DNA molecules from two different
sources (blue and
red) are
cut with the same restriction
endonuclease enzyme, in
this case
EcoRI. This leaves fragments with
identical
overhanging ~~TTAA-5' "sticky
ends". Because the EcoRI
site is a palindrome, tails from the blue
and red DNAs are
complementary and can come together in new combinations
("recombination"). Gaps
in the sticky ends are sealed with the enzyme DNA ligase.
