In vitro DNA amplification is done by

(D) Polymerase chain reaction # DNA amplification is done by PCR> Blotting technique Following gel electrophoresis, probes are often used to detect specific molecules from the mixture. However, probes cannot be applied directly to the gel. The problem can be solved by three types of blotting methods: Southern blotting, Northern blotting and Western blotting. Southern blotting is a technique for detecting specific DNA fragments in a complex mixture. Northern blotting is used for detecting RNA fragments, instead of DNA fragments. Western blotting is used to detect a particular protein in a mixture. The probe used is therefore not DNA or RNA, but antibodies. The technique is also called "immunoblotting" PCR: In vitro Techniques such as the polymerase chain reaction allow the amplification of specific DNA sequences so that minute quantities of foreign nucleic acids can be recognized in host specimens. Recombinant DNA refers to a collection of techniques for creating (and analyzing) DNA molecules that contain DNA from two unrelated organisms. One of the DNA molecules is typically a bacterial or viral DNA that is capable of accepting another DNA molecule; this is called a vector DNA. The other DNA molecule is from an organism of interest, which could be anything from a bacterium to a whale, or a human. Combining these two DNA molecules allows for the replication of many copies of a specific DNA. These copies of DNA can be studied in detail, used to produce valuable proteins, or used for gene therapy or other applications. Electrophoresis, also called cataphoresis, is the motion of dispersed particles relative to a fluid under the influence of a spatially uniform electric field. This electrokinetic phenomenon was observed for the first time in 1807 by Reuss , who noticed that the application of a constant electric field caused clay particles dispersed in water to migrate. It is ultimately caused by the presence of a charged interface between the particle surface and the surrounding fluid.