throughout the cycle, the inverted region will be repeated leading to an increase in copy number. The last mechanism that can lead to copy number variations is polymerase slippage, which is also known as template switching. During normal DNA replication, the polymerase on the lagging strand is required to unclamp and re-clamp the replication region continuously. When small scale repeats in the DNA sequence exist already, the polymerase can be 'confused' when it re-clamps to continue replication and instead of clamping to the correct base pairs, it may shift a few base pairs and replicate a portion of the repeated region again. Note that although this has been experimentally observed and is a widely accepted mechanism, the molecular interactions that led to this error remains unknown. In addition, because this type of mechanism requires the polymerase to jump around the DNA strand and it is unlikely that the polymerase can re-clamp at another locus some kilobases apart, therefore this is more applicable to short repeats such as dinucleotide or trinucleotide repeats. Alpha-amylase gene Amylase is an enzyme in saliva that is responsible for the breakdown of starch into monosaccharides, and one type of amylase is encoded by the alpha-amylase gene (AMY1). The AMY1 locus, as well as the amylase enzyme, is one of the most extensively studied and sequenced gene in the human genome. Its homologs are also found in other primates and therefore it is likely that the primate AMY1 gene is ancestral to the human AMY1 gene and was adapted early in primate evolution. AMY1 is one of the most well studied genes which has wide range of variable numbers of copies throughout different human populations. The AMY1 gene is also one of the few genes that had been studied that displayed convincing evidence which correlates its protein function to its copy number. Copy number is known to alter transcription as well as translation levels of a particular gene, however research has shown that the relationship between protein levels and copy number is variable. In the AMY1 genes of European Americans it is found that the concentration of salivary amylase is closely correlated to the copy number of the AMY1 gene. As a result, it was hypothesized that the copy number of the AMY1 gene is closely correlated with its protein function, which is to digest starch. The AMY1 gene copy number has been found to be correlated