Final answer:
Histones organize replicated DNA into nucleosomes, compacting the DNA and forming the structure of chromatin. Through further compaction and the addition of non-histone proteins, chromatin is organized into fully compacted chromosomes seen in the metaphase of cell division.
Step-by-step explanation:
During DNA replication, histones play a critical role in the organization of DNA into a compact structure known as chromatin. Short stretches of the DNA double helix wrap around a core of eight histone proteins to form a nucleosome, which then compacts the DNA about seven times shorter than its extended form. The nucleosomes are connected by linker DNA, and this 'beads on a string' structure is subsequently coiled into a 30-nm chromatin fiber which further condenses the DNA. This process continues until eventually, the chromosome reaches its most compact structure during the metaphase stage of cell division.
The histone assembly after DNA replication involves the organization of the newly replicated DNA into nucleosomes to begin the compaction process necessary for the proper segregation and functioning of the chromosomes within the cell. Histones are evolutionarily conserved and basic amino acids-rich proteins forming an octamer that associates tightly with the negatively charged DNA, facilitated by their positive charge. These nucleosomes then associate with various non-histone proteins to form higher-order structures and eventually the highly compacted chromosomes that are characteristic of metaphase.