When comparing the genomes of two different organisms, single letter changes—changes in the order of the genomes’ three billion adenine (A), cytosine (C), guanine (G), and thymine (T) base components—can be found every few thousand letters, often in consecutive sets easily rendered in blocks. This image represents these blocks in the genetic profile of three different populations: the top row shows a group of Yorubans, from western Africa; the middle row depicts groups with western European ancestry; and the bottom row represents a group of Japanese and Han Chinese. “The vertical height of each column is proportional to the number of people in each group that has one set of changes or another,” Fry explains, “and the colors in each row depict one of two variations possible for each single letter change, the most common in dark red and the less common in a paler color.”
Gallery label from Design and the Elastic Mind, February 24–May 12, 2008.
