Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 8 de 8
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
PeerJ ; 11: e16516, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38107575

RESUMEN

Livestock depredation by leopards is a pervasive issue across many Asian and African range countries, particularly in and around protected areas. Developing effective conflict mitigation strategies requires understanding the landscape features influencing livestock depredation. In this study, we investigated predictors associated with livestock depredation by leopards using 274 cases of leopard attacks on livestock that occurred between 2017 and 2020 in the Annapurna Conservation Area, Nepal. We also examined how livestock predation by leopards varied depending on the species, season, and time. A generalized linear model with binary logistic regression was used to test the statistical significance of variables associated with the presence and absence of conflict sites. The results revealed that the area of forest, agricultural land, length of rivers, slope, proximity to settlements and protected areas, and elevation significantly predicted the probability of leopard attacks on livestock. We also observed a significant increase in the incidence of leopard predation on livestock with decreasing slopes and rising elevations. The areas near human settlements and the protected areas faced a higher risk of leopard predation. The incidence of leopard predation on livestock varied significantly depending on the livestock species, season, and time. Goats were the most highly predated livestock, followed by sheep, cow/ox, and buffalo. A total of 289.11 km2 (or around 5% of the research area) was deemed to be at high risk for leopard predation on livestock. This study's comprehensive understanding of human-leopard conflicts provides valuable insights for planning and implementing measures to reduce damage caused by leopard populations throughout their range.


Asunto(s)
Ganado , Panthera , Femenino , Bovinos , Animales , Humanos , Ovinos , Ecosistema , Nepal , Conservación de los Recursos Naturales , Cabras
2.
Sci Rep ; 10(1): 21607, 2020 12 10.
Artículo en Inglés | MEDLINE | ID: mdl-33303852

RESUMEN

Defining conservation units is an important step in species management and requires interpretation of the genetic diversity and ecological function of the taxon being considered. We used the endemic Cuban Rock Iguanas (Cyclura nubila nubila) as a model to highlight this challenge and examined patterns of its intraspecific genetic diversity across Cuba. We evaluated nuclear (microsatellite loci) and mitochondrial diversity across eight populations from the island and its off-shore cays, and applied the population genetics results for assignment of Management Unit (MU) status and Evolutionary Significant Units (ESUs) based on phylogeographic and time of divergence information. We identified at least six distinct Cuban Rock Iguana MUs, encompassing demographically isolated and genetically differentiated populations across Cuba, most with low effective population size, declining populations, and with high risk of inbreeding and genetic drift. Hence, each MU should be considered of urgent conservation priority. Given the key ecological seed dispersal role of C. n. nubila, the disappearance of any MU could trigger the loss of local ecological functional diversity and major negative impacts on their ecosystems. Two divergent ESUs were also identified, exhibiting an historical east-west geographic separation on Cuba. Based on a Caribbean phylogeographic assessment, our findings strengthen the conclusion that all geographically and evolutionarily differentiated Cyclura species and subspecies across the archipelago warrant ESU distinction.


Asunto(s)
Conservación de los Recursos Naturales/métodos , Iguanas/clasificación , Animales , Cuba , Ecosistema , Genética de Población , Iguanas/genética , Repeticiones de Microsatélite/genética , Filogeografía
3.
Zookeys ; 995: 127-153, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33281471

RESUMEN

Lizards of the genus Dendragama are endemic to the highland cloud forests of Sumatra's Barisan Mountain Range in western Indonesia, and recent studies have uncovered widespread diversity within the genus. Here, a suite of morphological characters and mitochondrial DNA are used to compare three geographically isolated populations of D. boulengeri from (1) Mount Kerinci in Jambi province, (2) Mount Marapi of west Sumatra, and (3) the Karo Highlands of north Sumatra. Additional phylogeographic analyses with two recently described sister species, D. australis and D. dioidema were conducted. Five genetically distinct clades of Dendragama, all distributed allopatrically of one another were identified and some are suspected to inhabit small distributions. Morphological and genetic data confirm the Karo Highlands population D. schneideri (previously Acanthosaura schneideri Ahl, 1926) should be revalidated from the synonymy of D. boulengeri. Dendragama schneideri is endemic to montane forests of the Karo Highlands surrounding Lake Toba in Sumatra Utara province. Pairwise genetic distances of 6-11% separate D. schneideri from congeners. Two distinct clades of D. boulengeri from Mount Kerinci and Mount Marapi were identified, which are 5.0% genetically distant from one another. Using morphological characters, we provide the first key for distinguishing between species of Dendragama. Based on biogeographic patterns and levels of genetic variation it is suspected that at least 18 other isolated cloud forest locations may hold new species or divergent populations of Dendragama but lack survey work. Collectively, these comparisons among populations of montane lizards further elucidate the complex biogeographic history of Sumatra's montane forest species and the first phylogeny of the genus Dendragama.

4.
Mol Ecol ; 29(16): 2994-3009, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32633832

RESUMEN

Catastrophic events, such as volcanic eruptions, can have profound impacts on the demographic histories of resident taxa. Due to its presumed effect on biodiversity, the Pleistocene eruption of super-volcano Toba has received abundant attention. We test the effects of the Toba eruption on the diversification, genetic diversity, and demography of three co-distributed species of parachuting frogs (Genus Rhacophorus) on Sumatra. We generate target-capture data (~950 loci and ~440,000 bp) for three species of parachuting frogs and use these data paired with previously generated double digest restriction-site associated DNA (ddRADseq) data to estimate population structure and genetic diversity, to test for population size changes using demographic modelling, and to estimate the temporal clustering of size change events using a full-likelihood Bayesian method. We find that populations around Toba exhibit reduced genetic diversity compared with southern populations, and that northern populations exhibit a shift in effective population size around the time of the eruption (~80 kya). However, we infer a stronger signal of expansion in southern populations around ~400 kya, and at least two of the northern populations may have also expanded at this time. Taken together, these findings suggest that the Toba eruption precipitated population declines in northern populations, but that the demographic history of these three species was also strongly impacted by mid-Pleistocene forest expansion during glacial periods. We propose local rather than regional effects of the Toba eruption, and emphasize the dynamic nature of diversification on the Sunda Shelf.


Asunto(s)
Anuros , Aviación , Animales , Anuros/genética , Teorema de Bayes , ADN Mitocondrial/genética , Bosques , Variación Genética , Indonesia , Filogenia
5.
Mol Phylogenet Evol ; 149: 106840, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32305510

RESUMEN

Biogeographical evidence, both, for and against the "regional endemism paradigm" hypothesis has been uncovered across the Greater Sunda Region (Sundaland) of Southeast Asia. Additionally, there are competing hypotheses regarding how Pleistocene forests may have impacted biological patterns and processes in Sumatra. Using montane agamid lizards from Sumatra, we derived and analyzed a phylogenetic dataset, genetic divergence estimates, and contemporary distributional patterns among species. We tested whether (1) Sumatra's highland Draconinae diversification fits the regional endemism paradigm hypothesis and (2) Draconinae phylogeography provides biological evidence for Pleistocene forest extent at various points in history. Our results suggest in situ diversification was the main driver behind montane Draconinae lizard diversification in Sumatra, rejecting the "regional endemism paradigm". Contemporary distribution of endemic species and their genetic relationships may potentially provide biologicalevidence for determining more precise elevational lower limits of montane forests during the Pleistocene epoch. Our data suggests montane forests did not retreat more than 700-750 m during glacial maxima because lower retreating forests would have become interconnected, allowing for widespread dispersal, exchange of gene flow and sympatric distributions contemporarily. To the contrary, our divergence estimates show that cloud forest dragons have been isolated for millions of years, suggesting there may have been a continuous disconnect between some areas, predating the Pleistocene. There may also be other ecological and evolutionary factors that impacted Draconinae distributions, such as competition, making this an excellent system for testing questions regarding montane biogeography. Additionally, we provide the first phylogeny for a wide range of Sundaland agamid species and identify some biogeographic pressures that may have triggered montane Draconinae diversification in Sumatra.


Asunto(s)
Biodiversidad , Bosques , Lagartos/clasificación , Filogeografía , Animales , Flujo Génico , Genoma Mitocondrial , Indonesia , Lagartos/genética , Filogenia
6.
Mol Biol Evol ; 32(1): 173-83, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25338510

RESUMEN

Snake venom gene evolution has been studied intensively over the past several decades, yet most previous studies have lacked the context of complete snake genomes and the full context of gene expression across diverse snake tissues. We took a novel approach to studying snake venom evolution by leveraging the complete genome of the Burmese python, including information from tissue-specific patterns of gene expression. We identified the orthologs of snake venom genes in the python genome, and conducted detailed analysis of gene expression of these venom homologs to identify patterns that differ between snake venom gene families and all other genes. We found that venom gene homologs in the python are expressed in many different tissues outside of oral glands, which illustrates the pitfalls of using transcriptomic data alone to define "venom toxins." We hypothesize that the python may represent an ancestral state prior to major venom development, which is supported by our finding that the expansion of venom gene families is largely restricted to highly venomous caenophidian snakes. Therefore, the python provides insight into biases in which genes were recruited for snake venom systems. Python venom homologs are generally expressed at lower levels, have higher variance among tissues, and are expressed in fewer organs compared with all other python genes. We propose a model for the evolution of snake venoms in which venom genes are recruited preferentially from genes with particular expression profile characteristics, which facilitate a nearly neutral transition toward specialized venom system expression.


Asunto(s)
Boidae/genética , Evolución Molecular , Genómica/métodos , Venenos de Serpiente/genética , Animales , Perfilación de la Expresión Génica , Genoma , Familia de Multigenes , Especificidad de Órganos , Filogenia , Reptiles/genética , Alineación de Secuencia , Homología de Secuencia de Ácido Nucleico , Venenos de Serpiente/metabolismo
7.
Zootaxa ; 3878(4): 351-65, 2014 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-25544450

RESUMEN

The Indonesian island of Sumatra contains several endemic species of parachuting frog of the genus Rhacophorus. Most of these are known from small type series collected from only a few localities, and consequently, many Sumatran Rhacophorus species are poorly understood. Using mitochondrial DNA (mtDNA), we investigated relationships among a group of Rhacophorus species from southern Sumatra. Our molecular analysis was based on a fragment of the 16S ribosomal subunit gene (16S) and included data derived from type specimens of two species endemic to Sumatra: R. barisani and R. catamitus. Our analyses of these data reveal that the only known female specimen of R. catamitus possesses a divergent 16S sequence compared to male specimens (8.82%; uncorrected "p" distance). Based on phylogenetic reconstructions, we found that this female specimen belongs to an unnamed taxon related to R. margaritifer from Java. Consequently, we remove the specimen from R. catamitus and describe it as R. bengkuluensis sp. nov., a medium-sized slender tree frog with extensive brown hand webbing. We identified additional specimens referable to the new species using mtDNA and morphology. These specimens originate from low to intermediate elevations (ca. 600-1600 m) in the provinces of Bengkulu and Lampung, suggesting that R. bengkuluenis is widely distributed across the southwestern versant of the Bukit Barisan.


Asunto(s)
Anuros/clasificación , Anuros/genética , ADN Mitocondrial/genética , Filogenia , ARN Ribosómico 16S/genética , Distribución Animal , Animales , Anuros/crecimiento & desarrollo , Anuros/fisiología , Femenino , Indonesia , Larva/clasificación , Larva/crecimiento & desarrollo , Masculino , Especificidad de la Especie
8.
Proc Natl Acad Sci U S A ; 110(51): 20645-50, 2013 Dec 17.
Artículo en Inglés | MEDLINE | ID: mdl-24297902

RESUMEN

Snakes possess many extreme morphological and physiological adaptations. Identification of the molecular basis of these traits can provide novel understanding for vertebrate biology and medicine. Here, we study snake biology using the genome sequence of the Burmese python (Python molurus bivittatus), a model of extreme physiological and metabolic adaptation. We compare the python and king cobra genomes along with genomic samples from other snakes and perform transcriptome analysis to gain insights into the extreme phenotypes of the python. We discovered rapid and massive transcriptional responses in multiple organ systems that occur on feeding and coordinate major changes in organ size and function. Intriguingly, the homologs of these genes in humans are associated with metabolism, development, and pathology. We also found that many snake metabolic genes have undergone positive selection, which together with the rapid evolution of mitochondrial proteins, provides evidence for extensive adaptive redesign of snake metabolic pathways. Additional evidence for molecular adaptation and gene family expansions and contractions is associated with major physiological and phenotypic adaptations in snakes; genes involved are related to cell cycle, development, lungs, eyes, heart, intestine, and skeletal structure, including GRB2-associated binding protein 1, SSH, WNT16, and bone morphogenetic protein 7. Finally, changes in repetitive DNA content, guanine-cytosine isochore structure, and nucleotide substitution rates indicate major shifts in the structure and evolution of snake genomes compared with other amniotes. Phenotypic and physiological novelty in snakes seems to be driven by system-wide coordination of protein adaptation, gene expression, and changes in the structure of the genome.


Asunto(s)
Adaptación Fisiológica/fisiología , Boidae , Evolución Molecular , Regulación de la Expresión Génica/fisiología , Genoma/fisiología , Transcripción Genética/fisiología , Animales , Boidae/genética , Boidae/metabolismo , Ciclo Celular/fisiología , Humanos , Especificidad de Órganos/fisiología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...