New Research Establishes that Intelligence Is Inherited from the Mother
New research suggests that people are born with conditioned genes that behave in different ways if inherited from your mother or your father––and mothers are responsible for transmitting intelligence to their children.
Researchers have known for years that intelligence has a hereditary component, but until recently, they believed a child’s intelligence depended on the father as well as the mother. In fact, several studies showed because intelligence genes are located on the X chromosomes (and mothers have two). Researchers at the University of Ulm, Germany, found that many genes, particularly those related to cognitive abilities, were on the X chromosomes.
The Medical Research Council Social and Public Health Sciences Unit in Glasgow, Scotland also conducted a study supporting this analysis. In 1994, researchers surveyed 12,686 young people between the ages of 14 and 22. In doing so, they took several factors––including the children’s IQ, race, education and socioeconomic status––into account. Researchers found that the best predictor of intelligence was the IQ of the mother and that the ratio of young people’s intelligence varied only an average of 15 points from their mothers.
However, genetics are not solely responsible for a child’s overall intelligence. Other studies indicate that mothers play a crucial, even intimate, role in a child’s emotional development, due in large part to physical and emotional contact. For examples, researchers at the University of Minnesota found that by the age of two, children who’ve formed strong attachments to their mothers have the capacity to play complex symbolic games. The findings suggest that a strong bond with their mothers fostered natural curiosity as well as the confidence to solve problems without exhibiting frustration or a change of heart. Mothers who involve themselves in their child’s problem-solving process also help to stimulate their child’s potential.
A study conducted at the University of Washington also demonstrated the importance of the emotional relationship for the development of the brain. Researchers have spent seven years analyzing the way mothers relate with their children. They found that by age 13, the hippocampus (which is located in the cerebral cortex and plays significant roles in the consolidation of information from short-term memory to long-term memory and spatial navigation) of children who benefit from the emotional support of their mothers is 10 percent greater than those of children whose mothers are emotionally distant.
Researchers conducted one of the first studies in this area at the University of Cambridge in 1984. The first experiment required scientists to create embryos of rats that only have the genes of the mother or the father. However, the embryos died before transfer to the uterus of adult female rats. In this way, researchers discovered that there are conditioned genes which only activate when inherited from the mother and that are crucial to the proper development of the embryo. They also found that a father’s genes are vital for the growth of the tissue that will form the placenta. Scientists hypothesized that genes essential to the development of the embryo would also have a significant impact brain function in the lives of animals and people. The problem, however, was proving their theory, because embryos with genes from only one parent died quickly.
Researchers found that embryos survived when normal embryonic cells were maintained. When they manipulated the rest, they created several genetically modified laboratory mice that did not develop in the same way. Mice that received an extra dose of maternal genes developed larger heads and brains, but smaller bodies. By contrast, mice that received an additional dose of paternal genes had smaller brains, but larger bodies. These findings helped researchers identify cells that contained only maternal or paternal genes in six different parts of the brain; these cells aid the development of advanced cognitive functions, such as eating habits and memory. Cells that have paternal genes tend to accumulate in the hypothalamus, amygdala, the preoptic area and the septum, which are part of the limbic system and influence functions such as sex, food, and aggression. Researchers have not found paternal genes in the cerebral cortex, where humans develop advanced cognitive functions such as intelligence, thought, language, and painting.
Researchers stressed that their findings should not discourage fathers. To solve any problem––even the simplest mathematical and physical ones––the limbic system must come into play because the brain works as a whole. If intelligence is linked to rational thinking from our mothers, they say, then it is also influenced by intuition and emotions that are contributed by our fathers. The impact fathers have on the development of their children––especially by being emotionally present––cannot be underestimated.