Twin studies show that individual differences in human intelligence can largely (50%–80%) be explained by genetic influences making intelligence one of the most heritable traits. However, present GWAS studies can capture less than half of this heritability (21%–22%). Each gene has a small effect on intelligence. Ninety-five percent of the genetic variants are located in intronic and intergenic regions and might have a gene regulatory function. Only a very small proportion of associated SNPs (1.4%), are located in DNA fragments that are translated into protein.
The cost of embryo selection is modest, at $1500 + $200 per embryo, with the sequencing cost projected to drop rapidly. Embryo selection cost will drop in future. Selecting the most intelligent embryo out of a few dozen combined with some targeting editing could nearly guarantee IQ over 125 and a 25-30 IQ point increase on average.
The maximum amount of IQ gain if screening allowed for optimal selection
Most of the intelligence associated genes are implicated in early, most probably prenatal development, with some genes essential for synaptic function and plasticity throughout life. This means the main genetic enhancement of human intelligence would have be made while the person is an embryo. The changes have to be made before the brain develops.
Birth length/weight and longevity show robust polygenic correlations with cognitive performance which implies that overall healthy development is required for optimal cognitive function.
Genes associated with educational attainment and intelligence preferentially express together in nervous tissue.
There is a cellular basis of human intelligence. Higher IQ scores associate with larger dendrites, faster action potentials during neuronal activity and more efficient information tracking in pyramidal neurons of temporal cortex.
Future Predictions of Human Genomes Sequenced and Analyzed
In 2018, the world’s largest genetic research center, the Beijing Genomics Institute based in Shenzhen, held an estimated 40 million people’s DNA samples. Called the “Gene Factory”, BGI’s campus hosts armies of students, who run several massive projects to “sequence the world”. They are on a quest to map the DNA of all known plants and animal species on Earth.
By providing its sequencing services to health and biotech groups in more than 60 countries, BGI is making a winning bet on the future: reading our genes, on a global scale, to crack illness, famine, evolution – and the secrets of human intelligence.
By 2025, between 100 million and 2 billion human genomes could be sequenced.