Herbal species authentication by melting fingerprint coupled with high resolution melting analysis (MF-HRM).

BACKGROUND: Herbal medicines have recently attracted increasing attention for use as food supplements with health benefits; however, species authentication can be difficult due to incomplete morphological characters. Here, a molecular tool was developed for the identification of species in the National List of Essential Medicinal Plants in Thailand. METHODS: The identification process used DNA fingerprints including start codon targeted (SCoT) and inter simple sequence repeat (ISSR) polymorphisms, coupled with high resolution melting (HRM), to produce melting fingerprint (MF)-HRM. RESULTS: Results indicated that MF-HRM, SCoT-HRM and ISSR-HRM could be used for DNA fingerprints as S34, S36, S9 and S8 of SCoT and UBC873, S25 and UBC841 of ISSR. The melting fingerprints obtained from S34 of SCoT exhibited the best primers for identification of herbal species with 87.5% accuracy and relatively high repeatability. The presence of intraspecific variation in a few species affected the shift of melting fingerprints within species. MF-HRM using S34 showed improved species prediction compared to DNA fingerprints. The concentration of DNA with 10 ng/µl was recommended to perform MF-HRM. MF-HRM enabled species authentication of herbal commercialized products at only 20% resulting from the low quality of DNA isolated, while admixture of multiple product species interfered with the MF process. CONCLUSION: Findings suggested that MF-HRM showed promise as a molecular tool for the authentication of species in commercial herbal products with high specificity, moderate repeatability and rapidity without prior sequence information. This information will greatly improve quality control and traceability during the manufacturing process.

Differentiating paramphistome species in cattle using DNA barcoding coupled with high-resolution melting analysis (Bar-HRM).

Paramphistomosis is caused by paramphistome or amphistome parasites, including Fischoederius elongatus, Gastrothylax crumenifer, Orthocoelium parvipapillatum, and Paramphistomum epiclitum. The control and prevention of these parasite outbreaks are difficult because of the wide occurrence of these species. Besides, the clinical manifestations and their egg characteristics are similar to those of other intestinal flukes in the paramphistome group, leading to misdiagnosis. Here, we employed DNA barcoding using NADH dehydrogenase (ubiquinone, alpha 1) (ND1) and cytochrome c oxidase subunit I (COI), coupled with high-resolution melting analysis (Bar-HRM), for species differentiation. As a result, ParND1_3 and ParCOI4 resulted in positive amplification in the paramphistomes and Fasciola gigantica, with significantly different melting curves for each species. The melting temperatures of each species obtained clearly differed. Regarding sensitivity, the limit of detection (LoD) for all species of paramphistomes was 1 pg/µl. Our findings suggest that Bar-HRM using ParND1_3 is highly suitable for the differentiation of paramphistome species. This approach can be used in parasite detection and epidemiological studies in cattle.

Isothermal Detection of Canine Blood Parasite (Ehrlichia canis) Utilizing Recombinase Polymerase Amplification Coupled with Graphene Oxide Quenching-Based Pyrrolidinyl Peptide Nucleic Acid.

Canine monocytic ehrlichiosis (CME), caused by transmitted Ehrlichia canis infection, is a major disease in dogs with worldwide distribution. Herein, a nucleic acid assay was established for the identification of E. canis infection employing a fluorescently labeled conformationally constrained pyrrolidinyl PNA probe (Flu-acpcPNA) designed to sequence-specifically target the 16S rRNA gene. The sensing principle is based on the excellent quenching ability of graphene oxide (GO) of the free PNA probe, that was diminished upon binding to the DNA target. The addition of DNase I improved the performance of the detection system by eliminating the nonspecific quenching capability of long-chain dsDNA and thus enhancing the fluorescence signaling. The assay was coupled with a recombinase polymerase amplification (RPA) technique, which could be performed under isothermal conditions (37 °C) without DNA denaturation and purification steps. The established method is simple to set up and execute, proving a rapid, specific, and sensitive detection of 16S rRNA gene of E. canis with a limit of detection at least 11.1 pM. This technique shows good potential for the visual detection of double-stranded DNA targets without the need for PCR or complicated instruments, which shows great promise for practical usage in resource limited areas.

Is species identification of Echinostoma revolutum using mitochondrial DNA barcoding feasible with high-resolution melting analysis?

The taxonomic evaluation of Echinostoma species is controversial. Echinostoma species are recognized as complex, leading to problems associated with accurate identification of these species. The aim of this study was to test the feasibility of using DNA barcoding of cytochrome c oxidase subunit I (COI) and NADH dehydrogenase subunit 1 (ND1) conjugated with high-resolution melting (HRM) analysis to identify Echinostoma revolutum. HRM using COI and ND1 was unable to differentiate between species in the "revolutum complex" but did distinguish between two isolates of 37-collar-spined echinostome species, including E. revolutum (Asian lineage) and Echinostoma sp. A from different genera, e.g., Hypoderaeum conoideum, Haplorchoides mehrai, Fasciola gigantica, and Thapariella anastomusa, based on the Tm values derived from HRM analysis. Through phylogenetic analysis, a new clade of the cryptic species known as Echinostoma sp. A was identified. In addition, we found that the E. revolutum clade of ND1 phylogeny obtained from the Thailand strain was from a different lineage than the Eurasian lineage. These findings reveal the complexity of the clade, which is composed of 37-collar-spined echinostome species found in Southeast Asia. Taken together, the systematic aspects of the complex revolutum group are in need of extensive investigation by integrating morphological, biological, and molecular features in order to clarify them, particularly in Southeast Asia.

Osteoarthritis in two marine mammals and 22 land mammals: learning from skeletal remains.

The occurrence of osteoarthritis (OA) in marine mammals is still questionable. Here we investigated the prevalence of OA in marine (dolphin and dugong) and terrestrial mammals (Asian elephant, Asiatic buffalo, camel, cat, cattle, deer, dog, domestic goat, horse, human, hyena, impala, lion, Malayan tapir, Assam macaque, mule, pig, rabbit, red kangaroo, sheep, tiger and waterbuck). Skeletal remains obtained from five institutes were used as subjects; a total of 45 different parts (locations) of bones were observed for OA lesions. The prevalence of OA was reported as number of OA lesions/total number of bones. Our results revealed that the presence of OA in marine species (dolphin and dugong) was 2.44% and 3.33%, respectively. In dolphins, the highest OA occurrence was on the left and right humeral trochlea, with 13.68% and 12.63%, respectively, while the highest number of OA lesions in dugongs was on the lumbar vertebrae (8.79%). No significant difference (P > 0.05) in the prevalence of OA between sexes in dolphins and dugongs was observed, but we found a significant difference (P < 0.05) in 24 bone locations of human bones, which had the highest OA prevalence (48.93%), followed by dogs (3.94%). In conclusion, OA can occur in marine mammals, similar to terrestrial mammals, even though their natural habitat is the ocean.

In Vitro Chondroprotective Potential of Extracts Obtained from Various Phyllantus Species.

Phyllanthus amarus has been proven to exhibit chondroprotection. Regarding the morphological similarities among Phyllanthus species, we were attracted to evaluate the chondroprotective potential of Phyllanthus species including P. amarus obtained from Chiang Mai and Phuket, Phyllanthus urinaria L., Phyllanthus urinaria subsp. chamaepeuce, Phyllanthus debilis, and Phyllanthus airy-shawii using interleukin-1ß-induced degradation of cartilage explants. The ethanolic extracts of the plants were evaluated for major lignans, phyllanthin, and hypophyllanthin by HPLC and further measurements of the total contents of flavonoids and phenolic compounds along with the assays for antioxidant and anti-collagenase activities. The interleukin-1ß-induced cartilage explant degradation was performed with/without the extracts at concentrations of 50-250 µg/mL. After 4-14 days of incubation, the medium was assayed for the level of sulfated glycosaminoglycans while the explants were measured for the remaining content of uronic acid. Proteoglycan intensity in the explants was determined by safranin O staining. Diacerein, the antiarthritic agent, was used as the positive control. Although the two major lignans were found in P. amarus from Chiang Mai, P. amarus from Phuket, and P. urinaria L. extracts, similar chondroprotective activities were observed in all Phyllanthus extracts. Total phenolic content and total flavonoid content of the extracts showed a correlation with antioxidation, whereas the total phenolic content correlated with anti-collagenase activity. Among the six extracts, P. airy-shawii showed the greatest antioxidant and collagenase inhibitory activities. The results revealed that chondroprotective activities of all of the extracts of Phyllanthus species might result from an additive or synergistic influence of some constituents of these plants, which could be considered for antiarthritic purposes.

Harnessing postharvest light emitting diode (LED) technology of Centella asiatica (L.) Urb. to improve centelloside content by up-regulating gene expressions in the triterpenoid pathway.

Centella asiatica (L.) Urb. has wound healing, anti-inflammatory, cognitive improvement, and neuroprotective properties which have been attributed to its centelloside content. However, the quantities of these bioactive compounds are limited and vary due to genetic and environmental factors. Light qualities are known to enhance the production of secondary metabolites in several plant species, both preharvest and postharvest. In this study, fresh leaves of C. asiatica were subjected to different light emitting diode (LED) quality including white, dark, red, blue, and green to assess centelloside content, phytochemical constituents, and transcription level expression of triterpenoid biosynthesis genes. Results showed that white and blue LEDs significantly increased centelloside content in C. asiatica leaves at 3 days postharvest (dph) by 73 % over the control group at 0 dph. Blue LEDs stimulated the expression of triterpenoid biosynthesis genes including C. asiatica squalene synthase (CaSQS), C. asiatica ß-amyrin synthase (CabAS), and C. asiatica UDP gluclosyltransferase-73AH1 (CaUGT73AH1; CaUGT), while different LED conditions gave diverse results. Red LED treatment triggered higher total flavonoid content (TFC) and total triterpenoid content (TTC) while white LEDs enhanced total triterpenoid content (TTC). Taken together, our findings suggest that postharvest under blue LEDs is a great approach to increase centelloside production of C. asiatica through gene up-regulation in triterpenoid pathway. Therefore, postharvest technology by LEDs serves as an effective tool for improving raw material quality for medicinal plant industries.

Integration of IFAST-based nucleic acid extraction and LAMP for on-chip rapid detection of Agroathelia rolfsii in soil.

Agroathelia rolfsii (A. rolfsii) is a fungal infection and poses a significant threat to over 500 plant species worldwide. It can reduce crop yields drastically resulting in substantial economic losses. While conventional detection methods like PCR offer high sensitivity and specificity, they require specialized and expensive equipment, limiting their applicability in resource-limited settings and in the field. Herein, we present an integrated workflow with nucleic acid extraction and isothermal amplification in a lab-on-a-chip cartridge based on immiscible filtration assisted by surface tension (IFAST) to detect A. rolfsii fungi in soil for point-of-need application. Our approach enabled both DNA extraction of A. rolfsii from soil and subsequent colorimetric loop-mediated isothermal amplification (LAMP) to be completed on a single chip, termed IFAST-LAMP. LAMP primers targeting ITS region of A. rolfsii were newly designed and tested. Two DNA extraction methods based on silica paramagnetic particles (PMPs) and three LAMP assays were compared. The best-performing assay was selected for on-chip extraction and detection of A. rolfsii from soil samples inoculated with concentrations of 3.75, 0.375 and 0.0375 mg fresh weight per 100-g soil (%FW). The full on-chip workflow was achieved within a 1-h turnaround time. The platform was capable of detecting as low as 3.75 %FW at 2 days after inoculation and down to 0.0375 %FW at 3 days after inoculation. The IFAST-LAMP could be suitable for field-applicability for A. rolfsii detection in low-resource settings.

A modified colorimetric method of gelatinolytic assay using bacterial collagenase type II as a model.

Coomassie brilliant blue (CBB) heated by microwave was used as a staining dye for measuring gelatinolytic activity. The quantity of gelatin remaining after incubation with bacterial collagenase was determined using the heated CBB, resulting in visible blue pellets. Dimethyl sulfoxide was added to dissolve the dye and measurement of the absorbance at 600 nm was done to detect the level of gelatin (up to 10 µg), with the limit of detection for the amount of collagenase at 50 ng. This approach is rapid, simple, and economic for the purpose of screening for pharmaceutical agents that possess inhibitory activity on collagenase.

RPA/CRISPR-cas12a as a specific, sensitive and rapid method for diagnosing Ehrlichia canis and Anaplasma platys in dogs in Thailand.

Rickettsial pathogens including Ehrlichia canis and Anaplasma platys are bacteria that cause parasitic infections in dogs such as canine monocytic ehrlichiosis (CME) and canine cyclic thrombocytopenia (CCT), respectively affecting mortality and morbidity worldwide. An accurate, sensitive, and rapid method to diagnose these agents is essential for effective treatment. In this study, a recombinase polymerase amplification (RPA) coupled with CRISPR-Cas12a methods was established to detect E. canis and A. platys infection in dogs based on the 16S rRNA. The optimal condition for DNA amplification by RPA was 37 °C for 20 min, followed by CRISPR-Cas12a digestion at 37 °C for one hour. A combination of RPA and the cas12a detection method did not react with other pathogens and demonstrated strong sensitivity, detecting as low as 100 copies of both E. canis and A. platys. This simultaneous detection method was significantly more sensitive than conventional PCR. The RPA-assisted cas12a assay provides specific, sensitive, rapid, simple and appropriate detection of rickettsial agents in canine blood at the point-of-care for diagnostics, disease prevention and surveillance.

Structure-Activity Relationship and Molecular Docking of Quinazolinones Inhibiting Expression of COX-2, IL-1ß, iNOS, and TNF-α through NF-κB Pathways.

The quinazolinone scaffold is found in natural products and biologically active compounds, including inflammatory inhibitors. Major proteins or enzymes involved in the inflammation process are regulated by the amount of gene expression. Quinazolinone derivatives were investigated and developed against the inflammatory genes cyclooxygenase-2 (COX-2), interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), and inducible nitric oxide synthase (iNOS) in the lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cell line. The mRNA expressions were measured using a real-time quantitative polymerase chain reaction (RT-qPCR). Quinazolinone compounds at 62.5 µM demonstrated anti-COX-2 and anti-IL-1ß mRNA expressions down to 0.50% and 3.10% gene expression, respectively, via inhibition of nuclear factor κB (NF-κB). Molecular docking was performed to explain the interaction between the binding site and the developed compounds as well as the structure-activity relationship of the quinazolinone moiety.

Cryptochrome and quantum biology: unraveling the mysteries of plant magnetoreception.

Magnetoreception, the remarkable ability of organisms to perceive and respond to Earth's magnetic field, has captivated scientists for decades, particularly within the field of quantum biology. In the plant science, the exploration of the complicated interplay between quantum phenomena and classical biology in the context of plant magnetoreception has emerged as an attractive area of research. This comprehensive review investigates into three prominent theoretical models: the Radical Pair Mechanism (RPM), the Level Crossing Mechanism (LCM), and the Magnetite-based MagR theory in plants. While examining the advantages, limitations, and challenges associated with each model, this review places a particular weight on the RPM, highlighting its well-established role of cryptochromes and in-vivo experiments on light-independent plant magnetoreception. However, alternative mechanisms such as the LCM and the MagR theory are objectively presented as convincing perspectives that permit further investigation. To shed light on these theoretical frameworks, this review proposes experimental approaches including cutting-edge experimental techniques. By integrating these approaches, a comprehensive understanding of the complex mechanisms driving plant magnetoreception can be achieved, lending support to the fundamental principle in the RPM. In conclusion, this review provides a panoramic overview of plant magnetoreception, highlighting the exciting potential of quantum biology in unraveling the mysteries of magnetoreception. As researchers embark on this captivating scientific journey, the doors to deciphering the diverse mechanisms of magnetoreception in plants stand wide open, offering a profound exploration of nature's adaptations to environmental cues.

The first study of genetic diversity and population structure of Indo-Pacific bottlenose dolphin (Tursiops aduncus) and pantropical spotted dolphin (Stenella attenuata) in the Thai Andaman Sea based on ISSR.

Background and Aim: The Indo-Pacific bottlenose dolphin, Tursiops aduncus, and the pantropical spotted dolphin, Stenella attenuata, are protected marine mammals in Thailand; however, knowledge regarding the populations of both species in Thai seas is minimal. We aimed to reveal the genetic diversity and population structure of two species, T. aduncus, and S. attenuata, based on inter-simple sequence repeats (ISSRs). Materials and Methods: Samples of stranded T. aduncus (n = 30) and S. attenuata (n = 23) found along Thai Andaman Sea coasts from 1998 to 2018 were used in this study. A total of 17 and 16 ISSR primers that produced clear and polymorphic bands were selected for T. aduncus and S. attenuata, respectively. Results: The highest percentages of polymorphic bands for T. aduncus and S. attenuata were 93.750% and 92.857%, respectively. Phylogenetic dendrograms indicated that the population of each species was clustered into three groups. This outcome was consistent with the genetic population structure, as both suggested three genetic clusters (DK = 3). Genetic diversity analysis revealed that the average Shannon's information index (I) was 1.926 ± 0.066 for T. aduncus and 1.714 ± 0.090 for S. attenuata, which indicate a high level of genetic variation. Further, low fixation index (F) values were observed for T. aduncus and S. attenuata at -0.231 ± 0.024 and -0.312 ± 0.042, respectively, suggesting that inbreeding is unlikely to have occurred for both species over the past decades. Conclusion: At least three genetic clusters of both species were found in the Thai Andaman Sea, and the diversity indices of each species indicated that these species are not at a critical level for extinction. However, monitoring their population status should be prioritized to observe any future changes in the level of diversity.

Relationship of stranded cetaceans in Thai territorial waters to global populations: Mitochondrial DNA diversity of Cuvier's beaked whale, Indo Pacific finless porpoise, pygmy sperm whale, and dwarf sperm whale.

Cetaceans inhabit oceans throughout the world. Four specific odontocetes, namely Cuvier's beaked whale (Ziphius cavirostris), Indo Pacific finless porpoise (Neophocaena phocaenoides), pygmy sperm whale (Kogia breviceps), and dwarf sperm whale (Kogia sima), have occasionally been found stranded along Thailand's coastal waters (the Andaman Sea and the Gulf of Thailand). Although shared haplotypes of each species for many locations have been found, and some species have revealed genetic structure through haplotype networks, cetaceans in Thai waters have never been investigated in terms of comparing haplotypes to those that have existed before. Herein, we have illustrated the matrilineally phylogeographic relationships among worldwide populations through Bayesian Phylogenetic tree computations using Markov Chain Monte Carlo (MCMC) and Median-Joining Networks (MJNs). Unique haplotypes of the control region mitochondrial DNA of Thai odontocetes were found for all species. Moreover, a high degree of worldwide haplotype diversity (hd) above 0.8 among the four species was detected, while the lowest degree of nucleotide diversity (π) was observed in the Indo Pacific finless porpoise (1.12% ± 0.184%). An expansion of the effective female population size worldwide of three odontocete species was detected using Bayesian Skyline Reconstruction, but this did not include the Indo Pacific finless porpoise. Because Thai seas are located within the Indo Polynesian province, where this biodiversity hotspot exists, we speculate that these odontocetes may also inhabit specific habitats within the Malay Peninsula and Thailand's territorial waters. Therefore, closer attention and monitoring of these cetacean populations will be necessary for future conservation efforts.

Microsatellite Polymorphism and the Population Structure of Dugongs (Dugong dugon) in Thailand.

The dugong (Dugong dugon) is an endangered species of marine mammals, so knowledge of genetic diversity of these populations is important for conservation planning within different habitats. In this study, six microsatellite markers were used to assess the genetic diversity and population structure of 77 dugongs from skin samples of stranded animals collected from 1994-2019 (69 from Andaman Sea and 8 from the Gulf of Thailand). Our results found that dugongs in the Andaman Sea had higher genetic variation than those in the Gulf of Thailand. Populations in Trang, Satun, and some areas of Krabi had highest diversity compared to other regions of Thailand. Bayesian genetic clustering analysis revealed that dugongs in Thailand consist of five genetic groups. Moreover, dugongs in the middle and lower Andaman Sea presented the greatest gene flow compared to other regions. However, based on calculation of inbreeding coefficients (Fis value = 0.239), dugong populations in the Sea of Thailand are experiencing some levels of inbreeding, and so may warrant special protections. These results provide important information for understanding the genetic status of dugongs that can lead to improved management and conservation of this endangered species.

Sensitive and rapid detection of Babesia species in dogs by recombinase polymerase amplification with lateral flow dipstick (RPA-LFD).

Canine babesiosis is a tick-borne disease caused by Babesia spp., which infects and destroys healthy erythrocytes, leading to mortality and morbidity in dogs. The diagnosis of babesiosis is tedious and time-consuming, especially in latent and chronic infections. Here, a recombinase polymerase amplification combined with a lateral flow dipstick (RPA-LFD) assay was developed for rapid and accurate detection of Babesia spp. in canine blood specimens based on the 18S rRNA region. The RPA-LFD assay using rpaBab264 gave specificity to Babesia spp. in dogs (B. vogeli and B. gibsoni) without cross-amplification to other parasites (apicomplexans and non-apicomplexans), with detection limit of at least 22.5 copies/µl (0.1 fg/µl) at 40 °C for at least 10 min. The whole process of DNA amplification by RPA and readout by LFD did not exceed 30 min. To determine the performance of the RPA-LFD assay, a total of 30 clinical samples was examined and compared with conventional PCR (cPCR) and multiplex HRM (mHRM). Eight dogs (26.67%) were detected as positive by RPA-LFD, while seven and six were found positive by cPCR and mHRM, respectively. RPA-LFD and cPCR showed high agreement with Babesia spp. detection with kappa > 0.9. We confirmed that the dogs were infected by B. vogeli from sequences of positive PCR results. Our findings suggested that RPA-LFD using the rpaBab264 assay offered a rapid, accurate, cost-effective and simple method for Babesia spp. detection that is feasibly applicable to be rapid kit at a pet hospital or point-of-care testing.

Elemental Distribution in Animal Carpal and Tarsal Bones Using Differences in X-ray Fluorescence Energy.

Little is known as to whether different operating voltages of X-ray fluorescence (XRF) can affect the accuracy rate for species identification. Here, we have addressed this question by comparing the rate of correct species identification using the elemental composition of either the carpal or tarsal bone obtained from a determination of the different energy values of XRF at 15 and 50 kV using energy-dispersive XRF (ED-XRF). Carpal bones were taken from 16 species and tarsal bones from 11 of these species. The data on the elemental profiles were analyzed by stepwise discriminant analysis for species discrimination. The classification results indicated that 94.1% and 63.7% of the originally grouped cases were correctly classified as carpal bones using 15 kV and 50 kV, respectively. Additionally, 69.4% and 77.3% of the originally grouped cases were correctly classified as tarsal bones using 15 kV and 50 kV, respectively. When the datasets of the elemental profiles obtained using two operating voltages were gathered, the classification results of the prediction rate appeared to be more accurate at 89.7% and 90.7% in the carpal and tarsal bones, respectively. In conclusion, our findings suggest that the elemental profiles of bones obtained using two operating voltages could effectively facilitate accurate species discrimination.

Bar-cas12a, a novel and rapid method for plant species authentication in case of Phyllanthus amarus Schumach. & Thonn.

Rapid and accurate species diagnosis accelerates performance in numerous biological fields and associated areas. However, morphology-based species taxonomy/identification might hinder study and lead to ambiguous results. DNA barcodes (Bar) has been employed extensively for plant species identification. Recently, CRISPR-cas system can be applied for diagnostic tool to detect pathogen's DNA based on the collateral activity of cas12a or cas13. Here, we developed barcode-coupled with cas12a assay, "Bar-cas12a" for species authentication using Phyllanthus amarus as a model. The gRNAs were designed from trnL region, namely gRNA-A and gRNA-B. As a result, gRNA-A was highly specific to P. amarus amplified by RPA in contrast to gRNA-B even in contaminated condition. Apart from the large variation of gRNA-A binding in DNA target, cas12a- specific PAM's gRNA-A as TTTN can be found only in P. amarus. PAM site may be recognized one of the potential regions for increasing specificity to authenticate species. In addition, the sensitivity of Bar-cas12a using both gRNAs gave the same detection limit at 0.8 fg and it was 1,000 times more sensitive compared to agarose gel electrophoresis. This approach displayed the accuracy degree of 90% for species authentication. Overall, Bar-cas12a using trnL-designed gRNA offer a highly specific, sensitive, speed, and simple approach for plant species authentication. Therefore, the current method serves as a promising tool for species determination which is likely to be implemented for onsite testing.

Life Expectancy in Marine Mammals Is Unrelated to Telomere Length but Is Associated With Body Size.

Marine mammals vary greatly in size and lifespan across species. This study determined whether measures of adult body weight, length and relative telomere length were related to lifespan. Skin tissue samples (n = 338) were obtained from 23 marine mammal species, including four Mysticeti, 19 Odontoceti and one dugong species, and the DNA extracted to measure relative telomere length using real-time PCR. Life span, adult body weight, and adult body length of each species were retrieved from existing databases. The phylogenetic signal analysis revealed that body length might be a significant factor for shaping evolutionary processes of cetacean species through time, especially for genus Balaenoptera that have an enormous size. Further, our study found correlations between lifespan and adult body weight (R 2 = 0.6465, p < 0.001) and adult body length (R 2 = 0.6142, p ≤0.001), but no correlations with relative telomere length (R 2 = -0.0476, p = 0.9826). While data support our hypothesis that larger marine mammals live longer, relative telomere length is not a good predictor of species longevity.