Question

A sequence of DNA ( 3' CCTCCGATGA 5' ) is used as a TEMPLATE strand for dideoxy sequencing. The products are made and the products are run in 4 different lanes (labelled "A", "G", "C", and "T") of an electrophoretic gel. Which lane will contain the product that ran furthest down the gel

Answer 1

The reaction with adenine dideoxynucleotides will run furthest in the gel

Step-by-step explanation:

In dideoxy sequencing (also known as Sanger sequencing), the DNA template is used to run four different reactions in which only one class of dideoxynucleotide (ddNTP) is added. These four different ddNTPs (i.e., ddATP, ddCTP, ddTTP or ddGTP) act as terminators during DNA synthesis. Moreover, the additional factors required for DNA synthesis including standard deoxynucleotides (dNTPs), DNA polymerase and site-specific primers are added in equal volumes to prepare these four different reactions. Thus, during electrophoresis, the sizes of the DNA bands will depend on the specific ddNTP used in each reaction. In this case, the reaction containing ddATP (capable of terminating DNA synthesis at the 5' end) will run furthest in the gel.