Dog Genetics Introduction

DNA sequencing is a helpful tool in determining the exact nucleotide sequence of a particular genome. The Sanger Method is a particular way this can be achieved. This method feeds off of DNA replication occurring naturally within a cell. The DNA needs a primer to begin the process but can be stopped with the addition of a dideoxynucleotide. The reason the process is stopped when a dideoxynucleotide is added is due to the missing OH group on the 3’ end. Therefore, a fragment of DNA can be sequenced with a large amount of the DNA sequence of interest, a large amount of primers, DNA polymerase, an excess of nucleotides, and a small amount of one of the dideoxynucleotides. Due to the ratio of high normal, deoxynucleotide, to low dideoxynucleotides, there will be termination of the sequence at many different places. This process can also be done with all of the nucleotides labeled with different florescent dyes. If the fragments were then run on a gel, the piece of DNA could be sequenced. The use of capillaries is a technological way of doing this (J. Laney, Sequencing Slides. Moodle.1, 1-17 (2018)).