What is the Difference Between dNTP and DdNTP?

The main difference between dNTP and ddNTP lies in their structure and function in DNA synthesis:

• dNTPs are deoxyribonucleotide triphosphates, which are building blocks of DNA. They contain a 3'OH group in the deoxyribose sugar, allowing them to form phosphodiester bonds and lengthen the DNA sequence.
• ddNTPs are dideoxynucleotide triphosphates, which are nucleotides used in the Sanger sequencing method. They do not contain a 3'OH group in the deoxyribose sugar, preventing them from forming phosphodiester bonds and terminating the DNA sequence.

In the Sanger sequencing method, a mixture of dNTPs and ddNTPs is added along with DNA primers and polymerases. As the DNA chain starts to lengthen, a ddNTP is randomly incorporated into the chain, and because it lacks a 3'OH group, no phosphodiester bond can be formed for the addition of the next nucleotide, resulting in the termination of the chain. The ddNTPs are fluorescently labeled for easy detection during the sequencing process.

Comparative Table: dNTP vs DdNTP

Here is a table comparing the differences between dNTP and ddNTP:

dNTPs (deoxyribonucleotides) are the building blocks of DNA and contain a 3'OH group in their deoxyribose sugar. They are used to synthesize DNA. In contrast, ddNTPs (dideoxynucleotides) lack a 3'OH group in their deoxyribose sugar and are used in the Sanger sequencing method to terminate DNA synthesis at different lengths.