Search for Novel SNPs in XPC, XPD and XPG genes

Abstract

SNP (Single nucleotide polymorphism) is one of the most common types of genetic variations in the DNA sequence. There are many causes of SNPs. DNA methylation is one of the significant causes of SNPs. DNA methylation is an epigenetic mechanism that involved in number of events viz. gene regulation, gene imprinting, and X chromosome inactivation and even in diseases like cancer. It has been found that the pattern of variation or alteration in DNA methylation of cytosine residue is one of the consistent molecular changes in human tumors or cancer. DNA methylation is mainly occurs at cytosine residue in CG containing sites in mammalian genome. CG sites act as mutational hotspot viz. CG/CG  TG/CA which is a phenomenon in vertebrate genome due to DNA methylation. In order to search for novel SNPs in the DNA repair genes, we have used RFLP analysis by using the tetra-nucleotide site (CCGG) of HapII restriction enzyme. This study identified one putative SNP in the region of XPD gene and also shows that there is potential role of association of CG dinucleotides with the genetic polymorphism in the genome.