In 1975, the Asilomar Conference on Recombinant DNA was organized by Paul Berg, a pioneer of recombinant DNA technology, at a conference center at Asilomar State Beach in California. Physicians, scientists, lawyers, ethicists, and others gathered to draft guidelines for safe applications of recombinant DNA technology. These general guidelines were adopted by the federal government and are still in practice today. Consider the implications of recombinant DNA as a new technology. What concerns might the scientific community have had then about recombinant DNA technology? Might those same concerns exist today?

What are the advantages of using a restriction enzyme whose recognition site is relatively rare? When would you use such enzymes?

Restriction sites are palindromic; that is, they read the same in the 5' to 3' direction on each strand of DNA. What is the advantage of having restriction sites organized this way?

List the advantages and disadvantages of using plasmids as cloning vectors. What advantages do BACs and YACs provide over plasmids as cloning vectors?

In the context of recombinant DNA technology, of what use is a probe?

If you performed a PCR experiment starting with only one copy of double-stranded DNA, approximately how many DNA molecules would be present in the reaction tube after 15 cycles of amplification?

In a control experiment, a plasmid containing a HindIII recognition sequence within a kanamycin resistance gene is cut with HindIII, re-ligated, and used to transform E. coli K12 cells. Kanamycin-resistant colonies are selected, and plasmid DNA from these colonies is subjected to electrophoresis. Most of the colonies contain plasmids that produce single bands that migrate at the same rate as the original intact plasmid. A few colonies, however, produce two bands, one of original size and one that migrates much less far down the gel. Diagram the origin of this slow band as a product of ligation.