The most common type of genetic variation is called a Single Nucleotide Polymorphism (SNP).
A SNP is defined as a single base change in a DNA sequence that occurs in a significant proportion (more than 1 percent) of a large population. The single base is replaced by any of the other three bases. Here is an example: in the DNA sequence TAGC, a SNP occurs when the G base changes to a C, and the sequence becomes TACC.
![SNPS Are the Most Common Type of Variation](https://webarchive.library.unt.edu/eot2008/20090117095611im_/http://www.cancer.gov/images/Documents/f6e06278-e717-4465-b5b4-fda72f95584b/cancer13.jpg)
< Previous | Index | Next Slide > |