Nucleosomes and their linker DNA coil into a 30 nm fiber. How much shorter is the chromosome then?

1. Packing happens in stages, and each stage compacts the DNA further. 2. The first stage wraps DNA on histones into nucleosomes. 3. That stage alone leaves the molecule about seven times shorter than the extended helix. 4. The second stage coils the string of nucleosomes into a 30 nm fiber. 5. After that coiling the chromosome is about 50 times shorter than the extended form. 6. Answering 7 times stops at the first stage and never applies the coiling. 7. The 10 nm figure describes the width of a nucleosome bead, not any shortening factor. 8. A third stage using fibrous proteins packs it further still, so no single number covers the whole job. _Source: OpenStax Biology 1e (CC BY 4.0), Chs 10 and 11, section 10.1 Cell Division_