Key steps shared by different models Alignment(结盟) of two homologous DNA molecules Introduction of breaks in the dna Formation of initial short regions of base pairing between the two recombining DNA molecules, strand invasion Movement of the Holliday junction branch migration >Cleavage of the holliday junction resolution➢ Alignment (结盟) of two homologous DNA molecules. ➢ Introduction of breaks in the DNA ➢ Formation of initial short regions of base pairing between the two recombining DNA molecules: strand invasion ➢ Movement of the Holliday junction: branch migration ➢ Cleavage of the Holliday junction: resolution Key steps shared by different models