History of DNA as genetic material

Gregor Mendel

• mid 1800’s

• studied pea plants

• proposed by heritable units/molecules/”factors”

• “factors” became genes

Frederick Griffith

• 1928

• provided direct evidence for “factors” buy transforming/changing the traits of Bacteria

Oswald Avery, Maclyn McCarty, Colin MacLeod

• 1944

• 1st to show DNA transformative factor

  • Protease treated “s” extracted + Live “R”

  • RNAse treated “s” extracted + Live “R”

  • DNAse treated “s” extracted + Live “R”→ mice live (sole survivor)

Alfred Hershey + Martha Chase

• 1952

• additional evidence for DNA as genetic material

• Radioactively labelled bacteriophage

  • Labelled proteins w/ S-35 (sulfur-35)

  • DNA w/ P-32 (phosphorus-32)

• Infected Bacteria w/ Phage

• Followed Radioactive Probe + found DNA substance that viral genetic material