RESUMO
Despite decades of field study, very little is known about the molecular ecology of gibbons, particularly as it relates to their ability to disperse across degraded and fragmentary landscapes. The critically endangered western black crested gibbon (Nomascus concolor) has been reduced to a small, fragmented population with about 1300 individuals. In the largest population genetic study of free-ranging gibbons to date, we sampled 47 of these gibbons from 13 sites in China and generated 15 polymorphic autosomal microsatellite markers. We identify three population clusters of N. concolor in Yunnan centered in 1) the Wuliang and Ailao Mountains, 2) the Yongde Daxueshan Mountains, and 3) an isolated remnant near the border with Vietnam. Within the Wuliang Mountains, we identified four subclusters, three of which are bounded by high-altitude rhododendron forest, and one that is isolated from the main population by ~2 km of degraded forest and pasture. Least-cost path analysis and isolation by resistance modeling demonstrates that the population genetic distances among gibbons in Wuliangshan National Nature Reserve are significantly correlated with geographic paths that avoid use of high-altitude rhododendron forest in favor of evergreen broadleaf forest. Although these gibbons have likely undergone reductions in heterozygosity from recent consanguineous mating, we suggest that their active avoidance of inbreeding on the population level maintains higher than expected levels of genetic diversity. This research provides new insights into how gibbons interact with heterogeneous environments and expands our understanding of their molecular ecology and conservation genetics.
RESUMO
Reliable maps of species distributions are fundamental for biodiversity research and conservation. The International Union for Conservation of Nature (IUCN) range maps are widely recognized as authoritative representations of species' geographic limits, yet they might not always align with actual occurrence data. In recent area of habitat (AOH) maps, areas that are not habitat have been removed from IUCN ranges to reduce commission errors, but their concordance with actual species occurrence also remains untested. We tested concordance between occurrences recorded in camera trap surveys and predicted occurrences from the IUCN and AOH maps for 510 medium- to large-bodied mammalian species in 80 camera trap sampling areas. Across all areas, cameras detected only 39% of species expected to occur based on IUCN ranges and AOH maps; 85% of the IUCN only mismatches occurred within 200 km of range edges. Only 4% of species occurrences were detected by cameras outside IUCN ranges. The probability of mismatches between cameras and the IUCN range was significantly higher for smaller-bodied mammals and habitat specialists in the Neotropics and Indomalaya and in areas with shorter canopy forests. Our findings suggest that range and AOH maps rarely underrepresent areas where species occur, but they may more often overrepresent ranges by including areas where a species may be absent, particularly at range edges. We suggest that combining range maps with data from ground-based biodiversity sensors, such as camera traps, provides a richer knowledge base for conservation mapping and planning.
Combinación de censos con fototrampas y mapas de extensión de la UICN para incrementar el conocimiento sobre la distribución de las especies Resumen Los mapas confiables de la distribución de las especies son fundamentales para la investigación y conservación de la biodiversidad. Los mapas de distribución de la Unión Internacional para la Conservación de la Naturaleza (UICN) están reconocidos como representaciones de autoridad de los límites geográficos de las especies, aunque no siempre se alinean con los datos actuales de su presencia. En los mapas recientes de área de hábitat (ADH), las áreas que no son hábitat han sido eliminadas de la distribución de la UICN para reducir los errores de comisión, pero su concordancia con la presencia actual de las especies tampoco ha sido analizada. Analizamos la concordancia entre la presencia registrada por los censos de fototrampas y pronosticamos la presencia a partir de los mapas de la UICN y de ADH de 510 especies de mamíferos de talla mediana a grande en 80 áreas de muestreo de fototrampas. Las cámaras detectaron sólo el 39% de las especies esperadas con base en la distribución de la UICN y los mapas de ADH en todas las áreas; el 85% de las disparidades con la UICN ocurrieron dentro de los 200 km a partir del borde de la distribución. Sólo el 4% de la presencia de las especies fue detectada por las cámaras ubicadas fuera de la distribución de la UICN. La probabilidad de disparidad entre las cámaras y la UICN fue significativamente mayor para los mamíferos de talla pequeña y para los especialistas de hábitat en las regiones Neotropical e Indomalaya y en áreas con doseles forestales más bajos. Nuestros hallazgos sugieren que los mapas de distribución y ADH pocas veces subrepresentan las áreas con presencia de las especies, pero con frecuencia pueden sobrerrepresentar la distribución al incluir áreas en donde las especies pueden estar ausentes, en particular los bordes de la distribución. Sugerimos que la combinación de los mapas de distribución con los sensores de biodiversidad en tierra, como las fototrampas, proporciona una base más rica de conocimiento para el mapeo y la planeación de la conservación.
RESUMO
Multiple representatives of eulipotyphlan mammals such as shrews have oral venom systems. Venom facilitates shrews to hunt and/or hoard preys. However, little is known about their venom composition, and especially the mechanism to hoard prey in comatose states for meeting their extremely high metabolic rates. A toxin (BQTX) was identified from venomous submaxillary glands of the shrew Blarinella quadraticauda. BQTX is specifically distributed and highly concentrated (~ 1% total protein) in the organs. BQTX shares structural and functional similarities to toxins from snakes, wasps and snails, suggesting an evolutional relevancy of venoms from mammalians and non-mammalians. By potentiating thrombin and factor-XIIa and inhibiting plasmin, BQTX induces acute hypertension, blood coagulation and hypokinesia. It also shows strong analgesic function by inhibiting elastase. Notably, the toxin keeps high plasma stability with a 16-h half-life in-vivo, which likely extends intoxication to paralyze or immobilize prey hoarded fresh for later consumption and maximize foraging profit.
Assuntos
Analgesia/métodos , Hipocinesia/fisiopatologia , Musaranhos/metabolismo , Toxinas Biológicas/metabolismo , Peçonhas/metabolismo , Adulto , Sequência de Aminoácidos , Animais , Sequência de Bases , Pressão Sanguínea/efeitos dos fármacos , Feminino , Membro Posterior/efeitos dos fármacos , Membro Posterior/fisiopatologia , Humanos , Macaca mulatta , Masculino , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Dor/induzido quimicamente , Dor/fisiopatologia , Dor/prevenção & controle , Homologia de Sequência de Aminoácidos , Musaranhos/genética , Trombina/antagonistas & inibidores , Trombina/metabolismo , Toxinas Biológicas/administração & dosagem , Toxinas Biológicas/genética , Peçonhas/genéticaRESUMO
For organisms to survive and prosper in a harsh environment, particularly under rapid climate change, poses tremendous challenges. Recent studies have highlighted the continued loss of megafauna in terrestrial ecosystems and the subsequent surge of small mammals, such as rodents, bats, lagomorphs, and insectivores. However, the ecological partitioning of these animals will likely lead to large variation in their responses to environmental change. In the present study, we investigated the evolutionary history and genetic adaptations of white-bellied rats (Niviventer Marshall, 1976), which are widespread in the natural terrestrial ecosystems in Asia but also known as important zoonotic pathogen vectors and transmitters. The southeastern Qinghai-Tibet Plateau was inferred as the origin center of this genus, with parallel diversification in temperate and tropical niches. Demographic history analyses from mitochondrial and nuclear sequences of Niviventer demonstrated population size increases and range expansion for species in Southeast Asia, and habitat generalists elsewhere. Unexpectedly, population increases were seen in N. eha, which inhabits the highest elevation among Niviventer species. Genome scans of nuclear exons revealed that among the congeneric species, N. eha has the largest number of positively selected genes. Protein functions of these genes are mainly related to olfaction, taste, and tumor suppression. Extensive genetic modification presents a major strategy in response to global changes in these alpine species.
Assuntos
Distribuição Animal , Mudança Climática , Especiação Genética , Murinae/genética , Filogenia , Altitude , Animais , Clima , Filogeografia , Seleção GenéticaRESUMO
The striped-back shrew group demonstrates remarkable variation in skull and body size, tail length, and brightness of the dorsal stripe; and karyotypic and DNA variation has been reported in recent years. In this study, we investigated the phylogenetic structure of the group, as well as speciation patterns and demographic history in Mountains of Southwestern China and adjacent mountains, including the southern Himalayas, Mts. Bashan, Wushan, and Qinling. We sequenced a total of 462 specimens from 126 localities in the known range of the group, which were sequenced and analyzed based on 6.2 kb of sequence data from two mitochondrial, six nuclear, and two Y chromosome markers. Phylogenetic analyses of the concatenated mtDNA data revealed 14 sympatric and independently evolving lineages within the striped-back shrew group, including Sorex bedfordiae, S. cylindricauda, S. excelsus, S. sinalis and several cryptic species. All concatenated data (ten genes) showed a consistent genetic structure compared to the mtDNA lineages for the group, whereas the nuclear and the Y chromosome data showed a discordant genetic structure compared to the mtDNA lineages for the striped-back shrew group. Species delimitation analyses and deep genetic distance clearly support the species status of the 14 evolving lineages. The divergence time estimation suggested that the striped-back shrew group began to diversify from the middle Pleistocene (2.34 Ma), then flourished at approximately 2.14 Ma, followed by a series of rapid diversifications through the Pleistocene. Our results also revealed multiple mechanisms of speciation in the Mountains of Southwestern China and Adjacent Mountains with complex landscapes and climate. The uplifting of the Qinghai-Tibetan Plateau, Quaternary climate oscillations, riverine barriers, ecological elevation gradients, topographical diversity, and their own low dispersal capacity may have driven the speciation, genetic structure, and phylogeographic patterns of the striped-back shrew group.
Assuntos
Eulipotyphla , Musaranhos , Animais , DNA Mitocondrial/genética , Marcadores Genéticos , Variação Genética , Filogenia , Musaranhos/genéticaRESUMO
In the Anthropocene, understanding the impacts of anthropogenic influence on biodiversity and behavior of vulnerable wildlife communities is increasingly relevant to effective conservation. However, comparative studies aimed at disentangling the concurrent effect of different types of human disturbance on multifaceted biodiversity and on activity patterns of mammals are surprisingly rare. We applied a multiregion community model to separately estimate the effects of cumulative human modification (e.g., settlement, agriculture, and transportation) and human presence (aggregated presence of dogs, people, and livestock) on species richness and functional composition of medium- and large-bodied mammals based on camera trap data collected across 45 subtropical montane forests. We divided the detected mammal species into three trophic guilds-carnivores, herbivores, and omnivores-and assessed the nocturnal shifts of each guild in response to anthropogenic activities. Overall, species richness tended to increase (ß coefficient = 0.954) as human modification increased but richness decreased as human presence increased (ß = -1.054). Human modification was associated with significantly lower functional diversity (mean nearest taxon distance [MNTD], ß = -0.134; standardized effect sizes of MNTD, ß = -0.397), community average body mass (ß = -0.240), and proportion of carnivores (ß = -0.580). Human presence was associated with a strongly reduced proportion of herbivores (ß = -0.522), whereas proportion of omnivores significantly increased as human presence (ß = 0.378) and habitat modification (ß = 0.419) increased. In terms of activity patterns, omnivores (ß = 12.103) and carnivores (ß = 9.368) became more nocturnal in response to human modification. Our results suggest that human modification and human presence have differing effects on mammals and demonstrate that anthropogenic disturbances can lead to drastic loss of functional diversity and result in a shift to nocturnal behavior of mammals. Conservation planning should consider concurrent effects of different types of human disturbance on species richness, functional diversity, and behavior of wildlife communities.
Pérdidas en la Diversidad Funcional y Cambios en el Comportamiento Nocturno de los Mamíferos bajo la Perturbación Antropogénica Resumen En el Antropoceno, el conocimiento sobre la influencia antropogénica sobre la biodiversidad y el comportamiento de las comunidades vulnerables de fauna es cada vez más relevante para la conservación efectiva. Sin embargo, sorprende que los estudios comparativos dirigidos a desentrañar el efecto concurrente de los diferentes tipos de perturbación humana sobre la biodiversidad multifacética y sobre los patrones de actividad de los mamíferos son escasos. Aplicamos un modelo de comunidad multirregional para estimar de manera separada los efectos de la modificación humana (p. ej.: establecimientos, agricultura, transporte) y la presencia humana (presencia agregada de perros, gente y ganado) acumuladas sobre la riqueza de especies y la composición funcional de los mamíferos de tamaño mediano y grande con base en datos de fototrampas recolectados en 45 bosques montanos subtropicales. Dividimos las especies de mamíferos detectadas en tres gremios tróficos: carnívoros, herbívoros y omnívoros, y analizamos los cambios nocturnos de cada gremio como respuesta a las actividades antropogénicas. En general, la riqueza de especies tuvo una tendencia al incremento (coeficiente ß = 0.954) conforme aumentaron las modificaciones humanas, pero la riqueza disminuyó conforme incrementó la presencia humana (ß = −1.054). Las modificaciones humanas estuvieron asociadas con una diversidad funcional (distancia promedio al taxón más cercano [DPTC], ß = −0.134; tamaños del efecto estandarizado de la DPTC, ß = −0.397), masa corporal promedio de la comunidad (ß = −0.240) y proporción de carnívoros (ß = −0.580) significativamente más bajas. La presencia humana estuvo asociada con una proporción gravemente reducida de herbívoros (ß = −0.522), mientras que la proporción de omnívoros incrementó significativamente conforme aumentaron la presencia humana (ß = 0.378) y la modificación del hábitat (ß = 0.419). En cuanto a los patrones de actividad, los omnívoros (ß = 12.103) y los carnívoros (ß = 9.368) se volvieron más nocturnos como respuesta a las modificaciones humanas. Nuestros resultados sugieren que las modificaciones humanas y la presencia de personas tienen efectos diferentes sobre los mamíferos y demuestran que las perturbaciones antropogénicas pueden llevar a pérdidas drásticas de la diversidad funcional y resultar en un cambio hacia el comportamiento nocturno en los mamíferos. La planeación de la conservación debería considerar los efectos concurrentes de los diferentes tipos de perturbaciones humanas sobre la riqueza de especies, la diversidad funcional y el comportamiento de las comunidades faunísticas.
Assuntos
Efeitos Antropogênicos , Conservação dos Recursos Naturais , Animais , Animais Selvagens , Biodiversidade , Conservação dos Recursos Naturais/métodos , Cães , Ecossistema , Humanos , Mamíferos/fisiologiaRESUMO
Adult males living in a one-male multi-female social group are expected to try to monopolize copulations with resident females to increase reproductive fitness. Gibbons have traditionally been described as living in monogamous groups, with the sole resident adult male assumed to sire all of the group's offspring. Here, we used microsatellite analyses and behavioral observations to examine rates of extra-group paternity (EGP) over 16 years in a population of crested gibbons (Nomascus concolor) that form stable and long-term one-male two-female social units. Forty percent of offspring (N = 14) were sired by extra-group males. To understand this high level of EGP, we tested whether inbreeding avoidance was related to EGP. Females who engaged in EGP did not show larger pairwise relatedness with their resident male compared to females who did not engage in EGP. Nevertheless, the standardized heterozygosity of EGP offspring was significantly higher than for offspring sired by the group's resident male. These results provide partial support for the inbreeding avoidance hypothesis. It appears that resident male crested gibbons are unable to monopolize resident females' matings. Our results indicate that long-term social partners are often distinct from sexual partners in this population. Clearly, the breeding system of crested gibbons is more flexible than previously thought, indicating a need for integrating long-term behavioral data and genetic research to re-evaluate gibbon social and sexual relationships derived from concepts of monogamy and pair-bonding.
Assuntos
Hylobates , Comportamento Sexual Animal , Animais , Feminino , Humanos , Endogamia , Masculino , Reprodução , Parceiros SexuaisRESUMO
The mountains of southwest China (MSWC) is a biodiversity hotspot with highly complex and unusual terrain. However, with the majority of studies focusing on the biogeographic consequences of massive mountain building, the Quaternary legacy of biodiversity for the MSWC has long been overlooked. Here, we took a statistical comparative phylogeography approach to examine factors that shaped community-wide diversification. With data from 30 vertebrate species, the results reveal spatially concordant genetic structure, and temporally clustered co-divergence events associated with river barriers during severe glacial cycles. This indicates the importance of riverine barriers in the phylogeographic history of the MSWC vertebrate community. We conclude that the repeated glacial cycles are associated with co-divergences that are themselves structured by the heterogeneity of the montane landscape of the MSWC. This orderly process of diversification has profound implications for conservation by highlighting the relative independence of different geographical areas in which some, but not all species in communities have responded similarly to climate change and calls for further comparative phylogeographic investigations to reveal the connection between biological traits and divergence pulses in this biodiversity hotspot.
Assuntos
Biodiversidade , Mudança Climática , China , Variação Genética , Filogenia , FilogeografiaRESUMO
BACKGROUND: Crocidura, the most speciose mammalian genus, occurs across much of Asia, Europe and Africa. The taxonomy of Chinese representatives has been studied primarily based on cursory morphological comparisons and their molecular phylogenetic analyses remain unexplored. In order to understand the phylogeny of this group in China, we estimated the first multilocus phylogeny and conducted species delimitation, including taxon sampling throughout their distribution range. RESULTS: We obtained one mitochondrial gene (cytb) (~ 1, 134 bp) and three nuclear genes (ApoB, BRCA1, RAG1) (~ 2, 170 bp) for 132 samples from 57 localities. Molecular analyses identified at least 14 putative species that occur within two major well-supported groups in China. Polyphyletic C. wuchihensis appears to be composed of two putative species. Two subspecies, C. rapax rapax and C. rapax kurodai should be elevated to full species status. A phylogenetic tree based on mitochondrial gene from Asian Crocidura species showed that the C. rapax rapax is embedded within C. attenuata, making the latter a paraphyletic group. Three strongly supported undescribed species (C. sp.1, C. sp.2 and C. sp.3) are revealed from Zada County of Tibet (Western China), Hongjiang County of Hunan Province (Central China) and Dongyang County of Zhejiang Province (Eastern China), Motuo County of Tibet, respectively. The divergence time estimation suggested that China's Crocidura species began to diversify during the late Pliocene (3.66 Ma) and the Early Pleistocene (2.29 Ma), followed by a series of diversifications through the Pleistocene. CONCLUSIONS: The cryptic diversity found in this study indicated that the number of species is strongly underestimated under the current taxonomy. We propose that the three undescribed species should be evaluated using extensive taxon sampling and comprehensive morphological and morphometric approaches. Climate change since the late Pliocene and the uplift of the Qinghai-Tibet Plateau may result in the diversification and speciation of China's Crocidura species. In short, the underestimated diversity underlines the need for a taxonomic revision of Chinese Crocidura species.
Assuntos
Variação Genética , Musaranhos/classificação , Musaranhos/genética , África , Animais , Ásia , China , DNA Mitocondrial/genética , Europa (Continente) , Genes Mitocondriais , Tipagem de Sequências Multilocus/métodos , Tipagem de Sequências Multilocus/veterinária , Filogenia , Filogeografia , TibetRESUMO
Food abundance and climatic factors can significantly affect the behavior of animals and constrain their activity budgets. The population of western black crested gibbons (Nomascus concolor) in Mt. Wuliang lives in montane forest and is close to the northern extreme of the distribution for gibbons (Hylobatidae). Their habitats show remarkable seasonal variation in terms of food availability, temperature, and rainfall. To understand behavioral adaptations of western black crested gibbons to different sets of ecological conditions, we examined relationships among food availability, mean temperature, rainfall, and behavior patterns by observing two groups for 1 year each. Our results revealed that activity budget was affected by food availability and mean temperature. The gibbons spent more time eating flowers when that resource was more available and spent less time moving when fruit was more available. The gibbons spent less time feeding and more time resting, and spent less feeding time on fruit and leaves when the mean temperature was lower. These results suggest that the gibbons displayed a pronounced preference for flowers as a food resource and adopted a time minimizer strategy when high-nutrient food items (i.e., fruit) were more available. In addition, the gibbons adopted an energy-conserving strategy during periods of low temperature. The flexibility of behavioral patterns in responding to food availability and temperature may potentially improve the gibbons' prospects of surviving and reproducing in a northern montane forest.
Assuntos
Temperatura Baixa , Dieta/veterinária , Comportamento Alimentar , Temperatura Alta , Hylobatidae/fisiologia , Animais , China , Feminino , Masculino , Nutrientes/análise , Fatores de TempoRESUMO
BACKGROUND: Past climatological events and contemporary geophysical barriers shape the distribution, population genetic structure, and evolutionary history of many organisms. The Himalayan region, frequently referred to as the third pole of the Earth, has experienced large-scale climatic oscillations in the past and bears unique geographic, topographic, and climatic areas. The influences of the Pleistocene climatic fluctuations and present-day geographical barriers such as rivers in shaping the demographic history and population genetic structure of organisms in the Nepal Himalaya have not yet been documented. Hence, we examined the effects of late-Quaternary glacial-interglacial cycles and riverine barriers on the genetic composition of Hanuman langurs (Semnopithecus entellus), a colobine primate with a wide range of altitudinal distribution across the Nepalese Himalaya, using the mitochondrial DNA control region (CR, 1090 bp) and cytochrome B (CYTB, 1140 bp) sequences combined with paleodistribution modeling. RESULTS: DNA sequences were successfully retrieved from 67 non-invasively collected fecal samples belonging to 18 wild Hanuman langur troops covering the entire distribution range of the species in Nepal. We identified 37 haplotypes from the concatenated CR + CYTB (2230 bp) sequences, with haplotype and nucleotide diversities of 0.958 ± 0.015 and 0.0237 ± 0.0008, respectively. The troops were clustered into six major clades corresponding to their river-isolated spatial distribution, with the significantly high genetic variation among these clades confirming the barrier effects of the snow-fed Himalayan rivers on genetic structuring. Analysis of demographic history projected a decrease in population size with the onset of the last glacial maximum (LGM); and, in accordance with the molecular analyses, paleodistribution modeling revealed a range shift in its suitable habitat downward/southward during the LGM. The complex genetic structure among the populations of central Nepal, and the stable optimal habitat through the last interglacial period to the present suggest that the central mid-hills of Nepal served as glacial refugia for the Hanuman langur. CONCLUSIONS: Hanuman langurs of the Nepal Himalaya region exhibit high genetic diversity, with their population genetic structure is strongly shaped by riverine barrier effects beyond isolation by distance; hence, this species demands detailed future phylogenetic study.
Assuntos
Colobinae/genética , Ecossistema , Genética Populacional , Rios , Animais , Sequência de Bases , Teorema de Bayes , Estruturas Genéticas , Geografia , Haplótipos/genética , Modelos Teóricos , Nepal , Paleontologia , Filogenia , Polimorfismo GenéticoRESUMO
The mammalian family Talpidae (moles, shrew moles, desmans) is characterized by diverse ecomorphologies associated with terrestrial, semi-aquatic, semi-fossorial, fossorial, and aquatic-fossorial lifestyles. Prominent specializations involved with these different lifestyles, and the transitions between them, pose outstanding questions regarding the evolutionary history within the family, not only for living but also for fossil taxa. Here, we investigate the phylogenetic relationships, divergence times, and biogeographic history of the family using 19 nuclear and 2 mitochondrial genes (â¼16 kb) from â¼60% of described species representing all 17 genera. Our phylogenetic analyses help settle classical questions in the evolution of moles, identify an ancient (mid-Miocene) split within the monotypic genus Scaptonyx, and indicate that talpid species richness may be nearly 30% higher than previously recognized. Our results also uniformly support the monophyly of long-tailed moles with the two shrew mole tribes and confirm that the Gansu mole is the sole living Asian member of an otherwise North American radiation. Finally, we provide evidence that aquatic specializations within the tribes Condylurini and Desmanini evolved along different morphological trajectories, though we were unable to statistically reject monophyly of the strictly fossorial tribes Talpini and Scalopini.
Assuntos
Toupeiras/genética , Musaranhos/genética , Animais , Evolução Biológica , Classificação/métodos , Bases de Dados de Ácidos Nucleicos , Variação Genética , Filogenia , Análise de Sequência de DNA/métodos , Especificidade da EspécieRESUMO
Gibbons are generally reported to live in small socially monogamous family groups in which both sexes disperse when they reach maturity. For the first time, we documented the dispersal pattern in a population of gibbons living in stable polygynous groups (Nomascus concolor) integrating 16 years' field observation and genetic information from fecal DNA. All subadult males except for one dispersed at 9.8 ± 1.4 years of age (range: 8-12, N = 10). The last male remained in his natal group and obtained the breeding position at age 11 by evicting the original dominant male. Females reached sexual maturity (as evidenced by the change in body color from black to yellow) at 8 years (N = 4). Three of them dispersed and one obtained a position as a breeding female and bred in her natal group. We also observed one female returning to her natal group with her infant after her presumed father was taken over by a neighboring male. We identified only three mtDNA haplotypes from 22 individuals at Dazhaizi. Individuals in one group shared the same haplotype, with only one exception. Genetic results showed that the two breeding females were mother-daughter pairs in all three study groups at the end of this study, implying some degree of female philopatry. We argue that in the case of black crested gibbons, dispersal decisions appear to represent highly opportunistic events in response to reproductive opportunities in their natal and neighboring groups.
Assuntos
Distribuição Animal , Hylobatidae/fisiologia , Animais , China , Feminino , Hylobatidae/genética , Masculino , Comportamento Sexual AnimalRESUMO
Genetic diversity of a species is influenced by multiple factors, including the Quaternary glacial-interglacial cycles and geophysical barriers. Such factors are not yet well documented for fauna from the southern border of the Himalayan region. This study used mitochondrial DNA (mtDNA) sequences and ecological niche modeling (ENM) to explore how the late Pleistocene climatic fluctuations and complex geography of the Himalayan region have shaped genetic diversity, population genetic structure, and demographic history of the Nepalese population of Assam macaques (Macaca assamensis) in the Himalayan foothills. A total of 277 fecal samples were collected from 39 wild troops over almost the entire distribution of the species in Nepal. The mtDNA fragment encompassing the complete control region (1121 bp) was recovered from 208 samples, thus defining 54 haplotypes. Results showed low nucleotide diversity (0.0075 ± SD 0.0001) but high haplotype diversity (0.965 ± SD 0.004). The mtDNA sequences revealed a shallow population genetic structure with a moderate but statistically significant effect of isolation by distance. Demographic history analyses using mtDNA sequences suggested a post-pleistocene population expansion. Paleodistribution reconstruction projected that the potential habitat of the Assam macaque was confined to the lower elevations of central Nepal during the Last Glacial Maximum. With the onset of the Holocene climatic optimum, the glacial refugia population experienced eastward range expansion to higher elevations. We conclude that the low genetic diversity and shallow population genetic structure of the Assam macaque population in the Nepal Himalaya region are the consequence of recent demographic and spatial expansion.
Assuntos
Distribuição Animal , Mudança Climática , DNA Mitocondrial/análise , Ecossistema , Variação Genética , Macaca/fisiologia , Animais , Fezes/química , Haplótipos , Macaca/genética , Modelos Biológicos , NepalRESUMO
The phylogeny of living pikas (Ochotonidae, Ochotona) remains obscure, and pika species diversity in southwestern China has never been well explored. In this study, 96 tissue samples from 11 valid species in three classified subgenera (Pika, Ochotona and Conothoa) from 23 locations were characterized using multilocus sequences of 7031bp. Two mitochondrial (CYT B and COI) and five nuclear gene segments (RAG1, RAG2, TTN, OXAIL and IL1RAPL1) were sequenced. We analysed evolutionary histories using maximum likelihood (RAxML) and Bayesian analyses (BEAST), and we also used molecular species delimitation analyses (BPP) to explore species diversity. Our study supported O. syrinx (O. huangensis) as a distinct clade from all named subgenera. Relationships among subgenera were not fully resolved, which may be due to a rapid diversification in the middle Miocene (â¼13.90Ma). Conflicting gene trees implied mitochondrial introgression from O. cansus to O. curzoniae. We uncovered three cryptic species from Shaanxi, Sichuan and Yunnan with strong support, suggesting an underestimation of species diversity in the "sky-island" mountains of southwest China.
Assuntos
Fluxo Gênico , Loci Gênicos , Variação Genética , Lagomorpha/classificação , Lagomorpha/genética , Animais , Sequência de Bases , Teorema de Bayes , China , Geografia , Filogenia , Especificidade da EspécieRESUMO
We describe a species of Hoolock gibbon (Primates: Hylobatidae) that is new to science from eastern Myanmar and southwestern China. The genus of hoolock gibbons comprises two previously described living species, the western (Hoolock hoolock) and eastern hoolock (H. leuconedys) gibbons, geographically isolated by the Chindwin River. We assessed the morphological and genetic characteristics of wild animals and museum specimens, and conducted multi-disciplinary analyses using mitochondrial genomic sequences, external morphology, and craniodental characters to evaluate the taxonomic status of the hoolock population in China. The results suggest that hoolocks distributed to the east of the Irrawaddy-Nmai Hka Rivers, which were previously assigned to H. leuconedys, are morphologically and genetically distinct from those to the west of the river, and should be recognized as a new species, the Gaoligong hoolock gibbon or skywalker hoolock gibbon (H. tianxing sp. nov.). We consider that the new species should be categorized as Endangered under IUCN criteria. The discovery of the new species focuses attention on the need for improved conservation of small apes, many of which are in danger of extinction in southern China and Southeast Asia.
Assuntos
Distribuição Animal , Hylobatidae/classificação , Animais , China , Citocromos b/genética , Hylobatidae/anatomia & histologia , Hylobatidae/genética , Filogenia , Análise de Sequência de DNA , Especificidade da EspécieRESUMO
BACKGROUND: Niviventer is a genus of white-bellied rats that are among the most common rodents in the Indo-Sundaic region. The taxonomy of the genus has undergone extensive revisions and remains controversial. The current phylogeny is unresolved and was developed primarily on the basis of mitochondrial genes. Identification is extremely difficult, and a large number of GenBank sequences seem to be problematic. We extensively sampled specimens of Niviventer in China and neighboring northern Vietnam, including topotypes of the most reported species (n = 6), subspecies (n = 8), and synonyms (n = 4). We estimated phylogenetic relationships on the basis of one mitochondrial and three nuclear genes, using concatenation and coalescent-based approaches. We also employed molecular species delimitation approaches to test the existence of cryptic and putative new species. RESULTS: Our phylogeny was finely resolved, especially for the N. confucianus-like species. Our data provided the first support for N. brahma and N. eha as sister species, an assignment that is congruent with their morphological similarities. Species delimitation analyses provided new insight into species diversity and systematics. Three geographic populations of N. confucianus and one of N. fulvescens were supported as genetically distinct in our species delimitation analyses, while three recognized species (N. coninga, N. huang, and N. lotipes) were not strongly supported as distinct. CONCLUSIONS: Our results suggested that several genetically distinct species may be contained within the species currently known as N. confucianus and N. fulvescens. In addition, the results of Bayesian Phylogenetics and Phylogeography (BPP) for N. coninga, N. huang, and N. lotipes indicated that either inter-specific gene flow had occurred or imperfect taxonomy was present. Morphological examinations and morphometric analyses are warranted to examine the molecular results.
Assuntos
Murinae/genética , Animais , Teorema de Bayes , China , DNA Mitocondrial/genética , Genes Mitocondriais , Mitocôndrias/genética , Murinae/classificação , Filogenia , FilogeografiaRESUMO
The southeastern margin of the Tibetan Plateau is characterized by complex topography and a discontinuous landscape, creating a sky island situation. However, the way topography shapes genetic structures and demographic histories of endemic species has not been well studied. We examined the phylogeographic pattern and demographic histories of Sorex bedfordiae, a dispersal-limited small mammal, using three nuclear genes [1977bp] and two mitochondrial genes [1794bp] with comprehensive molecular approaches. We recovered five well-supported clades whose distributions are along mountain ridges and roughly subdivided by large rivers. Demographic expansions in the middle Pleistocene were strongly supported by both nuclear and mitochondrial genes. Our results support the hypothesis that sky island topography and river systems strongly affect the genetic structure of non-aquatic terrestrial species. We further clarify that S. bedfordiae and S. cylindricauda are valid sibling species, whereas S. excelsus is most likely a geographic subspecies of S. bedfordiae.
Assuntos
Evolução Biológica , Eulipotyphla/classificação , Filogenia , Animais , Teorema de Bayes , Núcleo Celular/genética , DNA Mitocondrial/genética , Variação Genética , Geografia , Haplótipos , Modelos Genéticos , Filogeografia , Análise de Sequência de DNA , TibetRESUMO
Hibernating mammals need to be insensitive to acid in order to cope with conditions of high CO2; however, the molecular basis of acid tolerance remains largely unknown. The African naked mole-rat (Heterocephalus glaber) and hibernating mammals share similar environments and physiological features. In the naked mole-rat, acid insensitivity has been shown to be conferred by the functional motif of the sodium ion channel NaV1.7. There is now an opportunity to evaluate acid insensitivity in other taxa. In this study, we tested for functional convergence of NaV1.7 in 71 species of mammals, including 22 species that hibernate. Our analyses revealed a functional convergence of amino acid sequences, which occurred at least six times independently in mammals that hibernate. Evolutionary analyses determined that the convergence results from both parallel and divergent evolution of residues in the functional motif. Our findings not only identify the functional molecules responsible for acid insensitivity in hibernating mammals, but also open new avenues to elucidate the molecular underpinnings of acid insensitivity in mammals.
Assuntos
Ácidos/metabolismo , Adaptação Biológica/fisiologia , Evolução Molecular , Hibernação/fisiologia , Mamíferos/fisiologia , Modelos Moleculares , Canal de Sódio Disparado por Voltagem NAV1.7/metabolismo , Sequência de Aminoácidos/genética , Animais , Sequência de Bases , Dados de Sequência Molecular , Canal de Sódio Disparado por Voltagem NAV1.7/genética , Filogenia , Conformação Proteica , Análise de Sequência de DNA , Especificidade da EspécieRESUMO
The tribe Talpini is a group of strictly subterranean moles distributed across the Eurasian Continent whose phylogenetic relationships and taxonomy remain unresolved. Here we report a multi-locus nuclear-mitochondrial DNA dataset (9468 bp) from 11 talpine species encompassing all five recognized genera, together with analyses of their divergence times and evolutionary affinities inferred from maximum likelihood and Bayesian approaches. Our results finely resolved all relationships except the root of the four recognized Asian genera, which was placed sister to the genus Talpa. With respect to the Asian clade, we moreover provide the first molecular support for a sister-taxon relationship between Parascaptor and Scaptochirus and confirm that the genus Euroscaptor is paraphyletic. Further, and despite a relatively small sample size (22 specimens), our species delimitation analyses support the existence of at least two genetically distinct, and hence potentially cryptic species. Taken together, these findings argue that generic status should be given to E. mizura and illustrate that the taxonomic diversity of the tribe Talpini in mountainous regions of southwestern China and Southeast Asia is underestimated. Finally, results of our divergence time analyses support a rapid radiation of the endemic Asian genera in the late-Miocene, which temporally corresponds with enhanced aridity and cooling arising from a significant uplift of the Himalayan-Tibetan plateau.