"The two main features of a person are a large brain size and slow development nervous system inside the mother's womb. Now we have managed to uncover the molecular mechanisms of development of both features of Homo sapiens, which, as it turned out, are turned on at the earliest stages of brain development,” said David Haussler from the University of California at Santa Cruz (USA).

The human and chimpanzee genomes share 99 percent, but our nervous systems develop very differently and suffer from different problems in old age. These differences prevent scientists from using primates to study human disease and how humans acquired the ability to speak and think articulately.

Behind last years researchers have discovered several hundred genes responsible for brain development that differ in structure between human and chimpanzee genomes. However, they were never able to find those sections of DNA that are responsible for the unusually large size of our brain compared to the rest of the body. Many neuroscientists and geneticists suspect that the reason for the striking difference between the two species lies not so much in the structure of genes, but in differences in their activity in different parts of the brain.

Haussler and his colleagues were able to find this, as they say, "Holy Grail of human brain evolution" by studying the structure of various genes on the first human chromosome, the deletion of which very often leads to the development of microcephaly, and duplication or damage - to macrocephaly or severe forms of autism.

In this section of the genetic code, as scientists explain, there is a set of genes from the NOTCH2 family, which are responsible for the development of "blanks" of neurons and the formation of future brain tissues in the embryo of mammals. Their structure is almost the same in the DNA of all primates, and, as scientists from Russia have recently shown, they work in the same way during the development of the embryo.

By observing the activity of these DNA regions in stem cell cultures, Haussler and his colleagues noticed one simple thing that for some reason all other scientific teams missed. It turned out that an "extra" gene works in human cells, which is absent or does not work in the blanks of neurons in chimpanzees, gorillas and other primates.

After studying its structure, experts came to the conclusion that the NOTCH2NL gene appeared in the DNA of our ancestors about three to four million years ago as a result of a series of "successful" mistakes when copying the first chromosome. The first error resulted in one of the NOTCH2 family genes being partially copied and inserted into the DNA of the first Homo. This turned it into a "junk" pseudogene that played no role in the body's work.

The second mistake “repaired” its damaged parts, as a result of which a new DNA segment appeared in the protohuman genome, which radically changed the program for the development of the nervous system, which was then copied several more times during subsequent evolution. As the experiments of scientists on stem cells have shown, the removal of NOTCH2NL leads to the fact that the blanks of nerve cells begin to "grow up" faster and divide less often.

"One stem cell involved in the growth of the brain can give life to two neurons or another blank and one nerve cell. NOTCH2NL makes them choose the second option, which allowed our brains to grow in size. As often happens in the history of evolution, a small change in how stem cells work led to very big consequences," the experts conclude.

It is extremely rare for two of the most respected scientific journals in the world - the British Nature and the American Science - to simultaneously devote a significant part of their regular issues to the same topic - this happens extremely rarely. And if it happens, it testifies to the extreme importance of this topic. So the publication of 12 articles at once on the decoding of the chimpanzee genome and its comparison with the human genome is, of course, an extraordinary event.

An international consortium was formed to implement a project on mapping and comparative analysis of the chimpanzee genome. It included 67 scientists out of 23 scientific institutions 5 countries - USA, Israel, Spain, Italy and Germany. Coordinated the work of genetics Harvard University and Massachusetts Institute of Technology in Boston. And blood for DNA analysis was given by a young male chimpanzee named Clint, an inhabitant of one of the enclosures of the Yerkes National Primate Research Center in Atlanta, Georgia. Unfortunately, in January of this year, the donor died of acute heart failure in the prime of his life, at the age of 24. His skeleton is now on display at the Field Museum in Chicago. However, the most important value that humanity inherited from Clint is a portion of his blood, which served as the source material for deciphering and analyzing the chimpanzee genome. Now primates have added to the list of organisms whose hereditary material is fully mapped. This list now includes hundreds of positions: there are fungi, and bacteria, including pathogens of dangerous infectious diseases (anthrax, tularemia, plague, typhoid), and plants (rice, coffee tree), and insects (malarial mosquito), and birds (eg chicken) and mammals (mouse, rat, dog, pig, cow). However, anthropoid apes occupy in this list, of course, a very special place. According to Robert Waterston, head of genomic research at the University of Washington School of Medicine in Seattle, "the study of chimpanzees as the closest living relative of humans on Earth can give us the most information about ourselves." However, before moving on to a discussion of the results obtained by scientists, I will allow myself a small digression - or, if you like, a reminder - to make it clearer what, in fact, we are talking about.

As you know, any living organism consists of cells, and in the nucleus of each cell there is one and the same set of genetic information characteristic of a given biological species. This set is called the genome. Chromosomes are the carrier of genetic information. The chromosome is a molecule of deoxyribonucleic acid (abbreviated as DNA) and consists of two long polynucleotide chains twisted one around the other and connected to each other by the so-called hydrogen bonds. This molecule is called a double helix, it can be somewhat simplified to imagine in the form of a twisted rope ladder. Different animal species have different numbers of chromosomes. So, the human genome consists of 23 pairs of chromosomes - in each pair, one chromosome comes from the father, the other from the mother. In the fruit fly - Drosophila - the cell nuclei contain 4 pairs of chromosomes, and, for example, bacteria have only one unpaired chromosome. Genes are located on chromosomes in strictly defined areas - a kind of unit of heredity. Chemically, genes consist of molecules of 4 nitrogenous compounds - adenine, cytosine, guanine and thymine. These so-called nucleotide bases are repeated in a strictly defined order, forming adenine-thymine and guanine-cytosine pairs. One gene can contain from several thousand to more than two million nucleotide bases. It is their sequence that determines the specific functions of each particular gene.

Figuratively, the genome can be imagined as follows: the cell nucleus is a library that stores instructions for ensuring life; chromosomes play the role of bookshelves; there are books on the shelves - DNA molecules; genes are chapters within books, and nucleotide bases - adenine, thymine, guanine and cytosine, which are usually denoted by the initial letters of their names A, T, G and C - this is the same alphabet in which the text of the genome is written. The human genome, for example, is a chain of 3 billion 200 million letters.

But the fact that genes exist and that they work is not enough: they must work in different ways, providing certain specific functions. After all, the cells of different organs and tissues - say, skin, liver, heart and brain - are strikingly different from each other. Meanwhile, the core of each of them contains the same set of genes. It's all about the activity of genes: some genes work in some cells, others work in others. So chromosomes are carriers not only of genes, but also of those protein factors that control their functions. This set of genes, together with regulatory elements, makes up the structure within the cell that provides all the necessary functions.

And now, armed with this knowledge, let's return to the results that were obtained during the decoding of the chimpanzee genome. For obvious reasons, the catalog of those differences in the genetic codes of chimpanzees and humans that have accumulated over the past 6-plus million years, since the evolutionary paths of two species that had a common ancestor, is of the greatest interest to both specialists and the general public. dispersed. Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology in Leipzig and one of the project participants evaluates the resulting database as follows:

It is an extremely useful tool that will help us in finding an answer to the question of what genetic mutations explain the striking difference between humans as species from all other animal species. One of the directions of this search is to try to identify the relationship between genetic differences and the activity of certain genes.

First of all, it should be noted that the obtained data surprised the experts. The main surprise is that the chimpanzee genome, as it turned out, matches the human genome by 98.8 percent. Roughly speaking, the genetic similarity between a human and a chimpanzee is 10 times greater than between a mouse and a rat. Amateurs, most likely, will be struck by such a great similarity, this almost complete identity of the genomes, but scientists were surprised by just the opposite: that the difference turned out to be quite significant. Moreover, this figure - a 98.8 percent coincidence - does not fully reflect the state of affairs. It is obtained by comparing the individual letters of the genetic code in the coding DNA. Here, scientists counted 35 million discrepancies, which accounted for 1.2 percent of the entire chimpanzee genome, which has about 3 billion 100 million nucleotide pairs. But that's not all: significant differences were also found in the distribution of those sequences of nucleotide bases that form non-coding, "selfish" DNA. These mismatches accounted for another 2.7 percent of the entire genome, which added up to almost 4 percent.

In total, chimpanzees lacked 53 of the genes that humans have. In particular, the chimpanzee genome lacks three genes that play a key role in the development of inflammation, which is known to be the cause of many human diseases. On the other hand, humans seem to have lost in the course of evolution a gene that protects animals from Alzheimer's disease.

The most significant differences concern the genes that regulate the immune system. According to Professor Evan Eichler, of the University of Washington School of Medicine in Seattle, this indicates that in the course of evolutionary development, chimpanzees and humans had to confront different pathogens and fight different diseases. Svante Pääbo explains:

First of all, we asked ourselves which DNA segments can clarify the history of the origin of a number of diseases. We know that some of the genetic structures that cause this or that disease are found in both chimpanzees and humans. Apparently, these structures were inherited by both species from their common ancestor. However, there are diseases, the genetic predisposition to which arose in the process of evolution only in humans. In these cases comparative analysis DNA will give us valuable information about the genetic nature of such diseases and about the susceptibility of humans as a species to them.

Analyzing the collected data, the scientists produced a kind of computer overlay of a chimpanzee genome map on a map of the human genome, which allowed them to distinguish three categories of so-called DNA duplications - those that are in the human genome, but are absent in the chimpanzee genome, those that are present in the genome chimpanzee, but are absent in the human genome, and those that are present in the genome of both species. A DNA duplication is a form of mutation in which a portion of a chromosome is duplicated. In this case, DNA segments with a length of at least 20 thousand nucleotide pairs were taken into account. It turned out that about a third of the DNA duplications found in humans are absent in chimpanzees. According to Eikler, this figure pretty much surprised geneticists, since it indicates a very high frequency of mutations in a short period of time - by evolutionary standards. At the same time, analysis of DNA duplications, which are unique to the chimpanzee genome, showed that although the number of places where they occur is relatively small, the number of copies of duplicated segments is much higher than in humans. And in cases where DNA duplication occurs in both chimpanzees and humans, it is usually represented by a large number of copies in chimpanzees. In particular, scientists have found a segment that occurs 4 times in the human genome, and 400 times in the chimpanzee genome. Interestingly, this site is located near the region that in chimpanzees and other great apes is divided into 2 chromosomes, and in humans is merged into one - chromosome number 2.

However, the striking differences between monkeys and humans are explained not so much by the inconsistencies in the genetic code, but by the different activity of the genes, emphasizes Svante Päbo. A group of researchers led by him studied and compared the activity of 21 thousand genes in the cells of the heart, liver, kidneys, testicles and brain of both primates. It turned out that there is no complete coincidence of gene activity in any of these organs, but the differences are distributed extremely unevenly. Surprisingly, scientists registered the smallest differences in brain cells - they amounted to only a few percent. And the greatest differences were found in the testicles: here every third gene has a different activity. However, this is quite understandable if we keep in mind that chimpanzees do not form monogamous families, but live in groups, a kind of communes, numbering 25-30 individuals of both sexes. That is, "promiscuity" in chimpanzees is much more widespread than in humans. To increase their chances of promiscuity procreation, male chimpanzees must produce massive amounts of sperm. It is no coincidence that their testicles are ten times larger than those of Homo sapiens men. But, of course, it's not just about size, says Svante Päbo:

Our data indicate a very high activity of those genes on the Y chromosome that are directly responsible for sperm production.

And the fact that a person is physically much weaker than a chimpanzee, scientists have found a genetic explanation: in monkeys, the muscles work 5-7 times more efficiently because in all representatives of the human genus, the MYH16 gene encoding “myosin” - a muscle fiber protein - is represented by a mutated copy.

However, if we focus on the question, what is the main genetic difference between a human as a biological species and apes and what explains such a successful expansion of humans in the course of evolution, then the answer, apparently, should be sought in the 6 regions of the genome identified by scientists. In the human genome, these regions, containing a total of several hundred genes, are so stable that they are practically identical in all people; in the chimpanzee genome, on the contrary, they often contain mutations. Apparently, scientists believe, these areas played an extremely important role in the process of our evolution. It is noteworthy that one of these regions contains the FOXP2 gene, one of the 4 genes responsible for the development of speech. As experiments have shown, under laboratory conditions, monkeys are able to learn a fairly significant set of signs and symbols; chimpanzees living in the wild use a very rich assortment of sounds to communicate; however, they are physically unable to make those movements with their lips and tongue that are necessary for articulated speech. Perhaps it was the mutation of the FOXP2 gene that became one of the key factors that determined such a different evolutionary fate. different types primates.

1. Humans have 23 pairs of chromosomes, while chimpanzees have 24. Evolutionary scientists believe that one of the human chromosomes was formed by the fusion of two small chimpanzee chromosomes, rather than an inherent difference resulting from a separate act of creation.

2. At the end of each chromosome is a strand of a repetitive DNA sequence called a telomere. Chimpanzees and other primates have about 23 kb. (1 kb is equal to 1000 nucleic acid heterocyclic base pairs) of repeating elements. Humans are unique among all primates, their telomeres are much shorter: only 10 kb long. (kilobases).

3. While 18 pairs of chromosomes are "virtually identical", chromosomes 4, 9 and 12 indicate that they have been "remade". In other words, the genes and marker genes on these human and chimpanzee chromosomes are not in the same order. It makes more sense to think that this is an inherent difference due to the fact that they were created separately and not "remade" as evolutionists claim.

4. The Y chromosome (sex chromosome) is especially different in size and has many marker genes that do not match (when lined up) between humans and chimpanzees.

5. Scientists have prepared a comparative genetic map of the chimpanzee and human chromosomes, in particular the 21st chromosome. They observed "large, non-random patches of difference between the two genomes." They found a number of sites that "could correspond to insertions that are specific to the human lineage."

6. The size of the chimpanzee genome is 10% larger than the size of the human genome.

These types of differences are usually not taken into account when calculating the percentage similarity of DNA.

In one of the most extensive studies comparing human and chimpanzee DNA, researchers compared more than 19.8 million bases. Although this number seems large, it represents less than 1% of the genome. They counted middle identity in 98.77% or 1.23% difference. However, in this study, as in others, only substitutions were taken into account and no insertions or deletions were taken into account, as was done in Britten's new study. A nucleotide substitution is a mutation where one base (A, G, C, or T) is replaced by another. Insertions or deletions are found where nucleotides are missing when two sequences are compared.

Replacement Insertion/deletion

Comparison between base substitution and insertion/deletion. Two DNA sequences can be compared. If there is a difference in nucleotides (A instead of G), then it is a substitution. Conversely, if there is no basis, then it is considered to be an insertion/deletion. It is assumed that the nucleotide was inserted into one of the sequences, or it was removed from another sequence. It is often difficult to determine whether a difference is the result of an insertion or a deletion. In fact, inserts can be of any length.

Britten's study looked at 779 kilobases nucleic acids in order to scrutinize the differences between chimpanzees and humans. Britten found that 1.4% of the bases were changed, which was consistent with previous studies (98.6% similarity). However, he found a much larger number of inserts. Most of them were only 1 to 4 nucleotides long, while there were a few nucleotides that were over 1000 base pairs long. Thus, insertions and deletions added 3.4% additional different base pairs.

Whereas previous studies have focused on base substitution, they miss the biggest contribution to the genetic differences between humans and chimpanzees. The missing human or chimpanzee nucleotides were found to be twice as many as the number of nucleotides replaced. Although the number of substitutions is about ten times greater than the number of insertions, the number of nucleotides involved in insertions and deletions is much greater. These inserts were noted to be present in equal numbers in human and chimpanzee sequences. Therefore, insertions or deletions did not occur only in chimpanzees or only in humans, and they can be interpreted as an inherent difference.

Will evolution be questioned now that the similarity in chimpanzee and human DNA has dropped from >98.5% to ~95%? Probably not. Regardless of whether the degree of similarity drops even below 90%, evolutionists will still believe that humans and apes descended from a common ancestor. Moreover, the use of percentages obscures a very important fact. If 5% of DNA differs, then this corresponds to 150,000,000 base pairs of DNA that are different from each other!

A number of studies have shown significant similarities between nuclear DNA and mitochondrial DNA in modern humans. In fact, the DNA sequences of all humans are so similar that scientists generally conclude that there is "a recent single origin of all modern humans, with a general replacement of older populations." To be fair, evolutionists' calculations of the date of origin of the "most recent common ancestor" (CHOP), i.e., "recent common ancestry," came up with a number of 100,000-200,000 years ago, which by creationist standards is not recent. These calculations were based on comparisons with chimpanzees and the assumption that the common ancestor of chimpanzees and humans appeared approximately 5 million years ago. But studies that used generational comparisons and genealogical comparisons of metachondrial DNA pointed to the origin of even more recent SNOP - 6,500 years!

A single-generation study of observed mutations points to a more recent common human ancestor than phylogenetic calculations suggesting a relationship between humans and chimpanzees. It is hypothesized that mutational regions are the cause of the differences between these classes. However, in both cases they rely on uniformitarian principles, namely that percentages calculated in the present can be used to extrapolate the time of events into the distant past.

The above examples demonstrate that the conclusions scientific research may be different depending on how these studies are conducted. Humans and chimpanzees can have 95% or >98.5% DNA similarity depending on which nucleotides are considered and which are excluded. Modern man may have a single recent ancestor that appeared

Links and notes

(For those who find Darwinism difficult)

Nothing at all

Only three genes have been found in humans that distinguish them from chimpanzees

If only you knew from what rubbish ...
Anna Akhmatova

People love looking at pictures of animals. Cats, dogs, horses, llamas - all of them, especially cubs, seem very cute to us. However, few people call monkeys cute or cute, especially higher primates. These animals look like a parody of a person. Clear similarities mixed with distinctly animal features evoke mixed feelings.

Man and monkey are really similar. At the DNA level, the similarity between Homo sapiens And Pan troglodytes- chimpanzee - exceeds 98 percent. In numbers, this difference seems not so small: of the three billion "letters" of the human genome, as many as 60 million are unique to H. sapiens. In this case, the numbers create a false impression of the abyss separating man from ape. Almost all the genes of these two groups of organisms differ only in minor variations in the DNA sequence.

Scientists still cannot explain how these small genetic differences were able to provide a colossal evolutionary leap from apes to humans. The first answer that comes to mind is the sequences characteristic of H. sapiens, made up in his genome into special "genes of humanity". However, in practice, this theory is not confirmed: researchers have not found unique genes in humans. All genes H. sapiens evolved from the genes of a common ancestor with chimpanzees. The authors of the new study for the first time found as many as three exceptions to this rule.

Evolution at the gene level

Before describing the new discovery, it is worth a little more detail about how exactly the evolution of genetic sequences occurs. The genomes of the very first living organisms that appeared on our planet contained only a few hundred genes. To reproduce, the first inhabitants of the Earth divided their body, consisting of a single cell, in two. Each of the offspring received one copy of the parental genome. Copying the DNA of "father" (or "mother") occurred with errors - some genes were lost, while others, on the contrary, appeared in a doubled version. In some cases, "extra" genes did not lead to the death of the host. They persisted in the chain of generations and gradually mutated. After several tens of hundreds of copies, the sequence of such genes changed beyond recognition. Accordingly, the sequence of proteins encoded by the genes also changed. Gradually, the structure of living beings became more complicated, but the mechanisms for the formation of new genes remained unchanged.

In some cases, new genes appeared without doubling old ones - mutations also appeared in genes present in a single copy. If the changes did not worsen the viability of the organism, they could be preserved in a series of generations. Eventually, a critical number of such neutral or positive mutations accumulated in the gene, and new functions appeared in the encoded protein.

Another way to form new genes is to lose part of the sequence. A shortened gene sometimes continued to work no worse than a full-fledged copy, in addition, the place of the lost "letters" could be occupied by neighboring DNA sequences. Another option for the birth of new genes is the "merging" of old ones with each other or their splitting.

In all the cases described, genes are not created de novo: the basis for them is always the variants that already exist in the body. Biologists were confident in this fact until 2006, when the journal Proceedings of the National Academy of Sciences there was a group of researchers working with the fruit fly Drosophila melanogaster.

The authors found as many as five genes in the Drosophila genome that its closest relatives do not have. All of them were formed from the so-called "junk" DNA (junk DNA). With this hard-hitting epithet, scientists designate DNA sequences that do not code for proteins, the function of which is unknown. The term was proposed in 1972 by Japanese-American geneticist Susumu Ohno and has since caught on. In developed organisms, "junk" DNA makes up more than 95 percent of the genome.

After the release of the "fly" work, biologists rushed to look for unique genes in other organisms. However, to date, they have only been found in yeast. However, the authors of a new study led by Aoife McLysaght of Trinity College Dublin set out to find new genes in humans.

Keys to Humanity

McLiseth and colleagues compared genomes H. sapiens And P. troglodytes. Using special programs, they compared the sequences of currently known human and chimpanzee genes. The authors found 644 genes in the human genome that have no analogues in chimpanzees.

The order of the genes in chimpanzees and humans is practically the same. The researchers closely studied the regions of the monkey genome where suspicious sequences could be located. In existing DNA databases P. troglodytes large chunks of code were missing in some of these places, so the researchers had to exclude 425 of the 644 genes found from consideration.

In the next stage of the work, the scientists re-searched the remaining 219 sequences in the chimpanzee genome using a slightly different algorithm. 150 supposedly unique human genes in the genome P. troglodytes similarities have been found. Thus, the "circle of suspects" narrowed down to 69 genes. Scientists crossed out from this list sequences that were found in the genomes of species other than chimpanzees. Finally, McLiseth and her co-authors abandoned genes that were only present in one database of human DNA and could have been entered there by mistake.

All stages of selection passed only three genes - CLLU1, C22orf45 And DNAH10OS. To once again be convinced of their uniqueness for humans, the researchers checked the genomes of the macaque, gibbon and gorilla. Sequences that look like CLLU1, C22orf45 And DNAH10OS, were found in all the studied primates, however, they could not be full-fledged genes and were present in the "junk" DNA.

In order to be considered a gene, the sequence must contain certain combinations of "letters", in particular, marking the end and beginning of the gene. Such characteristic "letter combinations" are recognized by the enzymes responsible for protein synthesis from this gene. The macaque, chimpanzee, gibbon, and gorilla had no distinguishing features characteristic of genes. Moreover, they had areas that interfered with the full-fledged work of enzymes. Moreover, in all primates (except humans), these areas were the same.

The researchers suggested that in the course of human evolution in some regions of the "junk" DNA present in primates, the necessary changes have accumulated that allowed them to become real genes. It was the work of these genes that led to the appearance of the genus Homo.

The idea that human and chimpanzee DNA are almost 100% similar is generally accepted. Quoted figures range from 97%, 98%, or even 99%, depending on who is talking about it. What are these statements based on and does this data mean that there is not so much difference between humans and chimpanzees? a big difference? Are we just evolved primates? The following principles will help in a correct understanding of this issue:

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 car and a Volkswagen Beetle. Both cars are equipped with a flat, horizontally mounted, air-cooled, 4-cylinder engine, which is located at the rear of the car. The two cars have independent suspensions, two doors, a luggage compartment (trunk) located in the front, and many other similar features ('homologies'). Why do these two very different cars have so much in common? Because they were designed by the same designer! Whether the similarity is morphological ( appearance) or biochemical, it is by no means evidence for evolution.

If people were completely different from all other living beings, or in general every living being was completely different from each other, would this point to the Creator? No! According to human logic, we would rather assume that there are probably many creators, and not one. The unity of creation is evidence of the existence of the One True God, by whom all things were created (Romans 1:18-23).

If humans were completely different from all other living forms, how would we then be able to 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 the amino acids, sugars and other components of other life forms, if they were different from the amino acids, sugars and other components of our body? That is, biochemical similarity is necessary so that we can eat!

We know that the DNA that is 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 the DNA of a cow and a bacterium. If this were not the case, then the role of DNA as an information carrier in living organisms would be called into question. Similarly, humans and primates share many morphological similarities, so it is natural that their DNA is similar. Of all animals, chimpanzees are the most similar to humans, and therefore chimpanzee DNA has 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 the cells human body act in many ways 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 functions in both cell types. Some of these sequences, which, for example, code for MHC (major histocompatibility complex) proteins, are almost 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 a sequence of four chemical components known as nucleotides, abbreviation C,G,A,T. Groups of three nucleotides (triplets) are simultaneously ‘read’ in the cell using a complex translational mechanism in order to establish the sequence 20 different types amino acids to combine them into proteins. Human DNA has at least 3,000,000,000 nucleotides in sequence. Chimpanzee DNA hasn't been anywhere close to being able to make an appropriate comparison (this would take a long time - imagine if you had to compare two stacks of 1,000 large books to find similarities and differences, sentence by sentence!).

Where, then, did this “97% similarity” come from? 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 combined 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 ‘downward’ curve). Why then is the 97% figure so common? Most likely, because it served a specific purpose - instilling evolutionary ideas in scientifically uneducated people.

It is interesting that the initial documents did not contain the original data, and the reader was forced to accept the interpretation of these data "on faith". Sarich and co-authors received input data and used them in a detailed discussion of which parameters should be applied in the study of homology. Sarich found Sibley and Alquist to be very sloppy in deriving their data, as well as in their statistical analysis. In examining this data, I found that even if everything else was left aside, the 97% figure came about as a result of making the most important statistical error - rounding two numbers without taking into account the difference in the number of observations that contributed to each figure. When calculated correctly, this number is 96.2%, not 97%. Since there are no exact repetitions in the data, the figures published by Sibley and Ahlquist are not credible.

What if the DNA molecule of humans and chimpanzees 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 was calculated that the amount of information contained in 3 billion base pairs of nucleic acids in the DNA of each cell of the human body is equal to the amount of information contained in 1000 books, each the size of an encyclopedia. If people differ by “only” 4%, this still amounts to 120 million nucleotides, equal to approximately 12 million words, or 40 big books information. Undoubtedly, 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 necessarily. Compare the following sentences:

There are many scientists today who question the evolutionary belief system and its atheistic philosophical implications.

There are few scientists today who question the evolutionary belief system and its atheistic philosophical implications.

These sentences are 97% similar, but at the same time they have a completely opposite meaning! The strong similarity here is that large DNA sequences can be turned on or off by relatively small control sequences. Data on DNA similarity means at all Not what the propagandists of the theory of evolution claim!

Links and notes

1. Evolutionary anthropologist Jeffrey Schwartz at the University of Pittsburgh argues that humans are morphologically more similar to orangutans. Acts and Facts, 16(5):5, 1987.
2. Sibley and Alquist, 1987, J. Molec. Evol. (26:99–121).
3. Sarich et al. 1989. Cladistics 5:3–32.
4. Ibid
5. Studies of molecular homology can be of great help to creationists in establishing what the original "kinds" were and what has happened since then, causing the formation of new species within each "kind". For example, the varieties/species of finches that live in the Galapagos Islands probably originated from the original small group that made it to the islands. Gene recombination and natural selection may have been the cause of modern varieties of finches on the islands - just as all dog breeds that exist in the world were artificially bred from the original wild dog. Interestingly, studies of molecular homology are most consistent with Scripture when it comes to biblical genera, and contradict the major predictions of evolution regarding the relationship between major groups such as types and classes.
6. Michael Denton Denton, 1985. Evolution: Theory in Crisis.(Burnett Books, London).
7. Haldane's dilemma points to a problem for evolutionists in getting genetic changes in higher organisms, especially those that have long generation times. Due to the cost of replacing (death of the unusable) one gene with another in a population, it would take more than 7×1011 years of human generations to replace 120 million base pairs. In other words, over 10 million years (twice the time supposedly since the hypothetical common ancestor of chimpanzees and humans lived), there would have been only 1667 replacements, or 0.001% difference. There just wasn't enough time for the ape-like creatures to turn into a human. And this further understates the problem for evolution, since perfect efficiency is assumed in this calculation. natural selection and ignores harmful processes such as inbreeding and genetic drift, as well as the problems posed by pleiotropy (when one gene is responsible for more than one trait) and polygeny (when more than one gene is responsible for one trait). See Remine, The Biotic Message(St. Paul Science, St. Paul, Minnesota, 1993), pp. 215–217.