What are sticky and blunt ends of DNA molecules?

The sticky or blunt ends refer to the properties of the end of DNA molecules, which are commonly generated by restriction enzymes that cut the DNA.

A straight cut of restriction enzymes generates blunt ends, where both strands terminate in a base pair. Blunt ends are also called non-cohesive ends, since there is no unpaired DNA strand fleeting at the end of DNA.

The sticky ends, a.k.a. cohesive ends, have unpaired DNA nucleotides on either 5’- or 3’- strand, which are known as overhangs. These overhangs are most often generated by a staggered cut of restriction enzymes. Sticky ends are generally more desired in cloning technology where a DNA ligase is used to join two DNA fragments into one, because the yield and specificity of ligation using sticky ends is significantly higher that with blunt ends.