Lesson 3: DNA's Role in Determining Your Traits
A typical human gene has about 1000 base pairs that code for one protein. On average, we expect that one of the base pairs in any gene would vary in at least 1% of people. This kind of variation is called a single nucleotide polymorphism or SNP for short.
"Poly" means many and "morphism" means form. A polymorphic DNA sequence is a sequence that has more than one form in different people. A SNP is a location along a genomic sequence that varies from person to person. SNPs are responsible for many of the different traits we observe among people. You inherit your SNPs from your parents. Everyone has thousands of SNPs, but they are not found in all genes.
