Mutations and Polymorphisms: What Is The Difference?

The human genome exhibits a dynamic but limited variation between different individuals and across different geographical and/or racial/ethnical populations which accounts for only 0.1–0.4% of the total genomic DNA or genome. These genetic variations are generally described in terms of mutation and genetic polymorphism. Mutation is defined as the irreversible sequence variation in the DNA which essentiality encompasses all types of variations occurring in the human genome spontaneously or non-spontaneously. Genetic polymorphism which is the most common and dynamic form of genetic variation present throughout the human genome is defined as the presence of two or more alternative forms of an allele in the genome of any individual, which results in distinct phenotypes in the same population. Genetic polymorphism represents most of the variations present in the human genome and includes four different annotated types, viz. single nucleotide polymorphisms (SNPs), copy number variants (CNVs), insertions or deletions (indels), and structural variants. Of these, single nucleotide polymorphisms (SNPs), which involve the substitution of a single nucleotide by another nucleotide at a specific location within the genome, account for more than 90% of all the human genetic variations and thus constitute an important aspect of genetic variation exhibited by the human genome.