Question

It is said that humans can have up to 22 miles of DNA in their body, that’s if you attached it all.

Q: How can chromosomes hold so much DNA?

Answer 1

Non copy-write simple answer:

The unique structure of chromosomes keeps DNA tightly wrapped around spool-like proteins, called histones that support its structure. This allows our chromosomes to hold so much DNA, and without such packaging, DNA molecules would be too long to fit inside cells.

Answer 2

Chromosomal DNA is packaged inside microscopic nuclei with the help of histones. These are positively-charged proteins that strongly adhere to negatively-charged DNA and form complexes called nucleosomes. Each nuclesome is composed of DNA wound 1.65 times around eight histone proteins.