Sanger sequencing is a process used to determine the precise order of the nucleotides in a given DNA fragment. It is also known as the chain termination method. Sanger sequencing consists of 6 steps:

• The dsDNA (double-stranded DNA) is denatured into two ssDNA (single-stranded DNA) using heat.
• The temperature is lowered and a DNA primer that is complementary to the template DNA is attached to one end. This marks where the sequencing will begin. 
• The fragments are added to 4 polymerase solutions. Each solution contains the 4 types of bases (dNTPs) but only one type of termination nucleotide (ddNTP). 
• The DNA synthesis reaction gets initiated and the complementary chain grows until a termination nucleotide is randomly introduced.
• The resulting DNA fragments are denatured to obtain a series of ssDNA of various lengths.
• Gel electrophoresis is used to separate the denatured fragments and determine the sequence.