The idea that the DNA of humans and chimpanzees is almost 100% similar is generally accepted. The quoted figures vary: 97%, 98%, or even 99%, depending on who is talking about it. What are these claims based on, and does this data mean that there is not much difference between humans and chimpanzees? Are we just evolved primates? The following principles will help in the correct understanding of this issue:
- The similarity ('homology') is not evidence of a common ancestor (as the theory of evolution claims), but rather evidence of a common designer (creation). Compare a Porsche and a Volkswagen Beetle. Both cars are equipped with a flat, horizontally positioned, air-cooled, 4-cylinder engine located at the rear of the car. These two cars have independent suspensions, two doors, a luggage compartment (trunk) located at the front, and many other similar characteristics ('homologies'). Why do these two so different cars have so many characteristics in common? Because they were designed by the same designer! Whether the similarity is morphological (appearance) or biochemical, it has nothing to do with the evidence for evolution.
- If people were completely different from all other living creatures, or in general, every living being was completely different from each other, would this indicate the Creator? Not! According to human logic, we would rather assume that there are probably many creators, not just one. The unity of creation is evidence of the existence of the One True God, by whom everything was created (Romans 1: 18-23).
- If humans were completely different from all other living forms, how could we then live? If we eat food so that our body receives the nutrients and energy necessary for life, what would we eat if every other organism living on earth was completely different from us in its biochemical composition? How would our body be able to digest these substances, and how would we use amino acids, sugars and other components of other forms of life, if they were different from amino acids, sugars and other components of our body? That is, biochemical similarity is necessary in order for us to eat!
- We know that the DNA found in cells contains a lot of information necessary for the development of our body. In other words, if two organisms are similar, then their DNA will also have some similarity. The DNA of a cow and a whale, two mammals, should have more similarities than that of a cow and bacteria. If this were not so, then the role of DNA as an information carrier in living organisms would be questioned. Likewise, humans and primates have many morphological similarities, so it is natural that their DNAs are similar as well. Of all animals, chimpanzees are the most similar to humans, and therefore chimpanzee DNA bears many similarities to human DNA.
- Certain biochemical properties are common to all living things, so there is even a degree of similarity between yeast DNA, for example, and human DNA. Since human cells act much like yeast cells, this means that humans and yeast have similarities in the DNA sequence. These similarities are responsible for the genetic code for enzymes that perform the same function in both types of cells. Some of these sequences, which for example encode MHC (Major Histocompatibility Complex) proteins, are nearly identical.
- How about 97% (or 98% or 99%!) Similarities between humans and chimpanzees? These numbers don't mean exactly what the popular publications (and even some decent scientific journals) claim. DNA contains its information in the sequence of four chemical components known as nucleotides, abbreviated as C, G, A, T. Groups of three nucleotides (triplets) are simultaneously 'read' in the cell using a complex translational mechanism in order to sequence 20 different types of amino acids to combine them into proteins. Human DNA has at least 3,000,000,000 nucleotides in sequential order. The chimpanzee's DNA was not even close enough to be able to make an appropriate comparison (this would take a long time - imagine if you had to compare two stacks of 1000 large books,to find similarities and differences, sentence by sentence!).
Where did this '97% similarity' come from then? The basis for the emergence of these data was a rather crude technique called DNA hybridization, in which small pieces of human DNA were divided into single strands and then connected into double strands (duplexes) with chimpanzee DNA. However, there are many different reasons why DNA crosses or not, and only one of them is the degree of similarity (homology). Therefore, this somewhat random figure is not used by those working in molecular homology (other parameters are used, derived from the shape of the 'falling' curve). Why, then, is the 97% figure so common? Most likely, because it served with a specific purpose - the suggestion of evolutionary ideas to scientifically uneducated people.
Interestingly, the initial documents did not contain the original data, and the reader was forced to take the interpretation of this data 'on faith'. Sarikh et al obtained the raw data and used them in a detailed discussion of which parameters should be used in homology studies. Sarikh found Sibley and Alquist to be very careless in deriving their data, as well as in their statistical analysis. Examining this data, I found that even if everything else was not criticized, the 97% figure came from the most important statistical error - rounding two digits without taking into account the difference in the number of observations that contributed to each digit. If calculated correctly, this number is 96.2%, not 97%. Since there are no exact repetitions in the data, the figures published by Sibley and Alquist are not credible.
What if human and chimpanzee DNA molecules were even 96% homologous? What would that mean? Would this mean that humans could 'evolve' from a common ancestor along with chimpanzees? Not at all! It has been calculated that the amount of information contained in the 3 billion base pairs of nucleic acids in the DNA of every cell in the human body is equal to the amount of information contained in 1,000 books, each about the size of an encyclopedia. If people differ by 'only' 4%, this is still 120 million nucleotides, equal to about 12 million words, or 40 large books of information. There is no doubt that for mutations (random changes) this is an obstacle that cannot be overcome.
Does a high degree of similarity mean that two DNA sequences have the same meaning or function? No, not required. Compare the following sentences:
There are many scientists today who question the evolutionary belief system and its atheistic philosophical implications.
There are not many scientists today who question the evolutionary belief system and its atheistically philosophical implications.
These sentences are 97% similar, but at the same time they carry the completely opposite meaning! The strong similarity here is that large DNA sequences can be turned on or off with relatively small control sequences.
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Editor's Note: The purpose of this article is to prove that one very common 'proof' is false that humans evolved from primates, as the title of the article suggests. It is simply impossible to consider all the other 'proofs' of human evolution in one article. See the article "Anthropology" for questions about the fossils of the alleged 'ape-man'.
Don Batten
