You perform an experiment where you isolate chromatin from sea urchin sperm cells, then partially digest with microococcal nuclease [my-kruh-KOK-kuhl NOO-klee-ays]. When you purify the DNA away from the chromatin proteins and run your DNA on a gel, you find that your DNA fragments have lengths that are multiples of 260 base pairs. What organizational element of chromatin leads to this digestion pattern?
NUCLEOSOME