A team led by researchers from the National Institute on Aging’s (NIA's) Laboratory of Neurogenetics conducted a genome-wide association study using genotype and transcriptome* expression arrays to study gene expression in the human brain. Working with brain tissue from 193 people age 65 and older who died free from neurological disease, the scientists found that 58 percent of more than 24,000 measured transcripts were expressed in the brain in at least 5 percent of the samples; of those transcripts, 21 percent had profiles suggesting that their expression was under genetic influence. By counting the number of transcripts, researchers may be able to determine what genes are active, or expressed, in brain cells and how genetic variations may contribute to a disease. Made possible through tissue donated by NIA-funded Alzheimer’s Disease Centers, this highly collaborative effort has made the database and most of the DNA samples accessible online to enable future studies regarding risk for common neurological diseases and which areas of the genome play a role. The research was published in Nature Genetics.
*The transcriptome is a collection of all the gene transcripts found in a given cell. Transcripts, or messenger RNA (mRNA) molecules, deliver instructions for making proteins. By analyzing the transcriptome, scientists can learn when and where a gene is turned on or off in various types of cells and tissues.