G
G
G
G
G
G
G
T T T T T T T T
T
T
T
T
T
T
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
C C C C C C C
C
C
C
C
C
G
G
G
T
T
T
A
A
A
C
C
C
G
G
T A
C
C
G
T
T
A
A
C G
T
A T
C
new strand new strand
The process by which the DNA double helix unwinds and makes an exact copy of itself.(Courtesy of Darryl Leja, NHGRI, National
Institutes of Health)