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Titia De Lange - One of the best experts on this subject based on the ideXlab platform.
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The DDR at Telomeres lacking intact shelterin does not require substantial chromatin decompaction.
Genes & development, 2017Co-Authors: Leonid A. Timashev, Hazen P. Babcock, Xiaowei Zhuang, Titia De LangeAbstract:Telomeres are protected by shelterin, a six-subunit protein complex that represses the DNA damage response (DDR) at chromosome ends. Extensive data suggest that TRF2 in shelterin remodels Telomeres into the t-loop structure, thereby hiding telomere ends from double-stranded break repair and ATM signaling, whereas POT1 represses ATR signaling by excluding RPA. An alternative protection mechanism was suggested recently by which shelterin subunits TRF1, TRF2, and TIN2 mediate telomeric chromatin compaction, which was proposed to minimize access of DDR factors. We performed superresolution imaging of Telomeres in mouse cells after conditional deletion of TRF1, TRF2, or both, the latter of which results in the complete loss of shelterin. Upon removal of TRF1 or TRF2, we observed only minor changes in the telomere volume in most of our experiments. Upon codeletion of TRF1 and TRF2, the telomere volume increased by varying amounts, but even those samples exhibiting small changes in telomere volume showed DDR at nearly all Telomeres. Upon shelterin removal, Telomeres underwent 53BP1-dependent clustering, potentially explaining at least in part the apparent increase in telomere volume. Furthermore, chromatin accessibility, as determined by ATAC-seq (assay for transposase-accessible chromatin [ATAC] with high-throughput sequencing), was not substantially altered by shelterin removal. These results suggest that the DDR induced by shelterin removal does not require substantial telomere decompaction.
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protection of Telomeres through independent control of atm and atr by trf2 and pot1
Nature, 2007Co-Authors: Eros Lazzerini Denchi, Titia De LangeAbstract:The Telomeres that cap normal chromosomes share virtually the same structure as damaged DNA sequences within chromosomes. So how do Telomeres evade recognition by the DNA-repair machinery? Simple: two telomere binding proteins, TRF2 and POT1, block the activation of two key DNA damage response pathways. With TRF2 and POT1 inactivated, Telomeres can be 'repaired' into the chromosomes where they don't belong. At a gross level, telomere ends resemble the ends of a double-strand break caused by DNA damage, yet Telomeres do not activate the DNA damage response. An insight is offered as to how this response is suppressed. Two telomere-binding proteins, TRF2 and POT1, inhibit the activities of two upstream 'sensor' damage-responsive kinases, ATM and ATR, respectively. As these kinases initiate the signalling cascades that provoke the repair of damaged DNA, their inhibition by TRF2 and POT1 makes the telomere ends 'invisible' to the DNA repair machinery. When Telomeres are rendered dysfunctional through replicative attrition of the telomeric DNA or by inhibition of shelterin1, cells show the hallmarks of ataxia telangiectasia mutated (ATM) kinase signalling2,3,4. In addition, dysfunctional Telomeres might induce an ATM-independent pathway, such as ataxia telangiectasia and Rad3-related (ATR) kinase signalling, as indicated by the phosphorylation of the ATR target CHK1 in senescent cells2,5 and the response of ATM-deficient cells to telomere dysfunction6,7. However, because telomere attrition is accompanied by secondary DNA damage, it has remained unclear whether there is an ATM-independent pathway for the detection of damaged Telomeres. Here we show that damaged mammalian Telomeres can activate both ATM and ATR and address the mechanism by which the shelterin complex represses these two important DNA damage signalling pathways. We analysed the telomere damage response on depletion of either or both of the shelterin proteins telomeric repeat binding factor 2 (TRF2) and protection of Telomeres 1 (POT1) from cells lacking ATM and/or ATR kinase signalling. The data indicate that TRF2 and POT1 act independently to repress these two DNA damage response pathways. TRF2 represses ATM, whereas POT1 prevents activation of ATR. Unexpectedly, we found that either ATM or ATR signalling is required for efficient non-homologous end-joining of dysfunctional Telomeres. The results reveal how mammalian Telomeres use multiple mechanisms to avoid DNA damage surveillance and provide an explanation for the induction of replicative senescence and genome instability by shortened Telomeres.
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ku70 stimulates fusion of dysfunctional Telomeres yet protects chromosome ends from homologous recombination
Nature Cell Biology, 2006Co-Authors: Giulia B Celli, Eros Lazzerini Denchi, Titia De LangeAbstract:Ku70-Ku80 heterodimers promote the non-homologous end-joining (NHEJ) of DNA breaks and, as shown here, the fusion of dysfunctional Telomeres. Paradoxically, this heterodimer is also located at functional mammalian Telomeres and interacts with components of shelterin, the protein complex that protects Telomeres. To determine whether Ku contributes to telomere protection, we analysed Ku70(-/-) mouse cells. Telomeres of Ku70(-/-) cells had a normal DNA structure and did not activate a DNA damage signal. However, Ku70 repressed exchanges between sister Telomeres - a form of homologous recombination implicated in the alternative lengthening of Telomeres (ALT) pathway. Sister telomere exchanges occurred at approximately 15% of the chromosome ends when Ku70 and the telomeric protein TRF2 were absent. Combined deficiency of TRF2 and another NHEJ factor, DNA ligase IV, did not elicit this phenotype. Sister telomere exchanges were not elevated at Telomeres with functional TRF2, indicating that TRF2 and Ku70 act in parallel to repress recombination. We conclude that mammalian chromosome ends are highly susceptible to homologous recombination, which can endanger cell viability if an unequal exchange generates a critically shortened telomere. Therefore, Ku- and TRF2-mediated repression of homologous recombination is an important aspect of telomere protection.
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recent expansion of the telomeric complex in rodents two distinct pot1 proteins protect mouse Telomeres
Cell, 2006Co-Authors: Dirk Hockemeyer, Janpeter Daniels, Hiroyuki Takai, Titia De LangeAbstract:Human Telomeres are protected by shelterin, a complex that includes the POT1 single-stranded DNA binding protein. We found that mouse Telomeres contain two POT1 paralogs, POT1a and POT1b, and we used conditional deletion to determine their function. Double-knockout cells showed that POT1a/b are required to prevent a DNA damage signal at chromosome ends, endoreduplication, and senescence. In contrast, POT1a/b were largely dispensable for repression of telomere fusions. Single knockouts and complementation experiments revealed that POT1a and POT1b have distinct functions. POT1a, but not POT1b, was required to repress a DNA damage signal at Telomeres. Conversely, POT1b, but not POT1a, had the ability to regulate the amount of single-stranded DNA at the telomere terminus. We conclude that mouse Telomeres require two distinct POT1 proteins whereas human Telomeres have one. Such divergence is unprecedented in mammalian chromosome biology and has implications for modeling human telomere biology in mice.
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dna processing is not required for atm mediated telomere damage response after trf2 deletion
Nature Cell Biology, 2005Co-Authors: Giulia B Celli, Titia De LangeAbstract:Telomere attrition and other forms of telomere damage can activate the ATM kinase pathway. What generates the DNA damage signal at mammalian chromosome ends or at other double-strand breaks is not known. Telomere dysfunction is often accompanied by disappearance of the 3' telomeric overhang, raising the possibility that DNA degradation could generate the structure that signals. Here we address these issues by studying telomere structure after conditional deletion of mouse TRF2, the protective factor at Telomeres. Upon removal of TRF2 from TRF2(F/-) p53-/- mouse embryo fibroblasts, a telomere damage response is observed at most chromosome ends. As expected, the Telomeres lose the 3' overhang and are processed by the non-homologous end-joining pathway. Non-homologous end joining of Telomeres was abrogated in DNA ligase IV-deficient (Lig4-/-) cells. Unexpectedly, the Telomeres of TRF2-/- Lig4-/- p53-/- cells persisted in a free state without undergoing detectable DNA degradation. Notably, the Telomeres retained their 3' overhangs, but they were recognized as sites of DNA damage, accumulating the DNA damage response factors 53BP1 and gamma-H2AX, and activating the ATM kinase. Thus, activation of the ATM kinase pathway at chromosome ends does not require overhang degradation or other overt DNA processing.
Marco Parolini - One of the best experts on this subject based on the ideXlab platform.
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assortative mating for telomere length and antioxidant capacity in barn swallows hirundo rustica
Behavioral Ecology and Sociobiology, 2017Co-Authors: Lela Khoriauli, Andrea Romano, Manuela Caprioli, Marco Santagostino, Solomon G Nergadze, Alessandra Costanzo, Diego Rubolini, Elena Giulotto, Nicola Saino, Marco ParoliniAbstract:The composition of breeding pairs can deviate from random, resulting in a positive association between homologous traits between mates. Assortative mating can arise either as a by-product of constraints imposed on random pairing by variation in individual life histories or because of mutual sex preferences. Because individuals that prefer high-quality mates gain fitness advantages, mate choice should result in positive assortative mating for traits that are associated with individual quality. Telomeres are nucleoprotein complexes that function to maintain chromosome integrity. Telomeres shorten at each cell division, but the rate of shortening depends on exogenous and endogenous effects, including antioxidant defense mechanisms that reduce the negative impact of pro-oxidants on telomere length. Once a critical length is attained, cells enter either senescence or apoptosis, causing a decline in tissue renewal and ultimately in individual performance. Assortative mating is therefore expected both for telomere length and for antioxidant defense because both males and females may accrue benefits from choosing a mate with long Telomeres and efficient antioxidant defense. Consistent with this prediction, in the barn swallow (Hirundo rustica), we found a positive correlation between telomere length (RTL) and total antioxidant capacity (TAC) of social mates which was not the spurious result of age or breeding date. Because parents with relatively long Telomeres produce offspring which also have relatively long Telomeres, assortative mating seems to be adaptive. The evidence of assortative mating for telomere length and antioxidant capacity suggests that epigamic signals exist that reliably reflect these traits and may mediate mutual mating preferences. Telomeres protect chromosome integrity but shorten at each cell division, impairing organismal functions. Because individuals vary in telomere length and rate of shortening, as well as in antioxidant defenses reducing the negative impact of pro-oxidants on Telomeres, adaptive mate choice should result in assortative mating for telomere length and antioxidants. Consistent with this prediction, in barn swallows, telomere length and antioxidant capacity were positively correlated between social mates.
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Assortative mating for telomere length and antioxidant capacity in barn swallows (Hirundo rustica)
'Springer Science and Business Media LLC', 2017Co-Authors: Lela Khoriauli, Andrea Romano, Manuela Caprioli, Marco Santagostino, Solomon G Nergadze, Alessandra Costanzo, Diego Rubolini, Elena Giulotto, Nicola Saino, Marco ParoliniAbstract:The composition of breeding pairs can deviate from random, resulting in a positive association between homologous traits between mates. Assortative mating can arise either as a by-product of constraints imposed on random pairing by variation in individual life histories or because of mutual sex preferences. Because individuals that prefer high-quality mates gain fitness advantages, mate choice should result in positive assortative mating for traits that are associated with individual quality. Telomeres are nucleoprotein complexes that function to maintain chromosome integrity. Telomeres shorten at each cell division, but the rate of shortening depends on exogenous and endogenous effects, including antioxidant defense mechanisms that reduce the negative impact of pro-oxidants on telomere length. Once a critical length is attained, cells enter either senescence or apoptosis, causing a decline in tissue renewal and ultimately in individual performance. Assortative mating is therefore expected both for telomere length and for antioxidant defense because both males and females may accrue benefits from choosing a mate with long Telomeres and efficient antioxidant defense. Consistent with this prediction, in the barn swallow (Hirundo rustica), we found a positive correlation between telomere length (RTL) and total antioxidant capacity (TAC) of social mates which was not the spurious result of age or breeding date. Because parents with relatively long Telomeres produce offspring which also have relatively long Telomeres, assortative mating seems to be adaptive. The evidence of assortative mating for telomere length and antioxidant capacity suggests that epigamic signals exist that reliably reflect these traits and may mediate mutual mating preferences. Significance statement: Telomeres protect chromosome integrity but shorten at each cell division, impairing organismal functions. Because individuals vary in telomere length and rate of shortening, as well as in antioxidant defenses reducing the negative impact of pro-oxidants on Telomeres, adaptive mate choice should result in assortative mating for telomere length and antioxidants. Consistent with this prediction, in barn swallows, telomere length and antioxidant capacity were positively correlated between social mates
Lela Khoriauli - One of the best experts on this subject based on the ideXlab platform.
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assortative mating for telomere length and antioxidant capacity in barn swallows hirundo rustica
Behavioral Ecology and Sociobiology, 2017Co-Authors: Lela Khoriauli, Andrea Romano, Manuela Caprioli, Marco Santagostino, Solomon G Nergadze, Alessandra Costanzo, Diego Rubolini, Elena Giulotto, Nicola Saino, Marco ParoliniAbstract:The composition of breeding pairs can deviate from random, resulting in a positive association between homologous traits between mates. Assortative mating can arise either as a by-product of constraints imposed on random pairing by variation in individual life histories or because of mutual sex preferences. Because individuals that prefer high-quality mates gain fitness advantages, mate choice should result in positive assortative mating for traits that are associated with individual quality. Telomeres are nucleoprotein complexes that function to maintain chromosome integrity. Telomeres shorten at each cell division, but the rate of shortening depends on exogenous and endogenous effects, including antioxidant defense mechanisms that reduce the negative impact of pro-oxidants on telomere length. Once a critical length is attained, cells enter either senescence or apoptosis, causing a decline in tissue renewal and ultimately in individual performance. Assortative mating is therefore expected both for telomere length and for antioxidant defense because both males and females may accrue benefits from choosing a mate with long Telomeres and efficient antioxidant defense. Consistent with this prediction, in the barn swallow (Hirundo rustica), we found a positive correlation between telomere length (RTL) and total antioxidant capacity (TAC) of social mates which was not the spurious result of age or breeding date. Because parents with relatively long Telomeres produce offspring which also have relatively long Telomeres, assortative mating seems to be adaptive. The evidence of assortative mating for telomere length and antioxidant capacity suggests that epigamic signals exist that reliably reflect these traits and may mediate mutual mating preferences. Telomeres protect chromosome integrity but shorten at each cell division, impairing organismal functions. Because individuals vary in telomere length and rate of shortening, as well as in antioxidant defenses reducing the negative impact of pro-oxidants on Telomeres, adaptive mate choice should result in assortative mating for telomere length and antioxidants. Consistent with this prediction, in barn swallows, telomere length and antioxidant capacity were positively correlated between social mates.
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Assortative mating for telomere length and antioxidant capacity in barn swallows (Hirundo rustica)
'Springer Science and Business Media LLC', 2017Co-Authors: Lela Khoriauli, Andrea Romano, Manuela Caprioli, Marco Santagostino, Solomon G Nergadze, Alessandra Costanzo, Diego Rubolini, Elena Giulotto, Nicola Saino, Marco ParoliniAbstract:The composition of breeding pairs can deviate from random, resulting in a positive association between homologous traits between mates. Assortative mating can arise either as a by-product of constraints imposed on random pairing by variation in individual life histories or because of mutual sex preferences. Because individuals that prefer high-quality mates gain fitness advantages, mate choice should result in positive assortative mating for traits that are associated with individual quality. Telomeres are nucleoprotein complexes that function to maintain chromosome integrity. Telomeres shorten at each cell division, but the rate of shortening depends on exogenous and endogenous effects, including antioxidant defense mechanisms that reduce the negative impact of pro-oxidants on telomere length. Once a critical length is attained, cells enter either senescence or apoptosis, causing a decline in tissue renewal and ultimately in individual performance. Assortative mating is therefore expected both for telomere length and for antioxidant defense because both males and females may accrue benefits from choosing a mate with long Telomeres and efficient antioxidant defense. Consistent with this prediction, in the barn swallow (Hirundo rustica), we found a positive correlation between telomere length (RTL) and total antioxidant capacity (TAC) of social mates which was not the spurious result of age or breeding date. Because parents with relatively long Telomeres produce offspring which also have relatively long Telomeres, assortative mating seems to be adaptive. The evidence of assortative mating for telomere length and antioxidant capacity suggests that epigamic signals exist that reliably reflect these traits and may mediate mutual mating preferences. Significance statement: Telomeres protect chromosome integrity but shorten at each cell division, impairing organismal functions. Because individuals vary in telomere length and rate of shortening, as well as in antioxidant defenses reducing the negative impact of pro-oxidants on Telomeres, adaptive mate choice should result in assortative mating for telomere length and antioxidants. Consistent with this prediction, in barn swallows, telomere length and antioxidant capacity were positively correlated between social mates
Sandy Chang - One of the best experts on this subject based on the ideXlab platform.
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Shelterin and the replisome: at the intersection of telomere repair and replication
Current opinion in genetics & development, 2020Co-Authors: Alessandro Cicconi, Sandy ChangAbstract:Telomeres are G-rich repetitive sequences that are difficult to replicate, resulting in increased replication stress that can threaten genome stability. Shelterin protects Telomeres from engaging in aberrant DNA repair and dictates the choice of DNA repair pathway at dysfunctional Telomeres. Recently, shelterin has been shown to participate in telomere replication. Here we review the most recent discoveries documenting the mechanisms by which shelterin represses DNA repair pathways at Telomeres while assisting its replication. The interplay between shelterin and the replisome complex highlights a novel connection between telomere maintenance and repair.
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trf2 rap1 is required to protect Telomeres from engaging in homologous recombination mediated deletions and fusions
Nature Communications, 2016Co-Authors: Rekha Rai, Yong Chen, Ming Lei, Sandy ChangAbstract:Repressor/activator protein 1 (RAP1) is a highly conserved telomere-interacting protein. Yeast Rap1 protects Telomeres from non-homologous end joining (NHEJ), plays important roles in telomere length control and is involved in transcriptional gene regulation. However, a role for mammalian RAP1 in telomere end protection remains controversial. Here we present evidence that mammalian RAP1 is essential to protect telomere from homology directed repair (HDR) of Telomeres. RAP1 cooperates with the basic domain of TRF2 (TRF2(B)) to repress PARP1 and SLX4 localization to Telomeres. Without RAP1 and TRF2(B), PARP1 and SLX4 HR factors promote rapid telomere resection, resulting in catastrophic telomere loss and the generation of telomere-free chromosome fusions in both mouse and human cells. The RAP1 Myb domain is required to repress both telomere loss and formation of telomere-free fusions. Our results highlight the importance of the RAP1-TRF2 heterodimer in protecting Telomeres from inappropriate processing by the HDR pathway.
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functional characterization of human ctc1 mutations reveals novel mechanisms responsible for the pathogenesis of the telomere disease coats plus
Aging Cell, 2013Co-Authors: Peili Gu, Sandy ChangAbstract:Coats plus is a rare recessive disorder characterized by intracranial calcifications, hematological abnormalities, and retinal vascular defects. This disease results from mutations in CTC1, a member of the CTC1–STN1–TEN1 (CST) complex critical for telomere replication. Telomeres are specialized DNA/protein structures essential for the maintenance of genome stability. Several patients with Coats plus display critically shortened Telomeres, suggesting that telomere dysfunction plays an important role in disease pathogenesis. These patients inherit CTC1 mutations in a compound heterozygous manner, with one allele encoding a frameshift mutant and the other a missense mutant. How these mutations impact upon telomere function is unknown. We report here the first biochemical characterization of human CTC1 mutations. We found that all CTC1 frameshift mutations generated truncated or unstable protein products, none of which were able to form a complex with STN1–TEN1 on Telomeres, resulting in progressive telomere shortening and formation of fused chromosomes. Missense mutations are able to form the CST complex at Telomeres, but their expression levels are often repressed by the frameshift mutants. Our results also demonstrate for the first time that CTC1 mutations promote telomere dysfunction by decreasing the stability of STN1 to reduce its ability to interact with DNA Polα, thus highlighting a previously unknown mechanism to induce telomere dysfunction.
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ctc1 deletion results in defective telomere replication leading to catastrophic telomere loss and stem cell exhaustion
The EMBO Journal, 2012Co-Authors: Jinna Min, Yang Wang, Chenhui Huang, Tao Peng, Weihang Chai, Sandy ChangAbstract:The proper maintenance of Telomeres is essential for genome stability. Mammalian telomere maintenance is governed by a number of telomere binding proteins, including the newly identified CTC1–STN1–TEN1 (CST) complex. However, the in vivo functions of mammalian CST remain unclear. To address this question, we conditionally deleted CTC1 from mice. We report here that CTC1 null mice experience rapid onset of global cellular proliferative defects and die prematurely from complete bone marrow failure due to the activation of an ATR-dependent G2/M checkpoint. Acute deletion of CTC1 does not result in telomere deprotection, suggesting that mammalian CST is not involved in capping Telomeres. Rather, CTC1 facilitates telomere replication by promoting efficient restart of stalled replication forks. CTC1 deletion results in increased loss of leading C-strand Telomeres, catastrophic telomere loss and accumulation of excessive ss telomere DNA. Our data demonstrate an essential role for CTC1 in promoting efficient replication and length maintenance of Telomeres.
Manuela Caprioli - One of the best experts on this subject based on the ideXlab platform.
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assortative mating for telomere length and antioxidant capacity in barn swallows hirundo rustica
Behavioral Ecology and Sociobiology, 2017Co-Authors: Lela Khoriauli, Andrea Romano, Manuela Caprioli, Marco Santagostino, Solomon G Nergadze, Alessandra Costanzo, Diego Rubolini, Elena Giulotto, Nicola Saino, Marco ParoliniAbstract:The composition of breeding pairs can deviate from random, resulting in a positive association between homologous traits between mates. Assortative mating can arise either as a by-product of constraints imposed on random pairing by variation in individual life histories or because of mutual sex preferences. Because individuals that prefer high-quality mates gain fitness advantages, mate choice should result in positive assortative mating for traits that are associated with individual quality. Telomeres are nucleoprotein complexes that function to maintain chromosome integrity. Telomeres shorten at each cell division, but the rate of shortening depends on exogenous and endogenous effects, including antioxidant defense mechanisms that reduce the negative impact of pro-oxidants on telomere length. Once a critical length is attained, cells enter either senescence or apoptosis, causing a decline in tissue renewal and ultimately in individual performance. Assortative mating is therefore expected both for telomere length and for antioxidant defense because both males and females may accrue benefits from choosing a mate with long Telomeres and efficient antioxidant defense. Consistent with this prediction, in the barn swallow (Hirundo rustica), we found a positive correlation between telomere length (RTL) and total antioxidant capacity (TAC) of social mates which was not the spurious result of age or breeding date. Because parents with relatively long Telomeres produce offspring which also have relatively long Telomeres, assortative mating seems to be adaptive. The evidence of assortative mating for telomere length and antioxidant capacity suggests that epigamic signals exist that reliably reflect these traits and may mediate mutual mating preferences. Telomeres protect chromosome integrity but shorten at each cell division, impairing organismal functions. Because individuals vary in telomere length and rate of shortening, as well as in antioxidant defenses reducing the negative impact of pro-oxidants on Telomeres, adaptive mate choice should result in assortative mating for telomere length and antioxidants. Consistent with this prediction, in barn swallows, telomere length and antioxidant capacity were positively correlated between social mates.
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Assortative mating for telomere length and antioxidant capacity in barn swallows (Hirundo rustica)
'Springer Science and Business Media LLC', 2017Co-Authors: Lela Khoriauli, Andrea Romano, Manuela Caprioli, Marco Santagostino, Solomon G Nergadze, Alessandra Costanzo, Diego Rubolini, Elena Giulotto, Nicola Saino, Marco ParoliniAbstract:The composition of breeding pairs can deviate from random, resulting in a positive association between homologous traits between mates. Assortative mating can arise either as a by-product of constraints imposed on random pairing by variation in individual life histories or because of mutual sex preferences. Because individuals that prefer high-quality mates gain fitness advantages, mate choice should result in positive assortative mating for traits that are associated with individual quality. Telomeres are nucleoprotein complexes that function to maintain chromosome integrity. Telomeres shorten at each cell division, but the rate of shortening depends on exogenous and endogenous effects, including antioxidant defense mechanisms that reduce the negative impact of pro-oxidants on telomere length. Once a critical length is attained, cells enter either senescence or apoptosis, causing a decline in tissue renewal and ultimately in individual performance. Assortative mating is therefore expected both for telomere length and for antioxidant defense because both males and females may accrue benefits from choosing a mate with long Telomeres and efficient antioxidant defense. Consistent with this prediction, in the barn swallow (Hirundo rustica), we found a positive correlation between telomere length (RTL) and total antioxidant capacity (TAC) of social mates which was not the spurious result of age or breeding date. Because parents with relatively long Telomeres produce offspring which also have relatively long Telomeres, assortative mating seems to be adaptive. The evidence of assortative mating for telomere length and antioxidant capacity suggests that epigamic signals exist that reliably reflect these traits and may mediate mutual mating preferences. Significance statement: Telomeres protect chromosome integrity but shorten at each cell division, impairing organismal functions. Because individuals vary in telomere length and rate of shortening, as well as in antioxidant defenses reducing the negative impact of pro-oxidants on Telomeres, adaptive mate choice should result in assortative mating for telomere length and antioxidants. Consistent with this prediction, in barn swallows, telomere length and antioxidant capacity were positively correlated between social mates
