Telomere dynamics in the first year of life, but not later in life, predict lifespan in a wild bird

Telomeres are protective, nucleoprotein structures at the end of chromosomes that have been associated with lifespan across taxa. However, the extent to which these associations can be attributed to absolute length versus the rate of telomere shortening prior to sampling remains unresolved. In a longitudinal study, we examined the relationship between lifespan, telomere length and the rate of telomere shortening in wild, purple-crowned fairy-wrens (Malurus coronatus coronatus). To this end, we measured telomere length using qPCR in the blood of 59 individuals sampled as nestling and 4-14 months thereafter, and in 150 individuals sampled on average three times across adulthood. We applied within-subject centering analyses to simultaneously test for associations between lifespan and average telomere length and telomere shortening. We reveal that the rate of telomere shortening in the first year of life predicted lifespan, with individuals with faster shortening rates living less long. We also report a trend for an effect of telomere length in the first year of life on lifespan, independent of telomere shortening. In contrast, in adulthood neither telomere shortening, nor telomere length predicted lifespan, despite a considerably larger data set. Our results suggest that telomere length measured very early in life (during development) and longitudinal assessments of telomere shortening during the first year of life constitute more useful biomarkers of total life expectancy than either telomere length measured after development, or telomere shortening later in adulthood.

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The Development of Swallowing Respiratory Coordination

Perspectives on Swallowing and Swallowing Disorders (Dysphagia) ◽

10.1044/sasd18.1.19 ◽

2009 ◽

Vol 18 (1) ◽

pp. 19-24

Author(s):

Maggie-Lee Huckabee

Keyword(s):

Cortical Activation ◽

First Year ◽

Healthy Children ◽

Nasal Airflow ◽

Single Session ◽

Primary Finding ◽

Patterns Of Behavior ◽

Cortical Modulation ◽

First Year Of Life ◽

Swallowing Apnea

Abstract Research exists that evaluates the mechanics of swallowing respiratory coordination in healthy children and adults as well and individuals with swallowing impairment. The research program summarized in this article represents a systematic examination of swallowing respiratory coordination across the lifespan as a means of behaviorally investigating mechanisms of cortical modulation. Using time-locked recordings of submental surface electromyography, nasal airflow, and thyroid acoustics, three conditions of swallowing were evaluated in 20 adults in a single session and 10 infants in 10 sessions across the first year of life. The three swallowing conditions were selected to represent a continuum of volitional through nonvolitional swallowing control on the basis of a decreasing level of cortical activation. Our primary finding is that, across the lifespan, brainstem control strongly dictates the duration of swallowing apnea and is heavily involved in organizing the integration of swallowing and respiration, even in very early infancy. However, there is evidence that cortical modulation increases across the first 12 months of life to approximate more adult-like patterns of behavior. This modulation influences primarily conditions of volitional swallowing; sleep and naïve swallows appear to not be easily adapted by cortical regulation. Thus, it is attention, not arousal that engages cortical mechanisms.

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