FIGURE 2: Changes in chromatin structure during aging.

(A) Nucleosome occupancy is reduced by half over the entire yeast genome in old cells, while positioning of nucleosomes becomes fuzzier in old cells. The schematic at the bottom indicates that most nucleosome positions are retained within the population of old cells, while each cell has only half of the number of nucleosomes. The dotted lines indicate that the nucleosomes in old cells can move to the left or right of the positions in young cells in the absence of steric hindrance from adjacent nucleosomes.

(B) Some nucleosomes move significantly during aging, as shown by the nucleosome positioning tracks above and the schematic below.