Beneficial mutations are a hot topic in the biology field. They are a necessity for most if not all models of evolution and, as such, are highly sought after among evolutionary biologists. This fervor is even more heightened by the sheer number of beneficial mutations needed to move a microbe to a man. Thus numerous beneficial mutations have been proposed over the years. However, in order to determine whether beneficial mutations exist, we must first agree on a definition of beneficial mutations.
Numerous beneficial mutations have been postulated to be part of the evolutionary process. There are a few common examples, such as microbial antibiotic resistance, lactose tolerance, and so on. One of the most egregious examples that I’ve seen used is the almond mutation. Normal almonds are very bitter to the taste, serving as a repellant to animals and man alike. However, in the mutated almond, the bitter taste is removed, leading to it being enjoyed by both animals and man. This serves no benefit to the almond tree. In fact, it is a net decrease in fitness since the almonds are eaten instead of surviving. Calling this a beneficial mutation is patently absurd as it harms the almond tree, it does not help it.
Beneficial mutations according to the evolutionist, is anything that improves the fitness of an organism in a given situation, whether that situation is natural or not. This leads to the question of what is fitness? According to the evolutionist, an organism’s fitness is defined by how many of its offspring survive to reproduce. An organism that produces a lot of surviving offspring is thus very fit, while a sterile individual has very low fitness according to evolutionary biology. However, that does not actually work in an evolutionary context for a number of reasons.
The first problem is with the definition of fitness. Defining fitness as reproductive success raises the question of what about traits that have no effect on reproduction? As an example, people with sickle-cell anemia, another commonly cited “beneficial mutation”, incur a fitness cost to their offspring if they marry another person with sickle cell, or a net neutral if they do not. This is due to sickle-cell causing some serious health problems when an individual is homozygous for it. It would appear that some mutations, which appear “beneficial”, are completely neutral from a reproductive standpoint, or even deleterious.
This leads into the next problem with this definition of beneficial mutations. For the evolution story to work, a long line of beneficial mutations are needed. Based on the evolutionary idea of beneficial mutations, each of these mutations must increase the reproductive fitness of the organism. Consider the lactose tolerance mutation in humans. This mutation does nothing to increase the likelihood of producing viable offspring. Thus by the evolutionists’ own definition, lactose tolerance is not a beneficial mutation.
However, the problem runs even deeper than that. For evolution to work, each mutation must increase the fitness of the organism. It further must not decrease fitness as a balance. In other words, a truly beneficial mutation should not incur a fitness cost. The cost to the reproductive success of the organism must be zero. The reason behind this is simple. If it incurs a fitness cost, then it does not increase fitness as the animal moves up the evolutionary tree of life. In other words, each beneficial mutation needs to be purely beneficial. If not, then, over the course of evolution, the fitness costs would build up to a point where the genome would be completely polluted and the organism would go extinct. Thus if the mutation is not purely beneficial, if it incurs a fitness cost, then it does nothing to help evolution. In fact, it speaks against the evolutionary dogma. The fitness cost is fatal.
Does such a purely beneficial mutation exist, that only increases fitness? To my knowledge, no such mutation has been found. Every single mutation incurs that I am aware of is harmful, even if there are some situational benefits to having it. This is true of every known mutation, including the commonly cited beneficial ones. Thus, at this point, it can be safely postulated that no beneficial mutations are known. This is not to say they do not exist, merely that they are not demonstrated.
One of the interesting things in play here is that the evolutionists equivocate on their own definition of fitness. Usually, it is based on reproductive success, but, for beneficial mutations, they want it to mean survival value. Though the two can be similar, there is a broad distinction between the two that does not allow for them to be used interchangeably.
In short, based on the evolutionist’s own definitions of a beneficial mutation and fitness, there are no known beneficial mutations. While many have been postulated, none have yet met the requirement for a truly beneficial mutation. It is possible some examples might exist, but even if they do, there are simply not enough of them to account for hundreds of millions of years of evolution.