Telomeres, Telomerase, Stress, and Aging

Why should a behavioral scientist study telomeres? Mainte nance of telomeres, the natural ends of linear chromosomes, is a fundamental biological mechanism of all eukaryotic cells, from protozoa to humans. Gradual shortening of telomeres after each cell division eventually can lead to loss of cellular division capacity and cell death, and contribute to genomic instability, a characteristic of cancer. Telomeres and telomerase, the enzyme that adds nucleotides to telomere ends, have been linked to human aging and aging related diseases (Aubert & Lansdorp, 2008). Further, lifestyle and psychological state are increasingly being associated with telomere length and telom erase activity changes. Thus, telomere length and telomerase activity emerge as new biomarkers for cellular aging and may serve as surrogate markers for factors that contribute to aging and aging related diseases. Therefore, scientists interested in understanding early onset of aging related diseases, as well as longevity, may want to include this measure of cell aging. This chapter gives the behavioral scientist a general understanding of the telomere/telomerase maintenance system, from its molecular basis, to clinical observations, to measurement. It addresses such questions as: Why do telomeres shorten? What are the consequences of telomere shortening? How are telomeres and telomerase related to cancer and diseases of aging? And, lastly and most relevant to behavioral scientists, what environmental (nongenetic) factors modulate telomere length? For detailed discussion of each topic, readers are encouraged to read the literature cited in this chapter.