While a child can be a spitting image of either parent, is it then possible to similarly inherit their smarts from just one parent too?
It is not uncommon for parents to wonder whom their child takes after. While they want the good traits to be theirs, they will not hesitate to blame the lesser traits on their partner. While a child can be a spitting image of either of their parents, is it then possible to similarly inherit their smarts from just one parent too? There have been research claims that children may be getting their intelligence from just their mother. A blog post from Psychology Spot, which has now been taken down, stated that a mother's genetics determines how clever her children are.
The Independent reported, based on the blog post, that women are more likely to transmit intelligence genes to their children because they carried on the X chromosome. Since women have two X chromosomes and men only have one, it seemed to be more likely. Intelligence seems to be a part of genes known as "conditioned genes" which usually come from the mother. So, researchers carried out an experiment on mice to identify cells that contained only maternal or paternal genes in the parts of their brains that controlled different cognitive functions, from eating habits to memory.
When the six different parts of the mouse brains were studied, it was found that the paternal genes had accumulated in parts of the limbic system, which deals with functions such as sex, food, and aggression. On the other hand, in the cerebral cortex, which is where the most advanced cognitive functions such as reasoning, thought, language, and planning happens, no paternal cells were found. It was found that with an extra dose of maternal genes, mice developed bigger heads and smaller bodies. It was the other way round when it came to extra doses of paternal genes.
To extrapolate these findings to humans, the researchers from Medical Research Council Social and Public Health Sciences Unit in Glasgow, decided to interview kids every year from the age of 14-22, to find out if their IQs tend to be similar to that of their mothers. They had also taken into account various factors like education and socioeconomic status. The researchers found that the best predictor of intelligence was the children's mothers, reported Birmingham Live. There were only around 15 points of difference between that of the mother and the child.
But intelligence is not something that only depends on genetics. It has been well-established through research that intelligence is a mixture of a lot of factors. "It’s layer upon layer upon layer of interacting pieces," wrote Emily Willingham wrote for Forbes. "So no. Not just your mother. Not just the X chromosome. Not even just genes." A part of our intelligence is inherited but that is also broken into genetic variants which in turn are influenced by a host of "environmental factors, both in its immediate molecular world and inputs to the whole organism, that will influence function." So a combination of genes and the environment we are exposed to have a bearing on our intelligence.
KQED also "debunked" the idea that only one parent can contribute to a child's intelligence. Reiterating that "hundreds or even thousands of genes contributing to intelligence have only a small effect on overall IQ", the site even reached out to a senior research fellow at the University of Glasgow, Geoff Der. He clarified that the blog post seemed to be referring to research that set out to find the impact breastfeeding would have on intelligence in children.
The research found that while breastfeeding has no bearing on the intelligence of a child, "maternal IQ has the largest independent effect" with factors such as maternal education, age, family poverty, and birth order "all making independent contributions for most outcomes." The paternal intelligence was not even considered since the data was unavailable.