From where the intelligence came from?  …

A study by psychologist Robert Sternberg concluded that the skills and knowledge you have are the results of your family. However, it is not a genetic relation, but rather, an educational one. Children inherit practical intelligence, which is the knowledge that comes from the way your parents communicate with you.

There are a lot of theories regarding it.........But two are the most popular based on biological and genetical studies

• A number of genes that affect intelligence could be located on the X-chromosome. Since males have only one X and other inherit it from their mothers, their intelligence might be more closely linked to their mothers than to their fathers.
• Mitochondria are inherited (almost) exclusively from the mother. Though mitochondrial genes might not seem to be genes “for” intelligence, brains are voracious consumers of metabolic energy - which is supplied by mitochondria. Better mitochondria are likely to translate to better brain function.