Genetic Entropy is a hypothesis in population genetics that proposes genomes inevitably accumulate harmful mutations over time, leading to a gradual, unavoidable decline in biological fitness—even in the presence of natural selection. The concept is most strongly associated with Dr. John C. Sanford, a former Cornell University geneticist, and is often discussed in creationist and intelligent design literature.
1. Core Idea of Genetic Entropy
Genetic entropy argues that most mutations are slightly deleterious, but too small for natural selection to detect, and therefore accumulate over generations, degrading the genome. This accumulation supposedly leads to reduced fitness, increased genetic load, and eventual population collapse or extinction
The term “entropy” is borrowed from thermodynamics to suggest irreversible informational decay in DNA. This fits perfectly because mutations occur due to random changes in a genetic sequence, and thermodynamic entropy is largely the result of randomness, such as the motion of heat in thermodynamic systems. It is the logical conclusion of design, because a designed genetic code would start perfect, and any random changes tend to be harmful, eventually leading to complete collapse. This can be demonstrated with a computer program, where random changes are made to the computer's memory; such a program always results in the computer crashing.
In the case of genetics, evolutionists need to maintain viability over billions of years, while producing gradual improvement. However, when viewed from a design perspective, genetic entropy makes a lot of sense, simply because you are making random changes in what was originally a perfect system.
2. Key Assumptions of the Model
Genetic entropy relies on several foundational assumptions: most harmfulness of mutations, selection Limits, mutation rate, and finite genome integrity. When genetics is examined from a design perspective, all these assumptions make perfect sense; they are based on observation rather than theoretical necessity or philosophical presumption. Universal common descent, on the other hand, has to assume the exact opposite, regardless of what the evidence says, because it cannot work otherwise
Most mutations are harmful (not neutral or beneficial), while beneficial mutations are extremely rare and too weak to compensate for the accumulation of harmful ones. It needs to be noted at this point that neutral, harmful, and beneficial are frequently defined by evolutionists relative to the organism's specific environment. In genetic entropy, harmful, neutral, and beneficial are seen in more absolute terms. You can have a mutation that is beneficial within a specific environment, but generally harmful to the organism because it does not do as good a job as the original version. This results in an organism that is well adapted to its environment, while being objectively less fit. For example, it may be ideally suited for the environment in which it lives, but in general, it does not live as long as the original variety.
Genetic entropy suggests that natural selection is rather limited in its effectiveness. Specifically, it is effective only against strongly deleterious mutations and cannot “see” mildly deleterious mutations (selection coefficient very close to zero). The main reason for this is that for a selection process to be very effective, it needs an intended goal. For example, artificial selection (Selective breeding) is a very strong selection process because the person doing the breeding has a specific result they are trying to achieve in the animals they are breeding. Natural selection, on the other hand, is admitted by evolutionists to have no actual goals. This, along with observation, indicates that natural selection is really only good at helping organisms to adapt to changes in the environment. This means that it will not filter out any mutations that are mildly harmful in general, but neutral or even beneficial within that particular environment. Pretty much, if it is not a bad enough mutation to kill an organism possessing it before it can reproduce, natural selection may not catch it, and in fact, actually help it if it is beneficial in that particular environment.
Real-world mutation rates are too high for selection to remove all harmful mutations; as a result, each generation adds more damage than selection can remove. Direct measurements of mutation rates show that, on average, each generation adds about 100 mutations to the genome. Unless most of them are entirely neutral, they will do damage over time as the number accumulates. The idea that most mutations are entirely neutral is based on two ideas. The first is the totally debunked notion of junk DNA, where most of our DNA does absolutely nothing; as a result, it can mutate all at once without hurting us. The second is that mutations are only beneficial, harmful, or neutral relative to their environment. If there exists any absolute measure of beneficial, harmful, or neutral, then the overwhelming majority of mutations will be harmful in some way because they are random. This is the case even if they happen to provide a benefit in a particular environment.
A finite genome integrity results because genomes are highly optimized, and therefore any random change is more likely to disrupt than improve function. This is a natural consequence of looking at the genome from a design perspective. The designer of any type of code would make that code as perfect as possible. As a result, the genomes of each kind would have started perfect, and random mutations by definition would be deleterious to at least some degree and in some fashion. This is simply a logical conclusion of starting with a designed genome. Once again, for universal common descent to be even possible, let alone true, genomes would have to have the potential of infinite integrity. Otherwise, it would not only be impossible to go from bacteria to man, but also for the process to be able to even continue for millions of years.
3. How Genetic Entropy Works
New mutations occur with each individual receiving about 60 to 100 new mutations per generation. This is the measured rate for humans. Most mutations are slightly harmful but too small to cause immediate problems. Natural selection removes only the worst mutations, but mildly deleterious ones persist. Mutations accumulate across generations, causing an overall fitness decline. Increasing health issues, producing increased infertility, and reducing survivability. The long-term outcome is species extinction unless intervention occurs. Sanford argues this process is inevitable and irreversible.
One factor that needs to be kept in mind is that, when discussing mutations as harmful, we are referring to harm in an absolute sense. Not relative to the environment and not relative to natural selection. Very often, when evolutionists discuss beneficial, neutral, and harmful mutations, it is in relation to either the environment or natural selection. However, it is possible to have a mutation that is beneficial or neutral in a given environment but still causes a slight bit of harm that natural selection cannot detect. The situation we are talking about is where a mutation weakens the organism in some general way relative to its parents but may provide a survival advantage within a particular environment.
A good example of this is the loss of the ability of a polar bear to produce pigment in its hair. The reason this qualifies as harmful is that it represents a loss of genetic information. It simply occurred in a part of the body that does not cause physical harm; however, it has a survival advantage in arctic regions because it gives polar bears good camouflage in a snowy environment. If you tried putting a black or brown beer in Alaska, they would probably not do very well because they would stand out like a sore thumb to both their prey and any enemies that they have. On the flip side, a polar bear would stand out like a sore thumb in a wooded area.
The point is that when discussing whether or not a mutation is harmful, neutral, or beneficial, you have to consider the context. The simple fact of the matter is that a mutation can have a survival advantage in a particular environment, yet be generally harmful to the organism in terms of general fitness
4. Genetic Entropy vs. Classical Evolutionary Theory
Here we have a comparison between Genetic Entropy and Classical Evolutionary Theory on five different topics. We will then look at which view on the topic is more in accordance with reality, in which one is merely a theoretical necessity, and wordplay.
On the effects of mutations, Genetic Entropy says that mutations are mostly harmful, but Evolutionary Theory says that they are mostly neutral. From the standpoint of evolutionary theory, having mutations mostly neutral is a theoretical necessity because we need to have more than a billion years' worth of ancestry for it to work. This idea also extends from the falsified idea of junk DNA, along with making neutrality relative to the environment and natural selection. Genetic entropy theory, on the other hand Is looking at mutations in a more absolute sense, seeing random changes in an originally perfect genetic code as inevitably harmful.
With regards to beneficial mutations, genetic entropy sees them as extremely rare, while evolutionary theory sees them as rare but significant. The problem here is that evolutionary theory needs lots of beneficial mutations to go from bacteria to man and every other multicellular organism on Earth. Furthermore, they are judging benefit relative to the environment that the Organism lives in and not in any absolute sense. Genetic entropy proponents, on the other hand, recognize the fact that a mutation can have a benefit in a particular environment while being generally harmful to the organism, such as reducing its overall strength and vitality in a small way.
Genetic entropy sees natural selection as generally weak because it has no specific goal. In fact, the closest thing it has to a goal is helping populations of organisms adapt to changes in their environment. This makes it way too weak to filter out small but slightly harmful mutations, which then add up over time. Evolutionary theory, on the other hand, requires, without any real evidence, that natural selection is not only capable of preventing genomic collapse, but also creating the many gigabytes of new complex specific information necessary to produce all living things on earth from a common ancestor.
Genetic entropy sees the long-term prognosis of every genome on earth to be decay over time, while evolutionary theory sees nothing more than adaptation and diversification. You have to understand, however, that genetic entropy also sees adaptation and diversification, but it simply sees it in the context of genetic decay. Evolutionary theory, on the other hand, cannot allow this process to go beyond including overall genetic decay simply because it needs species and their lines of descendants to last millions and even billions of years.
Finally, concerning the survival of species, genetic entropy sees it as only temporary as a result of an accumulation of random, slightly harmful changes. Evolutionary theory, on the other hand, needs stability over geological time periods, not only for individual species, because they see some as lasting millions of years, but for their descendants as well, because these lines need to last Hundreds of millions to billions of years.
5. Evidence Cited by Proponents
Here are three lines of evidence frequently cited as supporting genetic entropy. They are not the only lines of evidence, but they are the most frequently used while providing good illustrations at the same time.
The concept of human genetic load describes the accumulation of deleterious mutations within the gene pool, a phenomenon increasingly influenced by the unique demographic and environmental shifts of modern societies. In contemporary populations, the relaxation of natural selection—driven by advancements in medicine, sanitation, and nutrition—has permitted an increase in the prevalence of inherited disorders that might historically have been purged from the population. This process is further complicated by the recent, explosive growth of the human population, which has led to a massive accumulation of rare genetic variants; these variants, often appearing in a heterozygous state, represent a "masked load" of potentially harmful mutations that are no longer efficiently filtered by purifying selection. Consequently, while overall mortality has decreased, some researchers argue that modern societies may be experiencing a decline in biological reproductive fitness, as the collective burden of slightly deleterious alleles impacts physiological health and fecundity. As these rare variants drift through the population, the gap between our current genetic health and an idealized, mutation-free genotype continues to widen, posing long-term questions for human microevolution.
In the realm of conservation genetics, a similar but more acute burden is observed in small, fragmented populations through the lens of inbreeding depression and mutational meltdown. Inbreeding depression occurs when a drastic reduction in population size limits mate choice, forcing reproduction between close relatives and leading to an increase in genome-wide homozygosity. This process "unmasks" recessive deleterious alleles that were previously hidden in a heterozygous state, resulting in tangible declines in fitness traits such as juvenile survival, fertility, and disease resistance. If population numbers fall below a critical threshold, this genetic erosion can trigger a "mutational meltdown," a synergistic feedback loop where the accumulation of harmful mutations reduces population growth, causing further shrinkage. As the population becomes smaller, genetic drift overrides the power of natural selection, allowing even highly deleterious mutations to fix randomly. This downward spiral, often referred to as an "extinction vortex," significantly increases the risk of local or global extinction unless countered by management strategies like genetic rescue.
Computational models also provide support for genetic entropy. Sanford’s Mendel’s Accountant simulations show fitness decline under certain parameter choices. The tendency with this program is for the genome to eventually decay under the conditions associated with genetic entropy. Sure, if you set the parameters to those required by universal common descent evolution, then yes, you can get it to produce results consistent with it. However, it is highly unlikely that such parameters are realistic. Furthermore, a simple program where you're making random changes to the computer's memory inevitably results in the computer crashing. As a result, if the genome is indeed similar to a computer program that was originally programmed by a designer, you would expect the same results from random mutations.
6. Major Scientific Criticisms
There are five major scientific criticisms of genetic entropy; four of the five are largely based on the presupposition of universal common descent and its necessities. In other words, this criticism does not come from a position of neutrality, but it results from not being able to see an alternative perspective without looking through the lens of universal common descent. I have frequently encountered this type of criticism, which I have described as, “your theory does not work under my theory, therefore your theory must be wrong.” Although you will not find it on official lists of logical fallacies, it definitely qualifies as one because you cannot disprove a competing theory by assuming the other theory is true and interpreting the evidence under that assumption.
Under the Neutral Theory, the majority of mutations are neutral, not harmful. Neutral mutations do not degrade fitness. First of all, this criticism assumes that neutral theory is correct. This makes it an example of your theory does not work under my theory, so your theory must be wrong. Furthermore, this idea not only harkens back to the falsified idea of junk DNA, but it is also largely based on defining fitness only relative to the environment and selection. It ignores the fact that mutations that provide a benefit within a specific environment can also still be generally harmful, particularly as they accumulate.
The cumulative nature of selection makes the case that even very small selective advantages can dominate over long timescales and that selection acts statistically across populations, not just individuals. However, this criticism ignores the fact that small and slightly harmful mutations will frequently be missed by selection and therefore accumulate over time. It also ignores the fact that selection within a given environment can still be generally slightly harmful. The perspective in this criticism results from only considering mutations harmful, neutral, and beneficial relative to selection, while ignoring other ways in which selected mutations can still be generally slightly harmful.
Another criticism is that recombination and sexual reproduction allow harmful mutations to be separated and removed to speed adaptive change. This really illustrates what the problem is with these criticisms. Now, creationists do not have a problem with adaptive change; furthermore Genetic entropy does not say that adaptive change does not occur. This further illustrates the differences in what is meant by the terminology being used. This criticism makes it quite clear that they are talking about harmful mutations relative to the environment and selection. Genetic entropy, on the other hand, deals with mutations being generally harmful and not just relatively harmful. This criticism ignores the fact that a mutation can be beneficial within a specific environment while still causing general harm to the organism. Such a mutation can provide a environment specific advantage, while damaging the original protein that functions better, resulting in an organism that is generally less healthy, but selected for in that particular environment because it provides an environment-specific advantage
The empirical counterexamples that are cited include “long-lived” species and observed adaptive evolution. So-called long-lived species (bacteria, sharks, horseshoe crabs) persisting for millions of years presupposes an old Earth, whereas genetic entropy is a young Earth model. In other words, it is starting out with a presupposition that the chronological model in which genetic entropy exists is wrong. This makes such criticism circular, a form of circular reasoning. The observed adaptive evolution in laboratory and wild populations is actually irrelevant because genetic entropy does not exclude adaptive change, but can actually help it over a short period of time.
The claim of model parameter bias argues that genetic entropy simulations assume excessively high deleterious mutation rates, unrealistically weak selection, and underestimated beneficial mutation effects. Of course, the flip side could also be true, that evolutionists assume excessively low deleterious mutation rates, unrealistically strong selection, and overestimated beneficial mutation effects. There are two very strong arguments against this claim and in favor of evolutionists being the ones with the bias. The first is the fact that evolutionists tend to refer to fitness in terms of the environment and natural selection, rather than the absolute fitness being referred to by genetic entropy. This is a very important factor to keep in mind, because the evolutionary perspective inflates the number of beneficial mutations while downplaying the number of harmful ones. The second is that for universal common descent to work, evolutionists desperately need low deleterious mutation rates, extremely strong selection, and lots of beneficial mutation effects over time. On the other hand, young-earth creationists could survive with low deleterious mutation rates, extremely strong selection, and lots of beneficial mutation effects over time. As a result, evolutionists are far more likely to be suffering from bias in this area.
Conclusion
The ultimate point of Genetic Entropy is that genomes are degrading over time. This is a result of random changes being made to a system that would have originally been created perfectly. Given the fact that even by the emission of evolutionists, natural selection has no goals, this makes it insufficient to prevent decay, let alone actually build up new complex specific genetic information as required by universal common descent. This renders the long-term evolution needed for universal common descent biologically impossible.
The arguments presented against Genetic Entropy are based largely on the need of evolutionists to keep genomes going for hundreds of millions, if not billions, of years to give the type of change necessary for universal common descent the time it needs to even have the smallest possible chance of working.
Furthermore, most of the arguments in favor of mutations being largely neutral, not only have the origins and the falsified notion of junk DNA, but also in looking at mutations as beneficial, neutral, or harmful in nature solely from a perspective relative to the environment and selection. In other words, most of the arguments in this area ignored the fact that genetic entropy is talking about mutations being harmful in an absolute sense, not just a relative one. When you look at mutations in terms of absolute fitness, Genetic Entropy makes plenty of sense, because even a generally harmful mutation can have benefits under some environmental conditions, with many other slightly harmful mutations being neutral to selection and environment, they simply do not get removed. In thermodynamics, it is ultimately the random motion of heat that causes entropy to increase. In genetic entropy theory, you have the same effect working within the genomes of organisms.
