It is possible for you to hear in the scientific community: To determine the evolutionary history of species by looking at genetic maps and to determine their kinship relations with each other… Our genes are 98% similar with chimpanzees, but this rate drops to 60% with a rice plant, and between 2-3% with a bacterium. up to regression.
These are not fake numbers, they are facts that have been worked on by countless different research groups and that have been revealed as a result of weeks-long analysis of millions of nucleotides through computer programs. Moreover, the power of evolutionary biology is hidden in these analyses: when the evolution trees that we have developed using other methods (morphological analyzes, fossil records, physiological studies, etc.) are checked with genetic analyzes, regardless of genes, we see that evolutionary biology yields accurate results with nearly 100% success. In other words, evolution is a fact and this fact is clearly seen in our genes.
When we talk about genetic similarity between species, we are talking about a real “similarity”. When we look at the proteins encoded by our genes and give us all the features that make us “us”, and the amino acids that are their building blocks, we see that only 5 nucleotides (adenine, thymine, guanine, cytosine and uracil) determine all our genetic features. In fact, much more than that is theoretically possible.
Moreover, studies show that the fact that the genetic maps of living things are completely different from each other will provide them with an absolute advantage. For example, if the genetic codes of chimpanzees and us were not so similar, their SIV (monkey immunodeficiency virus) would not have been able to evolve into HIV (human immunodeficiency virus), which caused AIDS by infecting us. But since there must be alternative genetic blueprints in a logical design of life, the genetic codes of each species (each without exception) are based on the same foundation and are so similar?
There is only one scientific answer to the question: All these species have inherited their genetic codes from a common ancestor, and since evolutionary processes are not flawless and conscious, just like nature itself, it has not been possible for each living thing to develop genetic structures unique to it that are not found in any other. That is, we are the descendants of our ancestors and therefore we carry their genes.
The clearest examples of genetic similarity we see with our close cousins are the presence of common genetic errors in close relatives, in a way that is perfectly in line with the evolutionary trees we constructed before we discovered these examples. In other words, the evolutionary kinships we predict are 100% accurate, no matter where we approach the species. For example, an error in the human chromosome 17, which you can examine in the image, appears in the same place in our close cousins; however, the disappearance of this disease as we go to our distant cousins is one of the best proofs of evolution.
We can compare the evolutionary relationship of shared genetic errors to this: let’s say you’re trying to catch cheaters on an exam (and there’s no way to use technology in either the exam or in cheating detection). If people A and B sitting next to each other give similarly accurate answers to the same questions, this does not give us much information. Because both of them may have worked and given correct answers to the questions. But if A is sitting next to B and his mistakes on the exam questions are 100% the same, that makes us suspicious. Thus, the common errors in these genes, rather than the similarities of the correct parts in the genes, can be used to confirm the evolutionary process, and all attempts so far have resulted in the undisputed triumph of evolutionary biology. Let’s take a look at the example:
On our 17th chromosome, there is the genetic code for a protein called peripheral myelin protein and called PMP-22. On both sides of this gene are identical genetic codes, called CMT1A repeats. Such a situation occurs when the part that carries the genetic code of a protein called COX10 copies itself and sticks to the other end of the PMP-22 by mistake.
We call this an error, because when these two codes come together during meiosis, they cause replication errors (unequal crossing-over). Some of the daughter cells formed as a result of this type of meiosis have two copies of PMP-22, while others do not have this gene at all. If one of these defective copies participates in the formation of the zygote during fertilization, neurological diseases occur.
For example, if paired PMP-22 is fused with a normal germ cell, an offspring with three pairs of PMP-22 will be produced and this offspring will develop Type 1A Charcot-Marie-Tooth disease. In this disease, especially the foot and hand muscles of the individual gradually melt and begin to become distorted. In the end, unbearable aches and pains can be seen. Similarly, if a normal meiosis product were to fertilize a meiotic product that did not carry a copy of PMP-22, a single-copy offspring would be produced, which would eventually result in hereditary neuropathy leading to paralysis.
Starting from the idea of chimpanzee-human close kinship, a fact that evolutionary biology offers us from many different branches, Marcel Keller and his colleagues studied these genes in chimpanzees, their closest relatives, bonobos, gorillas, orangutans, and some other primates. Exactly as predicted, CMT1A repeats were discovered in our closest cousins and bonobos (who are also in the same proximity to us as chimpanzees). It was found that these repetitions cause unequal crossing-over just like ours. But when going to gorillas, orangutans and more distant primates, these repeats were not found. This has entered the scientific record as one of the hundreds of millions of different proofs of evolutionary biology that have been identified so far.
Nexk Page: Why Do All Living Things Use the Same Genetic Code?
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