Have you ever wondered which of the two parents transmits intelligence, or at least brain functions and abilities? Research suggesting that intelligence is inherited from the mother has recently come back into the spotlight, but some researchers dispute it.
Science shows that there are conditioned genes that behave differently depending on their origin. In fact, these genes have a kind of biochemical signature, which makes it possible to determine their origin and to know whether they are active in the cells of the offspring. Interestingly, some damaged genes only work if they come from the mother. If the same gene is inherited from the father, it is deactivated. Of course, other genes work the other way around and are only activated if passed down from the father.
We already knew that intelligence has a hereditary component, but a few years ago we thought that it depended largely on the father. However, several studies suggest that children inherit more intelligence from their mothers because genes for intelligence are located on the X chromosome. The mother’s genes go directly to the cerebral cortex, and from the father – to the limbic system. These new hypotheses coming from science should destroy the stereotypes that have been imposed on women for centuries.
One of the first studies in this area was conducted in 1984 at the University of Cambridge, and many studies have followed over the years. In these studies, brain coevolution and genomic conditioning were analyzed to develop the theory that maternal genes contribute most to the development of thought centers in the brain. It turned out that there are conditional genes that are activated only by inheritance from the mother, which are vital for the correct development of the embryo. Likewise, the father’s genes are essential for the growth of the tissue that makes up the placenta.
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The researchers believe they have observed that an extra dose of the mother’s genes will result in a larger head and brain, but a smaller body. On the other hand, those who received an extra dose of their father’s genes would have smaller brains and larger bodies. By analyzing these differences in depth, the researchers identified cells that contained only the mother’s or father’s genes in six different parts of the brain that control a variety of cognitive functions, from eating habits to memory.
In practice, during the first days of embryonic development, any cell can appear anywhere in the brain. However, as embryos mature and grow, cells that carry the father’s genes accumulate in certain areas of the emotional brain: the hypothalamus, amygdala, preoptic area, and septum. These areas are part of the limbic system, which is responsible for ensuring our survival and is involved in functions such as sex, eating and aggression. In contrast, the researchers found no father cells in the cerebral cortex, where the most advanced cognitive functions, such as intelligence, thinking, language and planning, develop.
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Scientists continued to study this theory. For example, Robert Lerke said that most of the intelligence of children depends on the X chromosome, and he also hypothesized that because women have two X chromosomes, they are twice as likely to inherit traits related to intelligence. Recently, researchers at the University of Ulm in Germany studied genes associated with brain damage and found that many of them, especially those related to cognitive abilities, are on the X chromosome. Therefore, it will not be a coincidence that intellectual disability is 30%. It is more common in men.
But perhaps one of the most interesting findings comes from an analysis conducted by the Medical Research Council in Glasgow, Scotland. In this study, researchers interviewed 12,686 young people between the ages of 14 and 22 each year. They took into account several factors, from skin color to education to socioeconomic status, and noticed a trend: the best predictor of a child’s intelligence was the mother’s IQ. Indeed, the relationship between the intelligence of the youth and the intelligence of the mother differed by an average of only 15 points.
However, few serious media outlets acknowledge that saying that intelligence genes are passed down primarily on the X sex chromosome is very different from saying that a woman will be responsible for passing on cognitive abilities to her child because she has two chromosomes. Although some studies have shown that a child’s intelligence comes from the mother, their findings have since been overturned by new research. This is explained especially by the fact that research is in full expansion in the field of genetics.
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