The Holliday model explains the mechanism of homologous recombination as a process by which genetic material is exchanged between two homologous DNA molecules. This model, proposed by Robin Holliday in 1964, was initially developed to explain recombination events during meiosis in fungi, but it also provides a fundamental framework for understanding recombination in prokaryotes and eukaryotes. Homologous recombination is essential for generating genetic diversity, ensuring accurate chromosome segregation, and repairing damaged DNA. According to the Holliday model, recombination begins when two homologous double-stranded DNA molecules align closely with each other. At identical positions on each DNA molecule, a single-strand break, or nick, occurs in one strand of each duplex. These nicks are introduced at corresponding sites, allowing the free ends of the broken strands to interact with the opposite homologous DNA molecule. The broken strand from one DNA duplex invades the other duplex and pairs with its complementary strand, displacing the original partner strand. This reciprocal exchange results in the formation of crossed strands between the two