In 1953, James Watson (1928–) and Francis Crick (1916–2004) proposed their double helix model for the three-dimensional structure of DNA. They correctly deduced that the genetic information was encoded in the form of the sequence of nucleotides in the molecule. With their landmark discovery began an era of molecular genetics in biology. Eight years later investigators cracked the genetic code. They found that specific trinucleotide sequences—sequences of three nucleotides—are codes for each of 20 amino acids, the building blocks of proteins.
Racenis, Patricia V. “Deoxyribonucleic acid (DNA).” The Gale Encyclopedia of Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner. 5th ed. Farmington Hills, MI: Gale, 2014. Science in Context. Web.
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