Genetic mutations that damage health can also make people stupid

found that smart people have fewer DNA mutations that impair intelligence and overall health.
photo source: Samuel Corum/Anadolu Agency/Getty images
what makes some people smarter than others? A genetic analysis of Scottish families in the UK shows that smart people have fewer DNA mutations that impair intelligence and overall health, rather than more genetic mutations that make them smarter. The results have been published in the life sciences preprinted
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there is no doubt that intelligence depends in part on the environment in which people grow up. For example, well-no-nutrition children who grew up in safe, untamed and promoting environments performed better on average on intelligence tests than poor children.
, however, the human gene also plays a role. Studies of twins have shown that 50 to 80 percent of the general intellectual differences between humans may be due to genes. However, finding genetic variants that affect intelligence has proved tricky.
to date, studies of the DNA of thousands of unrelevant individuals have shown that only about 30 percent of the intellectual differences are genetic. The huge discrepancy between twin studies and genomic results has become a known genetic absence mystery.
, a team that included David Hill, a researcher at the University of Edinburgh, analysed data from 20,000 people. The team used statistical methods to explore how rare genetic mutations shared by most members of a family can affect intelligence.
researchers found that rare genetic variations missed by other studies explained the differences between the two types of studies. In theory, smart people may be smart because they have benign genetic variants that improve intelligence. Benign genetic variants were expected to spread through natural selection, making them common in a population. Hill's research shows that extremely rare genetic variants play an important role. They are more likely to be slightly harmful and unhealthy mutations. Evolution is not very good at eliminating such mutations, so they accumulate and produce "mutation loads" that vary from person to person. People's intelligence depends on their mutation load. (Source: Science Network Xu Xu)