 The RecBCD pathway is the main recombination pathway used in many bacteria to repair double @-@ strand breaks in DNA , and the proteins are found in a broad array of bacteria . These double @-@ strand breaks can be caused by UV light and other radiation , as well as chemical mutagens . Double @-@ strand breaks may also arise by DNA replication through a single @-@ strand nick or gap . Such a situation causes what is known as a collapsed replication fork and is fixed by several pathways of homologous recombination including the RecBCD pathway . 
