RAPID SENESCENCE IN SOCKEYE SALMON

INSIGHTS FROM TELOMERES

Caroline StorerTom Quinn Steven Roberts

Alaska Salmon Program Symposium 2010

Senescence in sockeye salmon

• Adaptive variation of senescence within populations

• Significant variation in in-stream longevity (i.e., rate of senescence) among populations

• Links to other aspects of fitness such as energetic investment in gonads versus body stores (Hendry et al.

2004)

WHAT PHYSIOLOGICAL PROCESSES REGULATE

SENESCENCE IN SOCKEYE SALMON?

Study site

Previous research (2008-2009)

• Baseline information on physiological changes between “arriving” and senescent salmon

• Cortisol signaling declines during senescence

• Molecular chaperone protein (HSP) is up-regulated during senescence

• Molecules controlling “other” primary process are differentially expressed (immune, reproduction, olfaction, and memory)

New approach

Examine new physiological process:

New approach

Examine new physiological process:Telomere shortening

Why telomeres?

Why telomeres?

• Telomeres shorten in length with age

• Telomere shortening is significantly correlated with decline in physiological health (Terry et al. 2008)

• Telomere length can be inherited (Atzmon et al. 2010)

• Critical telomere length could be one possible trigger of senescence (Armanios 2009)

New question

Does telomere shortening directly trigger senescence and/or regulate rate of senescence in

sockeye salmon?

Samples (2010)

• Fin clips and tagging of arriving fish

• Early and late arriving fish

• Fin clips of tagged fish at multiple “in-stream” time points (i.e. day 2, day 6)

• http://goo.gl/tCeJ7

New methods

• High-throughput PCR based fluorescent assay for the normalized measurements of relative telomere length

New methods

• High-throughput PCR based fluorescent assay for the normalized measurements of relative telomere length

Log Telomere Length

Fluore

scence

Preliminary results

Juvenile Adult0

10

20

30

40

50

60M

ean

Rela

tive T

elo

mere

Len

gth

Summary and next steps

• We can measure telomere length

• However, assay needs to be optimized for greater sensitivity

Summary and next steps

• We can measure telomere length

• However, assay needs to be optimized for greater sensitivity

• Is there a difference in telomere length between early (slow senescing) and late (fast senescing) arriving fish?

• Does telomere length shorten during rapid senescence?

Implications

• Provides insight into the evolution of life history strategies and phenotypic variation in longevity

• Rapid senescence in sockeye salmon could be used a model to study aging and longevity in other organisms

Acknowledgments

• The 2010 sampling crew, especially Curry Cunningham, Jackie Carter, Brian Quinn, and Wes Larson

• Leslie Jensen

• The Alaska Salmon Program

• Roberts Lab

• Seeb Lab