Single Nucleotide Polymorphisms: A Deep Consideration of Protein Sequence Variation

Introduction: Human genome consists of the three billion base pairs that has about one percent of genetic variation from one person to another، which determines physical، psychological، and susceptibility to diseases. Among the types of genetic diversity, single nucleotide polymorphisms are one of the most important genetic differences between two people. Single nucleotide polymorphism variation is located in the promoter region, exons، introns، untranslated regions and other Deoxyribonucleic acid (DNA) regions. While variation in the exon region can change susceptibility to diseases depending on whether it changes the protein structure or affects translation kinetics. Diversity in the promoter region can affect the interaction of genetic and epigenetic elements. Also، variation in the promoter region can affect the DNA methylation status. Polymorphic variation in the intron region can affect Messenger Ribonucleic acid splicing and the function of cis-regulatory elements. Polymorphic variation in the 5' Untranslated region، region causes a change in translation efficiency,، while a change in the 3' Untranslated region binds micro Ribonucleic acids to their position then affects the effects. In some cases، variations in Transfer Ribonucleic acid (tRNA) and Ribosomal ribonucleic acid (rRNA) affect the function of these regulatory cis elements. Conclusion: From a clinical point of view, a deep knowledge of this type of genetic variation can help the treatment process, manage patients and understand the prognosis based on these SNPs. Private or personalized medicine is also fundamentally based on genetic diversity. In this article, it was reviewed the types of single nucleotide genetic variation and presented examples of types of cancer, neurological and immunological diseases.