Gene Identified that Influences Memory for Events

Scientists have found that a common gene variant influences memory for events in humans by altering a growth factor in the brain's memory hub. Their finding was reported in the January 24, 2003, issue of Cell.

Researchers at the US National Institute of Mental Health (NIMH, Bethesda, MD, USA) explored the consequences of a tiny variance in the BDNF gene. People inherit two copies of the gene, one from each parent, in either of two versions. The more common version, called "val,” contains valine, while the other version, called "met,” contains the amino acid methionine. Slightly more than a third of all people inherit at least one copy of the "met” version, which the researchers have now found linked to poorer memory.

When the researchers tagged gene variants with green fluorescent protein and introduced them into cultured neurons, they discovered that "val” BDNF spreads throughout the cell and into the dendrites that form synapses, while "met” BDNF mostly clumps inside the cell body without being transported to the synapses. To regulate memory, BDNF must be secreted near the synapses.

"We are finding that this one amino acid substitution exerts a substantial influence on human memory, presumably because of its effects on the biology of the hippocampus,” said Daniel Weinberger, M.D., one of the NIMH researchers.