What Can We Learn from Pseudogenes? Essay examples -- Biology

After many extensive molecular investigations of gene families, it has become apparent that a large majority of genes have multiple copies of themselves. This seemingly unnecessary amount of duplicates has led to further research, revealing that these ‘extra’ genes cannot successfully code for proteins (Proudfoot, 1980). These genes were therefore labeled as functionless sequences of DNA, and aptly named pseudogenes. This discovery poses many questions regarding the role and origin of these supposedly non-functional genes, but most importantly what else can we learn from them? Unfortunately, DNA that cannot be expressed into proteins is useless in regards to investigations of the molecular clock (Martin, 1990), however further research proves that we can learn a lot from pseudogenes. In order to explore what we can learn from pseudogenes, we need to understand them. Firstly, there are two main types of pseudogene, processed and unprocessed. Processed pseudogenes, also known as retropseudogenes, are sequences of transposable DNA that have been reverse transcribed back from mRNA, but have somehow failed to replicate crucial protein coding elements when assimilated back into the genome (Graur and Li, 2000: Skalka and Goff, 1993). Unprocessed pseudogenes can occur by simple replication of a pre-existing pseudogene, or due to adverse point mutations in ‘normal’ functioning genes that can trigger a frame shift in the original protein code. This frame shift can for example, lead to a mixture of premature stop codons and elimination of splicing sites, rendering the gene faulty (Li, Graur and Shuali, 1989). Initially it was believed that pseudogenes have no purpose, just selfish, parasitic DNA clogging up the genome (Orgel, Crick and ... ...e4573de165161150&searchtype=a> [Accessed 12th November 2010] (20) Nishikimi, M. et al. 1994. Cloning and Chromosmal Mapping of the Human Nonfunctional Gene for L-Guluno-y-Lactone Oxidase, the Enzyme for L-Absorbic Acid Biosynthesis Missing in Man*, The Journal of Biological Chemistry, [online] Available at: [Accessed 12th November 2010] (21) Sakai, H. Itoh, T. Gojobori, T. 2008. Processed Pseudogenes and Their Functional Resurrection in the Human and Mouse Genomes, Wiley: Online Library, [online] Available at: http://onlinelibrary.wiley.com/doi/10.1002/9780470015902.a0021000/abstract> [Accessed 12th November 2010] Websites (19) The True.Origin Archive: Exposing the Myth of Evolution.2010. Pseudogenes: Are They Non-Functional? [online] Available at: [Accessed 9th November 2010]