New York, May. 13 (PTI): A number of genes passed on by parents have a role throughout life -- from determining brain volume to the degree of age-related decline of cranial matter, a research headed by an Indian doctor has found.

A team of researchers from Boston University led by Sudha Seshadri found that 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, the New Scientist reported.

The researchers assessed the cognitive abilities of 705 healthy adults with standard tests and used MRI scans to measure the volume of their brains. They 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," said Seshadri who completed her MBBS from the Christian Medical College, Vellore.

She joined the Boston University School of Medicine's Department of Neurology in May 2001 as Assistant Professor in the Department of Neurology.