The Variation Inside
Though it's long been assumed that each cell in a body contains the same basic genomic blueprint, research now suggests that genomes actually vary between cells in the same body.
The figure above comes from a study of copy number variation, in which stretches of DNA are repeated multiple times. In all 23 chromosomes (arrayed in radial form) researchers found copy number differences unique to each cell's physical origin (color coding). Brain cells, for example, had quite different genomes from lung cells.
Citation: "Extensive genetic variation in somatic human tissues." By Maeve O’Huallachain, Konrad J. Karczewski, Sherman M. Weissmand, Alexander Eckehart Urbana, and Michael P. Snyder. Proceedings of the National Academy of Sciences, Vol. 109 No. 44, 30 October 2012.
Image: O'Huallachain/PNAS (Larger image)