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.
Berzelius and Klaproth are major figures in the history of chemistry. In addition to their other achievements Berzelius discovered selenium in 1817 and thorium in 1828 while in 1789 Klaproth discovered both uranium and zirconium. Carl G. Mosander, who worked closely with Berzelius, prepared metallic cerium in 1825. First he reacted cerium sulfide with chlorine, yielding anhydrous cerium chloride. He reduced the chloride with potassium, forming potassium chloride and metallic cerium.