Chapter 17, Problem 1MI

Which of the DNA molecules shown are recombinant?

Summary Introduction

A recombinant DNA is a type of DNA having new nucleotide sequences. Such type of DNA is formed by linking the fragments obtained from two or more different sources. The first breakthrough of the recombinant DNA technology was the bacterial enzymes that cut the double-stranded DNA. These bacterial enzymes are referred to as restriction enzymes.

Explanation of Solution

The provided figure shows four steps that are involved in the cloning of a gene. These steps include:

1. 1. Isolation of DNA which is to be cloned.
2. 2. Generation of DNA fragments by means of restriction enzymes or PCR.
3. 3. Insertion of DNA fragments into the cloning vector in order to generate a recombinant DNA molecule.
4. 4. Introduction of recombinant DNA into the new host cell which expresses the gene.

The DNA molecule shown in step 3 in the given figure is the recombinant DNA molecule. This step shows the vector along with an insert referred to as a recombinant DNA molecule. The bacterium produced, shown in step 4, is the recombinant organism.