In a study published today (March 21) in PLOS ONE, a different group of researchers from the French National Center for Scientific Research in Villiers en Bois, France, report seemingly contradictory findings: young birds, they find, produce chicks with shorter telomeres and poorer body conditions compared to middle-aged birds. Rather than using an experimental approach, Frederic Angelier and his colleagues took samples from black-browed albatrosses (Thalassarche melanophrys) in the wild.
A striking difference between the two studies is the lifespans of the bird species, which fall on the extreme ends of the longevity spectrum of birds, writes Angelier in an email to The Scientist. Zebra finches (Species name) live between five and eight years years, while the albatrosses live upwards of 40 years. Longevity can have an effect on reproductive strategies, he adds.
Another distinction is that Jose Noguera of the University of Vigo in Spain and his colleagues used an experimental system. They mated zebra finches in the lab and measured telomere lengths of the resulting embryos, not birds that developed to term, to address how paternal age effects offspring telomere length. This set-up removed any post-hatching environmental factors, including their parents’ care, that might influence telomere length. “The story could be slightly different in populations [of zebra finches] that have to face several environmental constraints in the wild,” writes Angelier.
In contrast, Angelier tested whether, in a wild population, middle-aged albatross parents with more experience in rearing young would have healthier offspring with longer telomeres at three months of age compared to those of young, inexperienced parents. In comparing the two reports, Angelier is now wondering whether sampling the telomere lengths of offspring fathered by very old albatross parents would result in similar shorter telomere lengths that Noguera found in his work.
For both Noguera and Angelier, the two studies are complementary. “We need more experimental studies on different species to understand how parental age influences offspring telomere lengths and whether the patterns are species-specific or not,” writes Noguera in an email to The Scientist.
S.M. Dupont et al., “Young parents produce offspring with short telomeres: A study in a long-lived bird, the Black-browed Albatross (Thalassarche melanophrys),” PLoS ONE, 13:e019352, 2018.
J.C. Noguera et al., “Experimental demonstration that offspring fathered by old males have shorter telomeres and reduced lifespans,” Proc R Soc B, doi:10.1098/rspb.2018.0268, 2018.