Genetic+polymorphism

=Genetic polymorphism=

A **genetic polymorphism ** is the existence of two or more variants - which may be allelic, phenotypic, chromosomal or general DNA sequence variants - at significant frequencies in a population. A frequency of 1% or more is generally considered to be a polymorphism.

Types of polymorphism include:

 Genetic polymorphisms can be useful as genetic markers, allowing us to home in on the genetic locus for certain inherited diseases.
 * **Single nucleotide polymorphisms (SNPs) ** where there is a change in one nucleotide. These are very common in the human genome, with a single-nucleotide sequence variant occurring roughly once every 100-300bp, on average
 * **Restriction fragment length polymorphisms (RFLPs, or 'rif-lips') ** is variation in the length of a fragment produced on digestion with restriction enzymes. This is due to mutations which move the restriction site about