Gene Mutation of Longevity

Julia Huynh

ID: S4291797

The process of aging has always been a mysterious concept when you consider how the lifespan of different organisms differ so greatly. It is questionable as to why some organisms such as the owl, has a lifespan of about eight years, in comparison to the parrot which can live up to thirty years. This has led scientists to investigate further into this particular concept to discover on a genetic level, how longevity is affected. Genes are distinctly responsible for inheritance and can be expressed as a phenotype. It codes for polypeptides which controls a precise regulated process in gene expression (Reece et al, 2012). Greer and his team of scientists, conducted research on small worms called Caenorhabditis elegans and made a discovery as to how DNA can be altered to affect the lifespan of the organism. The COMPASS complex was found to play one of the main roles in the aging process. Therefore by changing the role of the protein, the key pathway to modulating the aging process is ultimately affected to result in a generation of longer living organisms. Mutating this protein causes disruptions in histone regulation, leading to a longer lifespan in Caenorhabditis elegans (MANGO, 2011). This can be considered as mutagenic activity which can be transmitted across to offspring (Reece et al, 2012). Their research demonstrated that several future generations of C. elgans do indeed have a significantly longer lifespan than their ancestors. This is significant because it shows that not only has the phenotype for the expression of the gene are able to be observed, but also that it was a genetically inheritable trait (MANGO, 2011).

Although this seems to be the case, by the fifth generation of crossing a COMPASS mutant worm with a normal worm, the trait of a longer lifespan of C. Elgans had been reversed. This was considered to be the transgenerational effects of COMPASS mutations on longevity. This is shown in the following diagram:

Figure 1 COMPASS mutations on longevity and transgenerational effects (Nature Publishing Group, 2011)

This shows that the presence of functional germ cells were necessary for the genetic material to be passed on. It also suggests that there were multi-generational consequences involved in the process resulting in gene silencing. The modification of the histone undergoes methylation in a particular amino acid resulting in H3K4me modification. It is suggested that both COMPASS mutants and H3K4me activates gene expressions therefore by lacking H3K4me, can correlate to a shorter lifespan, hence why at the fifth generation, the genetic material was returned to what the organism initially had. (MANGO, 2011) Through this newly discovered research, it has been discovered that there is a specific gene in C. elegans which codes for protein controlling the aging process in the organism. This research is the foundation of future research into the function of the COMPASS Complex in other organisms and can also lead to further research in genes being responsible for longevity. For more information regarding this topic, visit http://www.nature.com.ezproxy.library.uq.edu.au/nature/journal/v479/n7373/full/479302a.html#/references

Bibliography

MANGO, S. E. (2011). Generations of longevity. Macmillan Publishers Limited, 479, 302-303.

http://www.nature.com.ezproxy.library.uq.edu.au/nature/journal/v479/n7373/pdf/479302a.pdf

- Anway, M. D., Cupp, A. S., Uzumcu, M. & Skinner, M. K. Science 308, 1466–1469 (2005).

- Bygren, L. O., Kaati, G. & Edvinsson, S. Acta Biotheor. 49, 53–59 (2001).

- Greer, E. L. et al. Nature 466, 383–387 (2010).

- Greer, E. L. Nature 479, 365–371 (2011).

- Kenyon, C. J. Nature 464, 504–512 (2010).

- Li, T. & Kelly, W. G. PLoS Genet. 7, e1001349 (2011)

- Ng, S.-F. et al. Nature 467, 963–966 (2010).

- Pferdehirt, R. R., Kruesi W. S. & Meyer, B. J. Genes Dev. 25, 499–515 (2011).

- Wang, M. C., O'Rourke, E. J. & Ruvkun, G. Science 322, 957–960 (2008).

-Daxinger, L. & Whitelaw, E. Genome Res. 20, 1623–1628 (2010).

Nature Publishing Group. (2011, November 16). Ageing: Generations of longevity. Retrieved March 19, 2012, from Nature - International weekly journal of science: http://www.nature.com.ezproxy.library.uq.edu.au/nature/journal/v479/n7373/full/479302a.html#/references

Reece et al, J. (2012). Campbell Biology. In M. U. Reece, Campbell Biology (9th ed., pp. 350-353). Australia: Pearson Australia Group Pty Ltd.