Final answer:
After double-strand break occurs, sections of DNA around the blunt ends of the break are cut waste in a process called resection. A overhanging staggered end of the broken DNA molecule then "invades" a similar/identical DNA molecule that is not broken.
Step-by-step explanation:
After double-strand break occurs, sections of DNA around the blunt ends of the break are cut waste in a process called resection. A overhanging staggered end of the broken DNA molecule then "invades" a similar/identical DNA molecule that is not broken.
These overhangs, known as "sticky ends", can come back together by hydrogen bonding with complementary overhangs on a piece of DNA cut with the same restriction enzyme. The process of forming hydrogen bonds between complementary sequences on single strands to form double-stranded DNA is called annealing. Addition of an enzyme called DNA ligase permanently joins the DNA fragments when the sticky ends come together.
In summary, after double-strand break (DSB) occurs, the blunt ends are cut waste and the overhanging staggered ends of the broken DNA molecule "invade" a similar/identical DNA molecule, forming sticky ends, which can be joined together through annealing and the action of DNA ligase.