In: Biology
Single Nucleotide Polymorphisms are the most common type of variations caused in our DNA at the foundational level .i.e at the nucleotide level. For instance, due to the action of an SNP, Guanine(G) could be substituted by Cystine(C) in the nucleotide sequence; AACGAT, which would result in the sequence AACCAT. These simple changes could be of transversion or transition type and occur almost once every 1000 nucleotides which means that there are approximately 4 to 5 million SNPs in a person's genome. These SNPs can cause either a non-synnymous or a synonymous mutation depending on the area of varaiton.
Since, the frequency of SNPs occuring in our Genome is very high and the position at which they take place could result in different outcomes, all SNPs in an organism are not subject to phenotypic changes.