Final answer:
Linker DNA serves as a linker in the core complex of chromatin, connecting nucleosomes and aiding DNA compaction.
Step-by-step explanation:
In the core complex of chromatin structure, the linker DNA serves as a linker. In the first level of compaction, DNA wraps around a core of eight histone proteins to form a nucleosome. The beadlike structure of the histone-DNA complex is approximately 10 nm in diameter and is interconnected by linker DNA, which aids in the packing of DNA and compacts it to about seven times shorter than the double helix would be on its own. This structural organization contributes to the higher-order packing of the DNA within the cell nucleus, which is essential for orderly DNA replication and gene expression.