DNA is tightly packed in the nucleus. DNA molecule wraps around histone proteins to form tight loops called nucleosomes. Nucleosome is a structure formed by two molecules of each H2A,H2B,H3&H4. They associate to form an elliptical bead like structure. One nucleosome is covered by a H1 protein and 1 3/4 of DNA wraps around one nucleosome. These nucleosomes coil and stack together to form fibre called chromatin which constitutes the genetic material inside the nucleus.
