DNA Lab Report What is DNA? What do the letters stand for? What is it composed of? Where is it found? What is it shaped like? Answer in full sentences. DNA Timeline DNA has been researched by scientists for over 100 years, even before some knew what it was. From determining the complementary base pairs to the iconic double helix to using DNA to decode the human genome, DNA has had many milestones. Using information from the text and online research, arrange these DNA milestones in chronological order by putting a number from 1 (the earliest) to 11 (the most recent) next to each milestone. The Human Genome project was completed. Linus Pauling proposed the triple helix. Mendel published his study of pea plants to determine the laws of inheritance. Hershey and Chase confirmed that DNA is genetic material using their famous density gradient centrifuge technique. Matthew Stanley Meselson and Franklin William Stahl proved semi conservative replication, showing how DNA unzips to split into two pieces before replicating. Rosalind Franklin used x-ray diffraction to determine the structure of DNA. She proposed a helical structure with the phosphate groups on the outside. Thomas Hunt Morgan published findings from an examination of genetics of fruit flies and determines chromosomes are the basis for heredity. Arthur Kornberg discovered DNA polymerase, the molecule that is responsible for assembling parts of DNA during replication. Reverse Transcriptase was discovered by David Baltimore and Howard Martin Temin. Marshall Warren Nirenberg deciphered the genetic code Alec Jeffreys developed DNA fingerprinting.