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1. Parental age does not influence offspring telomeres during early life in common gulls (Larus canus)

   https://doi.org/DOI: 10.1111/mec.15905  

   Sepp, T. ; Meitern, R ; Heidinger, B. ; Noreikiene, K. ; Rattiste, K. ; Horak, P. ; Saks, L. ; Kittilson, J. ; Urvik, J. ; Giraudeau, M. ( January 2021 , Molecular ecology)

   null (Ed.)

   Parental age can affect offspring telomere length through heritable and epigenetic-like effects, but at what stage during development these effects are established is not well known. To address this, we conducted a cross-fostering experiment in common gulls (Larus canus) that enabled us distinguish between pre-and post-natal parental age effects on offspring telomere length. Whole clutches were exchanged after clutch completion within and between parental age classes (young and old) and blood samples were collected from chicks at hatching and during the fastest growth phase (11 days later) to measure telomeres. Neither the ages of the natal nor the foster parents predicted the telomere length or the change in telomere lengths of their chicks. Telomere length (TL) was repeatable within chicks, but increased across development (repeatability = 0.55, intraclass correlation coefficient within sampling events 0.934). Telomere length and the change in telomere length were not predicted by post-natal growth rate. Taken together, these findings suggest that in common gulls, telomere length during early life is not influenced by parental age or growth rate, which may indicate that protective mechanisms buffer telomeres from external conditions during development in this relatively long-lived species. 

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2. Testing for paternal influences on offspring telomere length in a human cohort in the Philippines

   https://doi.org/10.1002/ajpa.23983  

   Eisenberg, Dan T. A. ; Rej, Peter H. ; Duazo, Paulita ; Carba, Delia ; Hayes, M. Geoffrey ; Kuzawa, Christopher W. ( December 2019 , American Journal of Physical Anthropology)

   Telomeres, emerging biomarkers of aging, are comprised of DNA repeats located at chromosomal ends that shorten with cellular replication and age in most human tissues. In contrast, spermatocyte telomeres lengthen with age. These changes in telomere length (TL) appear to be heritable, as older paternal ages of conception (PAC) predict longer offspring TL. Mouse‐model studies raise questions about the potential for effects of paternal experiences on human offspring TL, as they suggest that smoking, inflammation, DNA damage, and stressors all shorten sperm TL. Here, we examined whether factors from the paternal environment predict offspring TL as well as interact with PAC to predict offspring TL.

   Using data from the Philippines, we tested if smoking, psychosocial stressors, or shorter knee height (a measure of early life adversity) predict shorter offspring TL. We also tested if these interacted with PAC in predicting offspring TL.

   While we did not find the predicted associations, we observed a trend toward fathers with shorter knee height having offspring with longer TL. In addition, we found that knee height interacted with PAC to predict offspring TL. Specifically, fathers with shorter knee heights showed a stronger positive effect of PAC on offspring TL.

   While the reasons for these associations remain uncertain, shorter knee height is characteristic of earlier puberty. Since spermatocyte TL increases with the production of sperm, we speculate that individuals with earlier puberty, and its concomitant commencement of production of sperm, had more time to accumulate longer sperm telomeres.

    

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3. TA‐65 does not increase telomere length during post‐natal development in house sparrow chicks ( Passer domesticus )

   https://doi.org/10.1002/jez.2449  

   Vangorder‐Braid, Jennifer T. ; Sirman, Aubrey E. ; Kucera, Aurelia C. ; Kittilson, Jeffrey D. ; Kibble, Tania M. ; Heidinger, Britt J. ( March 2021 , Journal of Experimental Zoology Part A: Ecological and Integrative Physiology)

   Telomeres, protective caps at the end of chromosomes, are often positively related to lifespan and are thought to be an important mechanism of organismal aging. To better understand the casual relationships between telomere length and longevity, it is essential to be able to experimentally manipulate telomere dynamics (length and loss rate). Previous studies suggest that exposure to TA‐65, an extract from the Chinese rootAstragalus membranaceus, activates telomerase, lengthens telomeres, increases the growth of keratin‐based structures, and boosts the immune system in adults. However, telomere loss is expected to be greatest during early life but whether TA‐65 has similar effects during this life stage is currently unknown. Here, we experimentally exposed free‐living house sparrow (Passer domesticus) chicks to TA‐65 during post‐natal development and examined the effects on telomere length and loss, growth of keratin‐based structures, and a measure of cellular immunity. Contrary to expectation, the growth of keratin‐based structures was reduced in TA‐65 chicks and in the second year of the study, chicks exposed to TA‐65 experienced more telomere loss than controls. Thus, the effects of TA‐65 on telomeres and keratin‐based structures differ across life stages and future research will be necessary to determine the mechanisms underlying these age‐specific effects.

    

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4. Transmissible cancer and longitudinal telomere dynamics in Tasmanian devils ( Sarcophilus harrisii )

   https://doi.org/10.1111/mec.16721  

   Madsen, Thomas ; Klaassen, Marcel ; Raven, Nynke ; Dujon, Antoine M. ; Jennings, Geordie ; Thomas, Frédéric ; Hamede, Rodrigo ; Ujvari, Beata ( October 2022 , Molecular Ecology)

   A plethora of intrinsic and environmental factors have been shown to influence the length of telomeres, the protector of chromosome ends. Despite the growing interest in infection–telomere interactions, there is very limited knowledge on how transmissible cancers influence telomere maintenance. An emblematic example of transmissible cancer occurs in the Tasmanian devil (Sarcophilus harrisii), whose populations have been dramatically reduced by infectious cancer cells. To investigate associations between telomere dynamics and the transmissible cancer, we used longitudinal data from a Tasmanian devil population that has been exposed to the disease for over 15 years. We detected substantial temporal variation in individual telomere length (TL), and a positive significant association between TL and age, as well as a marginally significant trend for devils with devil facial tumour disease (DFTD) having longer telomeres. A proportional hazard analysis yielded no significant effect of TL on the development of DFTD. Like previous studies, we show the complexity that TL dynamics may exhibit across the lifetime of organisms. Our work highlights the importance of long‐term longitudinal sampling for understanding the effects of wildlife diseases on TL.

    

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5. The telomere regulatory gene POT1 responds to stress and predicts performance in nature: Implications for telomeres and life history evolution

   https://doi.org/10.1111/mec.16237  

   Wolf, Sarah E. ; Sanders, Tiana L. ; Beltran, Sol E. ; Rosvall, Kimberly A. ( November 2021 , Molecular Ecology)

   Telomeres are emerging as correlates of fitness‐related traits and may be important mediators of ecologically relevant variation in life history strategies. Growing evidence suggests that telomere dynamics can be more predictive of performance than length itself, but very little work considers how telomere regulatory mechanisms respond to environmental challenges or influence performance in nature. Here, we combine observational and experimental data sets from free‐living tree swallows (Tachycineta bicolor) to assess how performance is predicted by the telomere regulatory gene POT1, which encodes a shelterin protein that sterically blocks telomerase from repairing the telomere. First, we show that lower POT1 gene expression in the blood was associated with higher female quality, that is, earlier breeding and heavier body mass. We next challenged mothers with an immune stressor (lipopolysaccharide injection) that led to “sickness” in mothers and 24 h of food restriction in their offspring. While POT1 did not respond to maternal injection, females with lower constitutive POT1 gene expression were better able to maintain feeding rates following treatment. Maternal injection also generated a 1‐day stressor for chicks, which responded with lower POT1 gene expression and elongated telomeres. Other putatively stress‐responsive mechanisms (i.e., glucocorticoids, antioxidants) showed marginal responses in stress‐exposed chicks. Model comparisons indicated that POT1 mRNA abundance was a largely better predictor of performance than telomere dynamics, indicating that telomere regulators may be powerful modulators of variation in life history strategies.

    

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