For this to happen the DNA must replicate itself exactly. When DNA replicates itself and the cell divides both of the new cells that are produced contain the exact same DNA (barring mutations) which means both new cells can code to make the same proteins.
Americium was first produced in 1944 by the group of Glenn T. Seaborg at the University of California, Berkeley. Although it is the third element in the transuranic series, it was discovered fourth, after the heavier curium.
The separation of curium and americium was so painstaking that those elements were initially called by the Berkeley group as pandemonium (from Greek for all demons or hell) and delirium (from Latin for madness). Initial experiments yielded four americium isotopes: 241 Am, 242 Am, 239 Am and 238 Am.