3.3.2 Restriction Enzymes

DNA fragments are generated by using enzymes called restriction endonuclease. These enzymes can recognize a specific site on DNA known as restriction sites.  These sites are characterized by having a few numbers of bases arranged in palindrome arrangement on the DNA molecule i.e. it can be read from right to left in one DNA strand and from left to right on the opposite strand.  There are a number of restriction enzymes each can act on a specific site. There are enzyme types that cut the restriction sites in a staggered way producing complementary-single- stranded tails. The resulting single-stranded tails can anneal with complementary tails from other DNA fragments to form recombinant DNA molecules.