Is the childs IQ inherited from mother or father?

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 Is the childs IQ inherited from mother or father?


Is intelligence gene on X chromosome?

In fact, as early as 1972, some people in the scientific community put forward the idea that intelligence gene is on the X chromosome. At that time, gene sequencing had not yet been realized, and the researchers only made this guess based on statistical differences in IQ between men and women. Because they found that although the statistical distribution of IQ of men and women is Gaussian distribution, the variance of IQ distribution of men is larger, that is to say, the proportion of men with extremely high and low IQ is higher than that of women. It seems that there is not only a close genetic relationship between mental retardation and mental retardation. This conjecture was gradually confirmed by experiments.

At the beginning of this century, with the vigorous development of human genome project, more and more gene sequence codes have been cracked. Scientists have found that at least 40% of the nearly 1000 protein coding genes on the X chromosome are expressed in the brain, which is higher than that on the autosomal chromosome and far more than on the Y chromosome. In other words, X chromosome has a great effect on brain structure, cognitive ability, intellectual development and so on. For boys, their only X chromosome comes from their mother. In other words, theoretically speaking, the genetic effect of mother on sons intelligence should be huge, but why is there no significant correlation between IQ statistics? What is the matter?

How do genes on the X chromosome determine brain structure?

This involves two concepts: X-inactivation and chromosome recombination in meiosis.

On the other hand, meiosis is a special way of cell division. When a sex cell divides, the chromosome is duplicated only once, and the cell divides twice in succession. In this way, the number of chromosomes in the cell is halved. Women have two X chromosomes, one X in each egg cell during meiosis. When a cell divides continuously, chromosomes will be recombined many times. Two different x staining from parents will exchange some genes in the same position, which will make the X chromosome of each egg cell mixed with the genes of the original two X chromosomes.

So, when the son got the X chromosome from his mother, it was the result of meiosis and chromosome recombination, a mixture of X chromosomes from his grandparents. The X chromosome used by his mother when compiling the brain was also randomly selected. The brain structure of mother and son may be completely different, or there may be a great degree of similarity. The most likely result is that there are some similarities and some differences. The design of nature is so ingenious. Although the mother should take the main responsibility for the genetic problem of sons intelligence, the intelligence level of his son can not be predicted by the intelligence of his mother.

The evolution of human intelligence and genius gene

The concentration of intelligence genes on the X chromosome sounds like a disadvantage for men, but many scientists believe that this is actually a big advantage in the evolution of human intelligence. Professor Gillian Turner of the University of Newcastle, Australia, believes that human intelligence evolves faster than any other genetic trait. If you want to spread a gene as quickly as possible, it is the wisest choice to put it on the X chromosome. X chromosome as a sex chromosome has a history of more than 300 million years. Most of its genes have been well preserved, and has always been the dominant position on the sex chromosome. Therefore, it has been speculated that the evolution on the X chromosome does not mainly rely on the production of new genes, but largely on the generation of new combinations of old genes.

Many scientists also speculate that genius genes are also closely related to the X chromosome. The picture below represents such a simple model of the emergence and spread of gifted genes. There are only six genes in this model, all on the X chromosome. After meiosis on the X chromosome, the first generation of mothers produced a gifted gene combination, the son of all a gene. This son married another woman and had two children, and his genius genes could only be passed on to his daughter, not to his son. But his daughter remarried, because of the chromosome recombination (x position) in meiosis, the genius gene combination was broken up, all the fourth generation were mediocre, but the gene was still spreading, looking forward to the opportunity of the genius combination again. So, although the gene of genius can continue, the emergence of genius is just an accident. If it is true that the gene of genius still needs to be inherited by daughters, then all talented men should have daughters. Otherwise, if the genes are broken in their sons, what a great loss to human beings. Source: observer.com editor in charge: Wu Yanli_ NBJS6202

Many scientists also speculate that genius genes are also closely related to the X chromosome. The picture below represents such a simple model of the emergence and spread of gifted genes. There are only six genes in this model, all on the X chromosome. After meiosis on the X chromosome, the first generation of mothers produced a gifted gene combination, the son of all a gene. This son married another woman and had two children, and his genius genes could only be passed on to his daughter, not to his son. But his daughter remarried, because of the chromosome recombination (x position) in meiosis, the genius gene combination was broken up, all the fourth generation were mediocre, but the gene was still spreading, looking forward to the opportunity of the genius combination again. So, although the gene of genius can continue, the emergence of genius is just an accident.

If it is true that the gene of genius still needs to be inherited by daughters, then all talented men should have daughters. Otherwise, if the genes are broken in their sons, what a great loss to human beings.