Shorter telomere length with age in the loggerhead turtle: a new hope for live sea turtle age estimation

Hatase, Hideo; Sudo, Ryusuke; Watanabe, Kunihiro; Kasugai, Takashi; Saito, Tomomi; Okamoto, Hitoshi; Uchida, Itaru; Tsukamoto, Katsumi

doi:10.1266/ggs.83.423

Cited by 26 publications

(24 citation statements)

References 17 publications

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“…Telomere length has been found to be negatively correlated with age in snakes [Bronikowski, 2008], turtles [Hatase et al, 2008], alligators [Scott et al, 2006], birds [Haussmann and Vleck, 2002;Haussmann et al, 2003], humans [Tsuji et al, 2002] and in many other taxa, so as a species that is thought to live for over 100 years [Dawbin, 1982;Castanet et al, 1988] tuatara present a good model for examining telomere length and senescence. Indeed, by comparison with other vertebrates, tuatara appear to have relatively long telomeres [H. Bender pers.…”

Section: Telomeresmentioning

confidence: 99%

The First Cytogenetic Map of the Tuatara, <i>Sphenodon punctatus</i>

O’Meally

Miller

Patel

et al. 2009

Cytogenet Genome Res

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Tuatara, Sphenodon punctatus, is the last survivor of the distinctive reptilian order Rhynchocephalia and is a species of extraordinary zoological interest, yet only recently have genomic analyses been undertaken. The karyotype consists of 28 macrochromosomes and 8 microchromosomes. A Bacterial Artificial Chromosome (BAC) library constructed for this species has allowed the first characterization of the tuatara genome. Sequence analysis of 11 fully sequenced BAC clones (∼0.03% coverage) increased the estimate of genome wide GC composition to 47.8%, the highest reported for any vertebrate. Our physical mapping data demonstrate discrete accumulation of repetitive elements in large blocks on some chromosomes, particularly the microchromosomes. We suggest that the large size of the genome (5.0 pg/haploid) is due to the accumulation of repetitive sequences. The microchromosomes of tuatara are rich in repetitive sequences, and the observation of one animal that lacked a microchromosome pair suggests that at least this microchromosome is unnecessary for survival. We used BACs bearing orthologues of known genes to construct a low-coverage cytogenetic map containing 21 markers. We identified a region on chromosome 4 of tuatara that shares homology with 7 Mb of chicken chromosome 2, and therefore the orthologous region of the snake Z chromosome. We identified a region on tuatara chromosome 3 that is orthologous to the chicken Z, and a region on chromosome 9 orthologous to the mammalian X. Since the tuatara determines sex by temperature and has no sex chromosomes, this implies that different tuatara autosome regions are homologous with the sex chromosomes of mammals, birds and snakes. We have identified anchor BAC clones that can be used to reliably mark chromosomes 3–7, 10 and 13, some of which are difficult to distinguish based on morphology alone. Fluorescence in situ hybridization mapping of 18S rDNA confirms the presence of a single NOR located on the long arm of chromosome 7, as previously identified by silver staining. Further work to construct a dense physical map will lead to a better understanding of the dynamics of genome evolution and organization in this isolated species.

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Section: Telomeresmentioning

confidence: 99%

The First Cytogenetic Map of the Tuatara, <i>Sphenodon punctatus</i>

O’Meally

Miller

Patel

et al. 2009

Cytogenet Genome Res

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“…values from both techniques showed no relationship with GLG age suggests that telomere length is not influenced by chronological age in this species. This is not the first study to report a lack of relationship between age and telomere length in a wild animal (Bize et al 2009;Hall et al 2004;Hatase et al 2008;Pauliny et al 2005) and reinforce the taxon-specific nature of these relationships. To summarize, this study has shown that AAR produces results that are similar to counting of GLGs in teeth for harp seals.…”

Section: December 2010mentioning

confidence: 49%

Harp seal ageing techniques—teeth, aspartic acid racemization, and telomere sequence analysis

Garde

Frie

Dunshea

et al. 2010

Journal of Mammalogy

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Lower jaws (containing the teeth), eyes, and skin samples were collected from harp seals (Pagophilus groenlandicus) in the southeastern Barents Sea for the purpose of comparing age estimates obtained by 3 different methods, the traditional technique of counting growth layer groups (GLGs) in teeth and 2 novel approaches, aspartic acid racemization (AAR) in eye lens nuclei and telomere sequence analyses as a proxy for telomere length. A significant correlation between age estimates obtained using GLGs and AAR was found, whereas no correlation was found between GLGs and telomere length. An AAR rate (k Asp ) of 0.00130/year 6 0.00005 SE and a D-enantiomer to L-enantiomer ratio at birth (D/L 0 value) of 0.01933 6 0.00048 SE were estimated by regression of D/L ratios against GLG ages from 25 animals (12 selected teeth that had high readability and 13 known-aged animals). AAR could prove to be useful, particularly for ageing older animals in species such as harp seals where difficulties in counting GLGs tend to increase with age. Age estimation by telomere length did not show any correlation with GLG ages and is not recommended for harp seals. DOI: 10.1644/10-MAMM-A-080.1.Key words: age determination, age estimation, amino acid racemization (AAR), aspartic acid, eye lens, growth layer group (GLG), Pagophilus groenlandicus, population management, telomere E 2010 American Society of Mammalogists Reliable methods for estimating age of animals are fundamental for life-history and population-ecology studies. Management of many harvested species (e.g., many marine mammals and ungulate species) relies on age-specific reproductive rates and survival rates to calculate sustainable harvest levels (International Council for Exploration of the Seas 2004Seas , 2008. Markers for age have been sought by examining age-related morphological changes in a variety of tissues such as teeth, claws, bones, baleen, blubber, and earplugs, and by examining molecular changes within tissues, including eye lenses, skin, blood, and blubber. Teeth have several advantages over other tissues because they do not remodel themselves like bones, nor abrade as quickly as claws or baleen (Hohn 2002). In addition, teeth are found in a wide range of marine mammals and are relatively easy to collect, store, and process for estimating age. Nevertheless, biases exist in ages derived from teeth (see below), and some species of marine mammals, such as baleen whales, have no teeth. For these reasons biologists continue to search for alternative methods for estimating the ages of marine mammals.One alternative method is called the aspartic acid racemization (AAR) technique. The rationale behind this technique is that in metabolically inactive tissues, such as eye lens nuclei, the L-enantiomer (L) of aspartic acid converts to the D-enantiomer (D) over time, a process called racemization. This racemization occurs at a constant rate throughout the life of an individual. It is therefore theoretically possible to calculate the age of an animal when the racemization rate ...

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“…Thus, it was anticipated that telomeres could provide a direct method for noninvasive estimation of animal age. However, subsequent work demonstrated that for many species of vertebrates, including reptiles (Hatase et al 2008;Scott et al 2006), birds (Bize et al 2009;Pauliny et al 2006;Salomons et al 2009), and mammals (Frenck et al 1998), telomere length and age exhibit a negative but nonlinear relationship (see Haussmann et al 2003a for a case of telomere elongation with age), making age estimation, particularly for older individuals, problematic. In 2 species of seabirds (Phalacrocorax aristotelis and Diomedea exulans) the greatest rate of telomeric attrition occurred between chick and adult stages (Hall et al 2004).…”

Section: Discussionmentioning

confidence: 99%

DNA-based approach to aging martens (Martes americanaandM. caurina)

et al. 2011

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Demographic structure is central to understanding the dynamics of animal populations. However, determining the age of free-ranging mammals is difficult, and currently impossible when sampling with noninvasive, genetic-based approaches. We present a method to estimate age class by combining measures of telomere lengths with other biologically meaningful covariates in a Bayesian network. We applied this approach to American and Pacific martens (Martes americana and M. caurina) and compared predicted age with that obtained from counts of cementum annuli. Using telomere length and the covariates sex, species, and estimates of population density obtained from commercial trapping records, we assigned martens to juvenile (,1 year) or adult (1 year) classes with 75-88% accuracy. In our analysis for live-captured martens, for which information on body size and whether animals were juveniles or adults would be available, we achieved 90-93% accuracy when assigning individuals to 5 discrete age classes (0-4+ years). This general approach could be extended to other species for noninvasive estimation of age class, or in place of invasive aging methods, and enable demographically based population analyses that have heretofore been impossible. Aging, or senescence, is the result of processes that are progressive, irreversible, and unavoidable. Although the exact physiologic and evolutionary mechanisms underlying senescence remain unclear (Williams 1999), the impacts of aging on individual fitness are well understood. Age alters an individual's physiological state and ability to respond to environmental conditions; aging reduces cognitive ability, physical stamina (MacNulty et al. 2009), and immunocompetence (Clark 2004). Because population growth is a function of age-specific fecundity and survival, accounting for age structure of sampled populations is essential. However, determining the age of free-ranging mammals is difficult. Traditionally, field biologists have used several approaches to approximate the age of animals: weighing eye lenses, measuring skeletal and cranial characteristics, and counting cementum annuli of teeth (Schroeder and Robb 2005). Although useful, these techniques are highly invasive, some requiring the sacrifice of animals, which is particularly problematic when studying threatened or endangered species.Further, such traditional approaches are unviable for the growing number of biologists using noninvasive sampling on the basis of deoxyribonucleic acid (DNA) analyses of fur, feather, skin, or scat samples. Lacking an aging technique, noninvasive studies thus far have been limited by the inability to quantify age-specific fecundity, survival or dispersal, or demographic structure.Biomedical scientists have identified a relationship between the length of telomeres-repetitive, highly conserved DNA sequences ([T 2 AG 3 ] n ) that cap the ends of eukaryotic chromosomes-and senescent processes in individuals (Frenck et al. 1998). Past work indicates that telomeres can be useful not only in understanding sene...

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Shorter telomere length with age in the loggerhead turtle: a new hope for live sea turtle age estimation

Cited by 26 publications

References 17 publications

The First Cytogenetic Map of the Tuatara, <i>Sphenodon punctatus</i>

The First Cytogenetic Map of the Tuatara, <i>Sphenodon punctatus</i>

Harp seal ageing techniques—teeth, aspartic acid racemization, and telomere sequence analysis

DNA-based approach to aging martens (Martes americanaandM. caurina)

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