Genome refers to the collection of all genes of an organism. The human genome contains 2.9 billion base pairs and approximately 20,000 – 25,000 protein-coding genes.
Genome instability refers to a high frequency of mutations within a species' genome. Cancer occurs from cumulative mutations of genes that promote cell proliferation, apoptosis, and migration as well as genes that function to suppress tumors and/or repair DNA damage.
It is thought that in cancer there are an average 60-70 mutated genes. Of course, only a small handful are the "driver" genes, whereas the rest are "passenger" genes which may not be pathogenic. Among the many challenges in studying cancer is how one can distinguish between "driver" and "passenger" genes. Understanding these differences should allow for the development of new treatment strategies for cancers.
Single nucleotide polymorphisms (SNPs)
There are four building blocks of DNA designated as: Adenine (A), Thymine (T), Guanine (G), and Cytosine (C). These building blocks are called nucleotides. Molecular rules of complimentary pairing of A-T and G-C must be followed to maintain DNA fidelity.
A single nucleotide polymorphism (SNP) takes place when a nucleotide normally found at a specific locus on a gene segment is replaced by a different nucleotide. SNP is a type of DNA variation among individuals and marks individual differences. Depending on the location and genes affected, SNPs can interact with environmental factors that collectively drive tumorigenesis.
