User:Mtur/Pseudogene

Pseudogenes are genes present in an organism's genome that have lost the ability to code for proteins due to mutation. Pseudogenes are often difficult to parse from the large amount of non-coding base pairs in the genome. Convention requires to two elements to be present to label a sequence a pseudogene. The first is homology which is the requirement that a sequence be demonstrated to descend from a functional copy of the gene and the second is non-functionality which is the requirement that the gene not code for a protein in the organism in question.

Since all pseudogenes are descended from a functioning gene the first step is to find a species that has a functioning copy of that gene. This is done by looking at phylogenetic trees and testing organisms with a relatively recent common ancestor and working backwards until a copy is found. Once a functioning copy of a gene is detected its sequence is compared to the pseudogene. A high correlation in base pairs is used to assign homology. Non-functionality can be demonstrated by attempting to transcribe the sequence in-vitro. Humans have many pseudogenes including L-gulonolactone oxidase which is used to synthesize vitamin c. This gene was inactivated in the common ancestor of all simians.

See also

Endogenous retrovirus

L-gulonolactone oxidase

References

• Vanin, E. F. (1985). "Processed pseudogenes: characteristics and evolution." Annu Rev Genet 19: 253-72.