 |
|
|
Investigation of plasmids and antibiotic
resistance. |
|
Cohen needed to develop methods
for cloning in
bacteria. |
|
Began working with E.
coli bacteria to transform cell
plasmids. |
|
Antibiotic
resistance genes were used to take plasmids
apart and "recombine" (rDNA) them. |
|
Gobind Khorana's "paired" nucleotides in
single strings of DNA was
the key. The DNA enzyme ligase sealed the molecules
together.
Vittorio Sgaramella discovered that blunt DNA ends that lacked complementarity,
were joined by DNA ligase found in the T4 bacterial
virus |
|
Vittorio Sgaramella discovered that
blunt DNA ends that lacked complementarity,
were joined by DNA ligase found in the T4 bacterial
virus |
|
The terminal transferase enzyme was
discovered at the Oak Ridge National Laboratory.
R.H. Jensen used DNA ligase to clone nicks in rDNA,
but was not successful. |
|
Peter Lobban discovered manipulations
for permanent fusion of DNA fragments. Paul Berg
linked the E. Coli virus, lambda,
which sparked a biohazards
controversy |
|
"Palindrome" enzymes were discovered
by Werner Arber and Hamilton Smith. |
|
Historic meeting in Hawaii, where
many scientists discuss the possibility of cloning. |
|
Thoughts on how combining methods
might work |
|
May 1973 paper described results
of collaboration. |
|
DNA experiments were conducted by
Dr. Cohen and Annie Chang at Stanford, and by Herbert
Boyer at UCSF. They presented their paper to the
National Academy of Sciences, which was the basis
for the basic cloning patent. |
|
Eukarotic DNA
segments were propagated in E. Coli. |
|
Science isn't done in a vacuum.
If Cohen and Boyer hadn't discovered rDNA, someone
else would have. |
