189 research outputs found
Hybridization in an isolated population of blesbok and red hartebeest
Hybridization in antelope species has been widely reported in South African national parks and provincial reserves as well as on private land due to anthropogenic effects. In a closed management setting, hybridization may occur due to the crossbreeding of closely related species with unequal sex ratios, resulting in either sterile or fertile offspring. In this study, we used molecular techniques to evaluate the risk of anthropogenic hybridization between blesbok (Damaliscus pygargus phillipsi) and red hartebeest (Alcelaphus buselaphus caama) in an isolated group that purposely included the two species with unequal sex ratios (one red hartebeest male and 19 male and female blesbok). Genetic analysis based on microsatellites confirmed the presence of seven hybrid individuals. Mitochondrial analysis verified that hybridization occurred between blesbok females and the red hartebeest male. STRUCTURE and NEWHYBRIDS classified the hybrids as F1. It is suspected that the hybrid individuals were sterile as the males had undeveloped testes and only F1 hybrids were detected. Thus, the risk of hybridization between these two species may be limited in the wild. In captive settings, genetic monitoring should be included in management plans for blesbok and red hartebeest to ensure that the long-term consequences of wasted reproductive effort are limited
Diversity of selected toll-like receptor genes in cheetahs (Acinonyx jubatus) and African leopards (Panthera pardus pardus).
BackgroundThe growing world population amplifies the anthropogenic impact on wildlife globally. With shrinking habitats, wild populations are being pushed to co-exist in close proximity to humans, leading to an increased threat of infectious disease. Therefore, understanding the immune system of a species is key to assess its resilience in a changing environment. The innate immunity system (IIS) is the body’s first line of defense against pathogens. High variability in IIS-genes, such as the toll-like receptor (TLR) genes, appears to be associated with resistance to infectious diseases. However, few studies have investigated diversity in TLR genes in non-model organisms and drawn conclusions for the conservation of vulnerable species. Large predators are threatened globally, and their populations increasingly have been declining over the last decades. Big cats, such as leopards (Panthera pardus) and cheetahs (Acinonyx jubatus) are no exception to this trend and are listed as ‘vulnerable’ by the International Union for Conservation of Nature (IUCN) including several subspecies, e.g., A. j. venaticus and P. p. melas, that already face extinction. To better understand vulnerability in terms of immune genetic diversity in the two sympatric occurring species, we compared selected TLR genes (TLR2, TLR4, TLR6 and TLR8) between modern African leopards (P. p. pardus) and Southern African cheetahs (A. j. jubatus). ResultsOur study supports the previously detected high genetic diversity in African leopards and confirms genetic impoverishment in Southern African cheetahs. Despite notable differences, both species share some haplotypic similarities in the investigated TLRs. Moreover, our historic cheetah samples from all five subspecies showed levels of genetic diversity comparable to modern African leopards. By including historic cheetahs and samples from all known subspecies, we put the observed IIS diversity into an evolutionary context.ConclusionThe genetic diversity in the investigated TLR genes in modern Southern African cheetahs and in historic cheetahs is low compared to African leopards. However, according to previous studies, the low immune genetic diversity might not yet affect the health of this cheetah subspecies. Compared to historic cheetah data and other subspecies, a more recent population decline might explain the observed genetic impoverishment of TLR genes in modern Southern African cheetahs.<br/
Hybridization in an isolated population of blesbok and red hartebeest
DATA AVAILABILITY STATEMENT : All results have been deposited in Dryad (https://doi.org/10.5061/dryad.69p8cz98h).Hybridization in antelope species has been widely reported in South African national parks and provincial reserves as well as on private land due to anthropogenic effects. In a closed management setting, hybridization may occur due to the crossbreeding of closely related species with unequal sex ratios, resulting in either sterile or fertile offspring. In this study, we used molecular techniques to evaluate the risk of anthropogenic hybridization between blesbok (Damaliscus pygargus phillipsi) and red hartebeest (Alcelaphus buselaphus caama) in an isolated group that purposely included the two species with unequal sex ratios (one red hartebeest male and 19 male and female blesbok). Genetic analysis based on microsatellites confirmed the presence of seven hybrid individuals. Mitochondrial analysis verified that hybridization occurred between blesbok females and the red hartebeest male. STRUCTURE and NEWHYBRIDS classified the hybrids as F1. It is suspected that the hybrid individuals were sterile as the males had undeveloped testes and only F1 hybrids were detected. Thus, the risk of hybridization between these two species may be limited in the wild. In captive settings, genetic monitoring should be included in management plans for blesbok and red hartebeest to ensure that the long-term consequences of wasted reproductive effort are limited.http://www.ecolevol.orghj2024BiochemistryGeneticsMicrobiology and Plant PathologySDG-03:Good heatlh and well-beingSDG-15:Life on lan
Quest Volume 16 Number 3 2020
Cite: Academy of Science of South Africa (ASSAf), (2020). Quest: Science for South Africa, 16(3). [Online] Available at: http://hdl.handle.net/20.500.11911/154It’s freezing out there!: Quest explores the coldest places - Journey to the sea ice: Sejal Pramlall shares her experience in the Southern Ocean - Monitoring ice from space: Quest reports on remote sensing news - Microscopic life on the frozen continent: Don Cowan tells us about the terrestrial microbes of Antarctica - Frozen in time: a biological back-up of species: Kim Labuschagne explains how the SANBI biobank supports wildlife research
and conservation - Freezing for pollution prevention: Using phase change for cleaner effluents and emissions - Our innovation nation: Mike Bruton shares some famous inventions from South Africa - Science, technology and innovation (STI): STI Indicators Report 2020 and STI takes on COVID-19 - Traditional medicine for COVID-19: Indigenous and introduced Artemisia is in demand, but is it effective? - Inspirational young women in science: These two young scientists started their studies at the University of Zululand - Who’s who in the prehistoric zoo: Quest reports on a webinar by palaeontologist Alberto Valenciano Vaquero - Cancer genomics: Annie Joubert explains how DNA technology is changing the face of cancerDepartment of Science and Innovation; Academy of Science of South Afric
Classifying aerosol type using in situ surface spectral aerosol optical properties
Knowledge of aerosol size and composition is important
for determining radiative forcing effects of aerosols,
identifying aerosol sources and improving aerosol satellite retrieval algorithms. The ability to extrapolate aerosol size and composition, or type, from intensive aerosol optical properties can help expand the current knowledge of spatiotemporal variability in aerosol type globally, particularly where chemical composition measurements do not exist concurrently
with optical property measurements. This study
uses medians of the scattering Ångström exponent (SAE),
absorption Ångström exponent (AAE) and single scattering
albedo (SSA) from 24 stations within the NOAA/ESRL Federated
Aerosol Monitoring Network to infer aerosol type using
previously published aerosol classification schemes.
Three methods are implemented to obtain a best estimate
of dominant aerosol type at each station using aerosol optical
properties. The first method plots station medians into
an AAE vs. SAE plot space, so that a unique combination
of intensive properties corresponds with an aerosol type. The
second typing method expands on the first by introducing a
multivariate cluster analysis, which aims to group stations
with similar optical characteristics and thus similar dominant aerosol type. The third and final classification method pairs
3-day backward air mass trajectories with median aerosol optical
properties to explore the relationship between trajectory
origin (proxy for likely aerosol type) and aerosol intensive
parameters, while allowing for multiple dominant aerosol
types at each station.
The three aerosol classification methods have some common,
and thus robust, results. In general, estimating dominant
aerosol type using optical properties is best suited
for site locations with a stable and homogenous aerosol
population, particularly continental polluted (carbonaceous
aerosol), marine polluted (carbonaceous aerosol mixed with
sea salt) and continental dust/biomass sites (dust and carbonaceous
aerosol); however, current classification schemes
perform poorly when predicting dominant aerosol type at remote
marine and Arctic sites and at stations with more complex
locations and topography where variable aerosol populations
are not well represented by median optical properties.
Although the aerosol classification methods presented here
provide new ways to reduce ambiguity in typing schemes,
there is more work needed to find aerosol typing methods
that are useful for a larger range of geographic locations and
aerosol populations
Neuroendocrinology of Parental Response to Baby‐Cry
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86818/1/j.1365-2826.2011.02212.x.pd
One-carbon metabolism in cancer
Cells require one-carbon units for nucleotide synthesis, methylation and reductive metabolism, and these pathways support the high proliferative rate of cancer cells. As such, anti-folates, drugs that target one-carbon metabolism, have long been used in the treatment of cancer. Amino acids, such as serine are a major one-carbon source, and cancer cells are particularly susceptible to deprivation of one-carbon units by serine restriction or inhibition of de novo serine synthesis. Recent work has also begun to decipher the specific pathways and sub-cellular compartments that are important for one-carbon metabolism in cancer cells. In this review we summarise the historical understanding of one-carbon metabolism in cancer, describe the recent findings regarding the generation and usage of one-carbon units and explore possible future therapeutics that could exploit the dependency of cancer cells on one-carbon metabolism
High-coverage genomes to elucidate the evolution of penguins
Background: Penguins (Sphenisciformes) are a remarkable order of flightless wing-propelled diving seabirds distributed widely across the southern hemisphere. They share a volant common ancestor with Procellariiformes close to the Cretaceous-Paleogene boundary (66 million years ago) and subsequently lost the ability to fly but enhanced their diving capabilities. With ∼20 species among 6 genera, penguins range from the tropical Galápagos Islands to the oceanic temperate forests of New Zealand, the rocky coastlines of the sub-Antarctic islands, and the sea ice around Antarctica. To inhabit such diverse and extreme environments, penguins evolved many physiological and morphological adaptations. However, they are also highly sensitive to climate change. Therefore, penguins provide an exciting target system for understanding the evolutionary processes of speciation, adaptation, and demography. Genomic data are an emerging resource for addressing questions about such processes. Results: Here we present a novel dataset of 19 high-coverage genomes that, together with 2 previously published genomes, encompass all extant penguin species. We also present a well-supported phylogeny to clarify the relationships among penguins. In contrast to recent studies, our results demonstrate that the genus Aptenodytes is basal and sister to all other extant penguin genera, providing intriguing new insights into the adaptation of penguins to Antarctica. As such, our dataset provides a novel resource for understanding the evolutionary history of penguins as a clade, as well as the fine-scale relationships of individual penguin lineages. Against this background, we introduce a major consortium of international scientists dedicated to studying these genomes. Moreover, we highlight emerging issues regarding ensuring legal and respectful indigenous consultation, particularly for genomic data originating from New Zealand Taonga species. Conclusions: We believe that our dataset and project will be important for understanding evolution, increasing cultural heritage and guiding the conservation of this iconic southern hemisphere species assemblage.Fil: Pan, Hailin. Bgi-shenzhen; ChinaFil: Cole, Theresa L. University Of Otago; CanadáFil: Bi, Xupeng. Bgi-shenzhen; ChinaFil: Fang, Miaoquan. Bgi-shenzhen; ChinaFil: Zhou, Chengran. Bgi-shenzhen; ChinaFil: Yang, Zhengtao. Bgi-shenzhen; ChinaFil: Ksepka, Daniel T. Bruce Museum; Estados UnidosFil: Hart, Tom. University of Oxford; Reino UnidoFil: Bouzat, Juan L.. Bowling Green State University; Estados UnidosFil: Boersma, P. Dee. University of Washington; Estados UnidosFil: Bost, Charles-André. Centre Detudes Biologiques de Chizé; FranciaFil: Cherel, Yves. Centre Detudes Biologiques de Chizé; FranciaFil: Dann, Peter. Phillip Island Nature Parks; AustraliaFil: Mattern, Thomas. University of Otago; Nueva ZelandaFil: Ellenberg, Ursula. Global Penguin Society; Estados Unidos. La Trobe University; AustraliaFil: Garcia Borboroglu, Jorge Pablo. University of Washington; Estados Unidos. Global Penguin Society; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Argilla, Lisa S.. Otago Polytechnic; Nueva ZelandaFil: Bertelsen, Mads F.. Copenhagen Zoo; Dinamarca. University of Copenhagen; DinamarcaFil: Fiddaman, Steven R.. University of Oxford; Reino UnidoFil: Howard, Pauline. Hornby Veterinary Centre; Nueva Zelanda. South Island Wildlife Hospital; Nueva ZelandaFil: Labuschagne, Kim. National Zoological Garden; SudáfricaFil: Miller, Gary. University of Western Australia; Australia. University of Tasmania; AustraliaFil: Parker, Patricia. University of Missouri St. Louis; Estados UnidosFil: Phillips, Richard A.. Natural Environment Research Council; Reino UnidoFil: Quillfeldt, Petra. Justus-Liebig-Universit ̈ at Giessen; AlemaniaFil: Ryan, Peter G.. University of Cape Town; SudáfricaFil: Taylor, Helen. Vet Services Hawkes Bay Ltd; Nueva Zelanda. Wairoa Farm Vets; Nueva ZelandaFil: Zhang, De-Xing. Chinese Academy of Sciences; República de ChinaFil: Zhang, Guojie. BGI-Shenzhen; China. Chinese Academy of Sciences; República de China. University of Copenhagen; DinamarcaFil: McKinlay, Bruce. Department of Conservation; Nueva Zeland
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