Growth acceleration results in faster telomere shortening later in life

There is a wealth of evidence for a lifespan penalty when environmental conditions influence an individual´s growth trajectory such that growth rate is accelerated to attain a target size within a limited time period. Given this empirically demonstrated relationship between accelerated growth and lifespan, and the links between lifespan and telomere dynamics, increased telomere loss could underpin this growth-lifespan trade. We experimentally modified the growth trajectory of nestling zebra finches (Taeniopygia guttata), inducing a group of nestlings to accelerate their growth between 7 and 15 days of age, the main phase of body growth. We then sequentially measured their telomere length in red blood cells at various time points from 7 days to full adulthood (120 days). Accelerated growth between 7 and 15 days was not associated with a detectable increase in telomere shortening during this period compared with controls. However, only in the treatment group induced to show growth acceler...