Abstract
ABSTRACTThere is increasing evidence from endothermic vertebrates that telomeres, which cap the ends of chromosomes and play an important role in chromosome protection, decline in length during postnatal life and are a useful indicator of physiological state and expected lifespan. However, much less is currently known about telomere dynamics in ectothermic vertebrates, which are likely to differ from that of endotherms, at least in part due to the sensitivity of ectotherm physiology to environmental temperature. We report here on an experiment in which Atlantic salmon (Salmo salar) were reared through the embryonic and larval stages of development, and under differing temperatures, in order to examine the effects of environmental temperature during early life on telomere dynamics, oxidative DNA damage and cellular proliferation. Telomere length significantly increased between the embryonic and larval stages of development. Contrary to our expectations, variation in telomere length at the end of the larval stage was unrelated to either cell proliferation rate or the relative level of oxidative DNA damage, and did not vary between the temperature treatments. This study suggests that salmon are able to restore the length of their telomeres during early development, which may possibly help to buffer potentially harmful environmental effects experienced in early life.
Highlights
Conditions experienced in early life can have permanent effects on individual phenotypes (Lindström, 1999; Monaghan, 2008)
A potential mechanistic link between early life conditions and later life viability lies in the telomeres, which cap the ends of eukaryotic chromosomes and play an important role in chromosome protection
We examined two potential mechanistic pathways that may link temperature and telomere length, with the predictions that: (A) there would be a positive relationship between incubation temperature and levels of oxidative damage, and (B) there would be a negative relationship between incubation temperature and cell proliferation rate, with a relative shift from cell division to cell growth at relatively warmer temperatures
Summary
Conditions experienced in early life can have permanent effects on individual phenotypes (Lindström, 1999; Monaghan, 2008). It is possible that individual ectotherms that differ in developmental rate (but are of the same age) will differ in telomere length, since developmental rate could be linked to rates of cell division and, potentially, levels of oxidative damage. Embryos developing in relatively warmer water appear to be achieving growth by disproportionately increasing the size of their existing cells (hypertrophy), which might result in having longer telomeres for a given body size than conspecifics developing in colder water In this experiment, we examined telomere length at two early life stages (embryo and larva) in Atlantic salmon (Salmo salar Linnaeus 1758), and whether this was influenced by differences in environmental temperature. We examined two potential mechanistic pathways (levels of oxidative DNA damage and rates of cell proliferation) that may link temperature and telomere length, with the predictions that: (A) there would be a positive relationship between incubation temperature and levels of oxidative damage, and (B) there would be a negative relationship between incubation temperature and cell proliferation rate, with a relative shift from cell division to cell growth at relatively warmer temperatures
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call