You have a 1500 bp long cDNA in a plasmid vector. You want to sequence the cDNA insert. (You know the sequence of the vector.) The sequence reads you can obtain are only 1000 bp long. How can you get the sequence of the entire cDNA insert

By designing primers complementary to each end of the insert, then use PCR and finally sequence the PCR product. Alternatively, it is also possible to construct a library from the 1500 bp insert and the resulting overlapping contigs can be sequenced  

Explanation:

Polymerase chain reaction (PCR) is a widely used technique in molecular biology that enables the amplification of specific DNA fragments (approximately 1000 pb) which are subsequently sequenced. This technique is based on the repetition of successive amplification cycles, for which it is required to obtain a pair of primers complementary to the sequence of interest and a DNA polymerase that synthesize both DNA strands. Finally, PCR products can be sequenced directly (i.e., without cloning). On the other hand, a cloning library is a collection of DNA fragments cloned into appropriate vectors. Subsequently, these fragments can be identified by sequencing.