Did you just say that the genetic chain of these animals was set by humans? How is that done? ”

Ye Xiuwen frowned, because he was puzzled by this, because the gene chain was not so easy to rewrite. Otherwise, the development of mankind today will definitely not be limited to the present.

So he had to figure it out, because if someone manipulated the gene chain, then it was probably artificial.

At this time, Yang Mengmeng thought for a while and said: "I don't know, whether you will understand what I said, but I will tell you what is going on in the most concise and easy-to-understand language."

There are three main factors that cause changes in gene frequencies: selection, genetic drift, and migration.

Selection is the selection of the environment for variation, that is, the process of preserving favorable variation and eliminating unfavorable variation. The essence of selection is to change the gene frequencies of the population in a targeted manner.

Selection is the dominant factor in biological evolution and speciation, and whether the mutations that have occurred can be retained to continue to evolve or become the basis of new species must be tested by natural selection, and natural selection determines the survival or elimination of mutation types.

Natural selection retains only the type of variation that is in harmony with the environment (favorable variation), which shows that natural selection is directional.

After countless selections, the genes of favorable variations of a certain species in a certain region will be strengthened, and the genes of unfavorable variations will be gradually eliminated, thereby changing the gene frequencies of species in the same region or in different regions to form new types of species in the same region or subspecies of the same species in different regions, or after long-term selection, the changes in gene frequencies will reach the level of reproductive isolation, and new species will be formed. Choice determines the fate of different types of mutations, which in turn determines the direction of biological evolution and speciation.

Genetic drift refers to the phenomenon that if the population is too small and the number of individuals containing a certain gene in the population is very small, the gene may disappear in the population due to the sudden death of the individual or the failure to mate. In general, the smaller the population, the more significant the genetic drift.

Migration is when individuals with a gene have an unequal chance of migrating from one region to another, resulting in a change in gene frequency. For example, in a pair of alleles A and a, if individuals with the A gene migrate more to a new region than individuals with the A gene, then the gene frequencies of the new population established in that new region change.

Third, heritable variation

Heritable variation is the raw material of biological evolution, and heritable variation mainly comes from genetic mutations, genetic recombination, and chromosomal variation. In the theory of biological evolution, genetic mutations and chromosomal variations are often referred to collectively as mutations. A gene mutation is a change in the molecular structure of DNA, that is, a change in the order of deoxynucleotides within a gene. Genetic mutations are widespread. According to the conditions under which mutations occur, they can be divided into two categories: natural mutations and induced mutations. No matter what the conditions are, the mutation is random and has no directionality.

Chromosomal variation includes variation in chromosome structure and variation in the number of chromosomes, and variation in chromosome quantity includes the increase or decrease of individual chromosomes (non-integoid change) and exponential increase or decrease (integer change).

Among them, the variation of chromosome structure and the mutation of integeroids, because they destroy the balance of genetic material in organisms, are generally unfavorable to the life activities of organisms, and sometimes even fatal, and have little significance in the process of biological evolution. However, the change of chromosomal integer plurality does not destroy the balance of the original genetic material, which can strengthen some life activities of organisms, and has certain significance for the evolution of organisms, especially the formation of some new species, such as the formation of polyploids in nature.

Genetic recombination, on the other hand, refers to the exchange and combination of genes between chromosomes. It is due to the recombination and exchange of chromosomes in the same nucleus after replication during meiosis, resulting in a large number of gamete types with different gene combinations from the parents.

In addition, the combination of male and female gametes is random in the process of sexual reproduction, which further increases the type of variation in the traits of offspring. Genetic recombination actually includes the law of free combination of genes and the law of linkage and interchange of genes.

Both mutations and genetic recombinations are non-directive, with both advantages and disadvantages. But the advantages and disadvantages are not absolute, it depends on the environmental conditions. Environmental conditions have changed, and previously favourable variations may become unfavourable, while previously unfavourable variations may become favorable. Alleles are produced through genetic mutations and form a wide variety of genotypes through genetic recombination during sexual reproduction, resulting in a large number of heritable variations in the population.

Therefore, mutation is not directional, and mutation only provides raw materials for biological evolution, and cannot determine the direction of biological evolution. ”

Yang Mengmeng explained very quickly, and it only took a few minutes to say a large paragraph.

Luo Han was confused when he heard it, but Ye Xiuwen nodded, as if he understood.

"Black wolf? You actually understood? Luo Han said in surprise.

"I understand a rough idea, since the explanation of Meng Meng, I can hear that genetic mutations and evolution require an extremely long process, and it will not be so easy to change them. However, a series of genetic codes have been added to the gene chain of these organisms, so that they can change and metamorphose at a certain time and moment,...... Am I talking about that? Moe? ......”

Ye Xiuwen asked Yang Mengmeng, and Yang Mengmeng nodded and said, "You're right. There is nothing wrong with these animals themselves. Eating them is like eating genetically modified food. But the new question arises, who set the genetic code for them? And if you follow this genetic code. I'm afraid it won't be long before a supercivilization appears. ”

"Supercivilized?" Ye Xiuwen frowned.

"Yes, that's right, it's super-civilized. But I can't guess how far the genetic code of these creatures can go. I need to unravel their genetic strands. Yang Mengmeng said again, but her expression seemed to be a little embarrassed.

"What's wrong?" Ye Xiuwen saw Yang Mengmeng's embarrassed appearance and asked.

"I just got some biological samples. But the genetic code of the biological sample has been destroyed and cannot form a complete genetic chain. I need the most primitive genetic code, can you understand? Yang Mengmeng explained to Ye Xiuwen.

At this time, Luo Han also seemed to understand, and asked in surprise, "Do you want us to go back to that cave again?" ”

The arhats spread their hands, because it was indeed very dangerous, and if they went in again, there would be no casualties! ......