoration of all things. The genetic entropy argument, if it holds, is consistent with that picture. It is not, by itself, proof of it.

Related: DNA and the Question of Information, Irreducible Complexity, Macroevolution and the Fossil Record, The Origin of Life, Did We Come From Apes? Primary source: John Sanford, Genetic Entropy and the Mystery of the Genome (FMS Publications, 2005, 4th ed. 2014). Counter-arguments drawn from mainstream population genetics literature; synergistic epistasis literature: Kondrashov (1988, 1994).