Biological aspects of of human ageing
Bittles, A.H. (2008) Biological aspects of of human ageing. In: Jacoby, R., Oppenheimer, C., Dening, T. and Thomas, A., (eds.) Oxford Textbook of Old Age Psychiatry. Oxford University Press, Oxford, pp. 3-15.
The overall goal of this chapter is to review present knowledge of the biological processes that govern human ageing. Almost inevitably, during the last decade the Human Genome Project has had a strong impact on research into the biological aspects of ageing, DNA analysis now offering major insights into changes in gene expression with advancing age. Nonetheless, a key consideration that still needs to be addressed is the nature of the relationship between ageing and evolution, and whether ageing should be considered as an adaptive or a non-adaptive trait. In other words, did senescence evolve as a direct result of natural selection in order to limit lifespan, or did increases in longevity follow random events which ordinarily would be expected to restrict that lifespan? Although adaptive theories have their attractions, it is non-adaptive hypotheses which primarily regard senescence as an evolutionary by-product that are now favoured (Kirkwood, 2002).
A second basic issue concerns the onset of ageing and, more specifically, its timing. Is ageing in mammals and other genera part of an overall developmental process commencing at conception or birth, or can a specific switch be observed later in life? To a large extent this question echoes the adaptive/non-adaptive conundrum, and although convincing evidence is available for significant changes in gene expression with advancing age, the concept of specific ageing genes and their activation in adulthood appears improbable (Partridge and Gems, 2002).
|Publication Type:||Book Chapter|
|Murdoch Affiliation:||Centre for Comparative Genomics|
|Publisher:||Oxford University Press|
|Copyright:||© Oxford University Press 2008|
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