Increased telomere size in sperm cells of mammals with long terminal (TTAGGG)n arrays

Telomere length in bovine sperm is related to the production of reactive oxygen species, but not to reproductive performance

“…In spite of this, data obtained in the present work through an improved qFISH method applied to decondensed sperm cells confirmed the range of absolute telomere length in bovine sperm, as figures were similar to those reported previously [35]. Furthermore, the range of telomere length in bovine sperm found herein was similar to that reported in other mammalian species using TRF, such as pigs (between 13 kb and 44 kb) [35,36] and humans (between 10 kb and 20 kb for humans) [35,37e39]. Not only do these results support that telomere length in mammalian sperm is similar across species, but also confirm the robustness of our method (i.e., qFISH in previously decondensed sperm).…”

“…While the TRF method separates telomere fragments in a pulsed field gel electrophoresis and then performs Southern blot hybridization to determine absolute telomere length, it has been reported to overestimate that variable, due to the presence of subtelomeric regions [35]. In spite of this, data obtained in the present work through an improved qFISH method applied to decondensed sperm cells confirmed the range of absolute telomere length in bovine sperm, as figures were similar to those reported previously [35]. Furthermore, the range of telomere length in bovine sperm found herein was similar to that reported in other mammalian species using TRF, such as pigs (between 13 kb and 44 kb) [35,36] and humans (between 10 kb and 20 kb for humans) [35,37e39].…”

“…This earlier study was based on the Telomere Restriction Fragment (TRF) method, which relies on the absence of restriction enzyme target sequences in telomeres. While the TRF method separates telomere fragments in a pulsed field gel electrophoresis and then performs Southern blot hybridization to determine absolute telomere length, it has been reported to overestimate that variable, due to the presence of subtelomeric regions [35]. In spite of this, data obtained in the present work through an improved qFISH method applied to decondensed sperm cells confirmed the range of absolute telomere length in bovine sperm, as figures were similar to those reported previously [35].…”

Short telomeres in short‐lived males: what are the molecular and evolutionary causes?

“…3a), suggesting that males do have the ability to maintain telomere length at a higher level than that observed in somatic tissues. On average, the mean TRF length of testes was 2.3 ± 0.6 kb (23 ± 6%) greater than the mean TRF length of somatic tissues, which is comparable to the difference in telomere length found between sperm (or testes) and somatic tissues in several vertebrate species: 14% in cattle (Kozik et al ., 1998), 24% in pigs (Kozik et al ., 1998), and 11–21% in the mouse Mus spretus (calculated from Coviello‐McLaughlin & Prowse, 1997). Only in humans does the germ‐line‐vs.‐soma difference in telomere length seem to be somewhat greater (∼39% as calculated from de Lange et al ., 1990; 69% according to Kozik et al ., 1998).…”

Telomere length positively correlates with pace‐of‐life in a sex‐ and cohort‐specific way and elongates with age in a wild mammal

“…We initially expected that this activity of telomerase would prevent telomere erosion with age. However, it could in fact be involved in the significant and consistent telomere elongation that we recorded at the within individual and population levels, as observed, for instance, in sperm of large mammals, including humans, where telomerase is maintained active (Kimura et al, 2008;Kozik et al, 1998;Ozturk, 2015;Tian et al, 2018). However, the qPCR assay did not allow us to assess the strength of this elongation, nor to compare the absolute length of telomeres recorded in this population with other studies in rodents, which could be done using the TRF or Q-FISH approaches (Lai et al, 2018;Nussey et al, 2014).…”