"It was once thought that each cell in a person's body possesses the same DNA code and that the particular way the genome is read imparts cell function and defines the individual. For many cell types in our bodies, however, that is an oversimplification. Studies of neuronal genomes published in the past decade have turned up extra or missing chromosomes, or pieces of DNA that can copy and paste themselves throughout the genomes.
"The only way to know for sure that neurons from the same person harbor unique DNA is by profiling the genomes of single cells instead of bulk cell populations, the latter of which produce an average. Now, using single-cell sequencing, Salk Institute researchers and their collaborators have shown that the genomic structures of individual neurons differ from each other even more than expected. The findings were published November 1 in Science.
"Contrary to what we once thought, the genetic makeup of neurons in the brain aren't identical, but are made up of a patchwork of DNA," says corresponding author Fred Gage, Salk's Vi and John Adler Chair for Research on Age-Related Neurodegenerative Disease.
"There's a lot more work to do to really understand to what level we think the things we've found are neuron-specific or associated with different parameters like age or genotype," he says."
http://medicalxpress.com/news/2013-11-patchwork-genetic-variation-brain.html
McConnell et al. (2013). "Mosaic copy number variation in human neurons." Science, 342: 632-637. Abstract.
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