It seems you owe your brains to your parents. Inherited variations in two genes are linked with reasoning, memory and brain volume. One of the genes is also involved in Alzheimer’s disease, which raises the possibility that other genes with a role in healthy people may also be implicated in diseases of old age.

Sudha Seshadri at Boston University and colleagues assessed the cognitive abilities of 705 healthy adults with standard tests and used MRI scans to measure the volume of their brains. The researchers also scanned 100,000 single-nucleotide polymorphisms – small variations in the genome sequence – in participants’ DNA for links to mental performance.

The strongest links were in the genes SORL, involved in abstract reasoning and the processing of amyloid protein in Alzheimer’s disease, and CDH4, which seems to predict brain volume.

“A number of these genes have a role throughout life, perhaps in determining brain volume or the degree of age-related decline,” Seshadri said at an American Academy of Neurology meeting in Boston on 2 May.