Chapter 13: the molecular basis of inheritance 3

DNA cloning, restriction fragment analysis, gel electrophoresis

what is DNA cloning?

• yields multiple copies of a DNA segment

• use of bacteria and their plasmids

what are plasmids?

• plasmids are small circular DNA molecules that replicate separately from the bacterial chromosome

how do restriction enzymes make a recombinant DNA?

• restriction enzymes cut DNA molecules at specific DNA sequences called restriction sites

• restriction enzymes cut DNA producing fragments with “sticky ends” that bond with complementary sticky ends of other fragments

• DNA ligase is an enzyme that seals the bonds between restriction fragments

what was the forensic evidence we looked at?

• an individual’s unique DNA sequence, or genetic profile, can be obtained by analysis of tissue or body fluids

what is restriction of fragment analysis?

• restriction fragments analysis, DNA fragments produces by restriction enzymes are sorted by gel electrophoresis

ex. sickle cell mutation destroys one of the restriction sites of Ddel enzyme

as a result digestion with this enzyme generates different fragments from the normal and sickle cell DNA