Biology subjects

Glaberman, S.

Publications and source records attributed to Glaberman, S..

5 recordsLinked to original sources

bioRxiv2022

Cancer prevalence is remarkably low in turtles and is correlated with life history traits in birds, mammals, and squamates

Identifying species with unusually low cancer prevalence can provide new insights into cancer resistance. Most studies have focused on mammals, but the genetic, physiological, and ecological diversity among vertebrates can influence cancer susceptibility. We used necropsies from over a thousand species of amphibians, birds, crocodilians, mammals, squamates, and turtles to investigate relationships between cancer prevalence, intrinsic cancer risk, body mass, and lifespan. Previous studies often relied on species averages, leading to inaccurate interpretations. Our innovative statistical approach uses raw cancer data and resampling to improve accuracy. We found remarkably low cancer prevalence in turtles, high prevalence in squamates and mammals, and lower-than-expected prevalence based on lifespan and body mass in multiple groups. Our results show lifespan influences neoplasia and malignancy transformation rates in mammals, while body mass affects neoplasia prevalence in amphibians and squamates. These data reveal a complex relationship between life history traits and cancer risk, identifying vertebrates with potential novel cancer resistance mechanisms. STATEMENT OF SIGNIFICANCEBiodiversity is an untapped natural resource for understanding cancer. Our study reveals a wide divergence in cancer prevalence among vertebrate groups, with notably low rates in turtles and high rates in squamates and mammals. These findings can lead to new breakthroughs in understanding the biology of cancer.

evolutionary biology↗

bioRxiv2021

Hybridization and Low Genetic Diversity in the Endangered Alabama Red-Bellied Turtle (Pseudemys alabamensis)

Pseudemys alabamensis is one of the most endangered turtle species in the United States due to its small population size and restricted geographic distribution in coastal Alabama and Mississippi. Increased urbanization and climate change impacts in the region further threaten this species. Populations of P. alabamensis are geographically isolated from one another by land and salt water, which could act as barriers to intraspecific gene flow. It is currently unknown how differentiated these isolated populations are from one another or whether they have experienced reductions in population size. Previous work found morphological differences between Alabama and Mississippi populations, suggesting that they may be evolutionarily distinct. Other Pseudemys turtles such as P. concinna and P. floridana occur within the same geographic area as P. alabamensis and are known to hybridize with each other. These more abundant species could further threaten the unique genetic identity of P. alabamensis through introgression. In order to evaluate the endangered status of P. alabamensis and the level of hybridization with other species, we used the mitochondrial (mtDNA) control region and nuclear microsatellite markers to assess genetic variation within and among populations of this species throughout its range and estimate admixture with co-occurring Pseudemys species. Genetic diversity of P. alabamensis was lower than expected at both markers (no variation in mtDNA and excess of homozygosity in microsatellites). We found evidence of genetic differentiation between Alabama and Mississippi populations as well as two populations (Fowl River, Alabama and Biloxi, Mississippi) with low estimated breeding sizes and signs of inbreeding. Finally, we found evidence of admixture of P. alabamensis with P. concinna/P. floridana and Pseudemys peninsularis (a species not native to Alabama or Mississippi). Our results indicate that P. alabamensis is highly endangered throughout its range and threatened by both low population sizes and hybridization. In order to improve the species chances of survival, focus should be placed on habitat preservation, maintenance of genetic diversity within both Mississippi and Alabama populations, and regular population monitoring activities such as nest surveillance and estimates of recruitment.

evolutionary biology↗

bioRxiv2021

Concurrent evolution of anti-aging gene duplications and cellular phenotypes in long-lived turtles

There are many costs associated with increased body size and longevity in animals, including the accumulation of genotoxic and cytotoxic damage that comes with having more cells and living longer. Yet, some species have overcome these barriers and have evolved remarkably large body sizes and long lifespans, sometimes within a narrow window of evolutionary time. Here, we demonstrate through phylogenetic comparative analysis that multiple turtle lineages, including Galapagos giant tortoises, concurrently evolved large bodies, long lifespans, and reduced cancer risk. We also show through comparative genomic analysis that Galapagos giant tortoises have gene duplications related to longevity and tumor suppression. To examine the molecular basis underlying increased body size and lifespan in turtles, we treated cell lines from multiple species, including Galapagos giant tortoises, with drugs that induce different types of cytotoxic stress. Our results indicate that turtle cells, in general, are resistant to oxidative stress related to aging, while Galapagos giant tortoise cells, specifically, are sensitive to endoplasmic reticulum stress, which may give this species an ability to mitigate the effects of cellular stress associated with increased body size and longevity.

evolutionary biology↗

bioRxiv2021

Does colour impact attention towards 2D images in geckos?

Animals are exposed to different visual stimuli that influence how they perceive and interact with their environment. Visual information such as shape and colour can help the animal detect, discriminate and make appropriate behavioural decisions for mate selection, communication, camouflage, and foraging. In all major vertebrate groups, it has been shown that certain species can discriminate and prefer certain colours and that colours may increase the response to a stimulus. However, because colour is often studied together with other potentially confounding factors, it is still unclear to what extent colour discrimination plays a crucial role in the perception of and attention towards biologically relevant and irrelevant stimuli. To address these questions in reptiles, we assessed the response of three gecko species Correlophus ciliatus, Eublepharis macularius, and Phelsuma laticauda to familiar and novel 2D images in colour or grayscale. We found that while all species responded more often to the novel than to the familiar images, colour information did not influence object discrimination. We also found that the duration of interaction with images was significantly longer for the diurnal species, P. laticauda, than for the two nocturnal species, but this was independent from colouration. Finally, no differences among sexes were observed within or across species. Our results indicate that geckos discriminate between 2D images of different content independent of colouration, suggesting that colouration does not increase detectability or intensity of the response. These results are essential for uncovering which visual stimuli produce a response in animals and furthering our understanding of how animals use colouration and colour vision.

animal behavior and cognition↗

bioRxiv2019

Evaluating the Role of Fish as Surrogates for Amphibians in Pesticide Ecological Risk Assessment

Ecological risk of chemicals to aquatic-phase amphibians has historically been evaluated by comparing estimated environmental concentrations in surface water to surrogate toxicity data from standard fish species. Despite their obvious similarities, there are biological disparities among fish and amphibians that could affect their exposure and response to chemicals. Given the alarming decline in amphibians in which anthropogenic pollutants play at least some role, evaluating the potential risk of chemicals to amphibians is becoming increasingly important. Here, we evaluate relative sensitivity of fish and larval aquatic-phase amphibians to 45 different pesticides using existing data for three standardized toxicity tests: (1) amphibian metamorphosis assay (AMA) with the African clawed frog (Xenopus laevis); (2) fish short-term reproductive assay (FSTRA) with freshwater fathead minnow (Pimephales promelas); (3) fish early life stage test with P. promelas or rainbow trout (Oncorhynchus mykiss). The advantage of this dataset over previous work is that these studies show high consistency in exposure method and exposure concentration validation, study duration, test species, endpoints measured, and number of concentrations tested. We found very strong positive relationships between fish and tadpole lowest adverse effect concentrations (LOAEC) for survival (r2=0.85, slope=0.97), body weight (r2=0.77, slope=0.98), and length (r2=0.77, slope=0.92) with only one out of 45 chemicals exhibiting 100-folder greater sensitivity in frogs relative to fish. While these results suggest comparable toxicity for pesticides between these two groups of vertebrates, testing with a greater diversity of amphibians will help determine the generalizability of these results across all amphibians.\n\nDISCLAIMERThe views expressed in this manuscript are solely those of the authors and do not represent the policies of the U.S. Environmental Protection Agency. Mention of trade names of commercial products should not be interpreted as an endorsement by the U.S. Environmental Protection Agency.

pharmacology and toxicology↗