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Manning JA, Edwards T, Clemons J, Leavitt DJ, Goldberg CS, Culver M. Scat as a source of DNA for population monitoring. Ecol Evol 2022; 12:e9415. [PMID: 36329814 PMCID: PMC9618667 DOI: 10.1002/ece3.9415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 08/22/2022] [Accepted: 09/18/2022] [Indexed: 01/26/2023] Open
Abstract
Sampling fecal droppings (scat) to genetically identify individual animals is an established method for monitoring mammal populations and could be highly useful for monitoring reptile populations. Whereas existing protocols for obtaining DNA from reptile scat focus on analyses of whole, fresh scat deposited during animal handling, the collection of scat naturally deposited by reptiles in situ, as required for non-invasive population monitoring, requires protocols to extract highly degraded DNA. Using surface swabs from such scats can reduce PCR inhibition and increase genotyping success. We report on three related but independently designed studies of DNA analyses from scat swabs of herbivorous reptiles under natural desert conditions: two free-ranging desert tortoise species (Agassiz's desert tortoise, Gopherus agassizii, California, US, and Morafka's desert tortoise, G. morafkai, Arizona, US) and the common chuckwalla (Sauromalus atar) (Arizona, US, and Sonora, MX). We analyzed samples from both tortoise species with the same set of 16 microsatellites and chuckwalla samples with four mtDNA markers; studies also varied in swab preservation medium and DNA extraction method. Microsatellite amplification success per sample, defined as ≥9 loci with amplification, was 15% for the study of Agassiz's desert tortoise and for the study of 42% Morafka's desert tortoise. For chuckwallas, we successfully amplified and sequenced 50% of samples. We recovered fragments up to 400 bp for tortoises and 980 bp for chuckwallas from scat swab samples. This study indicates that genotypes can successfully be obtained from swabs of scat from herbivorous reptiles collected in the field under natural environmental conditions and emphasizes that repeat amplifications are necessary for the genetic identification of individuals from non-invasive samples.
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Affiliation(s)
- Jeffrey A. Manning
- School of the EnvironmentWashington State UniversityPullmanWashingtonUSA
| | - Taylor Edwards
- University of Arizona Genetics Core, University of ArizonaTucsonArizonaUSA
| | - John Clemons
- School of Natural Resources and the Environment, Conservation Genetics LaboratoryUniversity of ArizonaTucsonArizonaUSA
| | - Daniel J. Leavitt
- U.S. Fish and Wildlife ServiceArizona Ecological Services Field OfficePhoenixArizonaUSA
| | - Caren S. Goldberg
- School of the EnvironmentWashington State UniversityPullmanWashingtonUSA
| | - Melanie Culver
- School of Natural Resources and the Environment, Conservation Genetics LaboratoryUniversity of ArizonaTucsonArizonaUSA,U.S. Geological Survey, Arizona Cooperative Fish and Wildlife Research UnitUniversity of ArizonaTucsonArizonaUSA
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Identifying individual ungulates from fecal DNA: a comparison of field collection methods to maximize efficiency, ease, and success. Mamm Biol 2022. [DOI: 10.1007/s42991-021-00176-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
AbstractNon-invasive genetic sampling can facilitate the identification of individual animals across a landscape, with applications to management and conservation. Fecal material is a readily available source of DNA, and various methods exist for collecting fecal samples for DNA preservation. In particular, swab methods offer considerable promise, but their utility in real-world field contexts remains relatively untested. We systematically compared multiple genetic fecal sampling methods across all stages of data collection and analysis, including sampling in the field, DNA extraction in the lab, and identification of individuals using microsatellite genotyping. We collected 112 fecal samples from black-tailed deer (Odocoileus hemionus columbianus) in the field in Mendocino County, California, across a range of sample conditions of unknown age. We systematically compared the efficiency, ease, and genotyping success of three methods for field collection and storage of ungulate fecal samples: whole pellets in ethanol, whole dry pellets in paper envelopes, and cotton swabs in buffer. Storage method, sample condition, and their interaction predicted genotyping success in the top binomial GLMMs. We found that swabbing pellets resulted in the greatest percentage of individually identifiable genotypes (81%, compared to 60% for dry samples and 56% for ethanol), despite lower DNA concentrations. While swabbing pellets requires a greater time investment in the field, the samples are easier and safer to store and transport, and subsequent labwork is more efficient as compared to whole-pellet collection methods. We, therefore, recommend the swab method for most contexts. We provide additional recommendations and field protocols based on subsequent collection of 2284 swab samples for a larger monitoring study of the deer population, given that this large number of samples spanned a range of sample conditions and time spent in storage.
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Obino Mastella AM, Rodrigues CE, Kist TBL, Ramos Pereira MJ. Take a good catch at the scat: carboxylic and sulfonic acid profiles as a non-invasive tool for species identification and sex determination in neotropical carnivores. STUDIES ON NEOTROPICAL FAUNA AND ENVIRONMENT 2021. [DOI: 10.1080/01650521.2021.1994786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Ana Maria Obino Mastella
- BiMaLab – Bird and Mammal Evolution, Systematics and Ecology Lab, Ppgban – Graduate Program in Animal Biology, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Brazil
| | - Carlos Eduardo Rodrigues
- Ppgbcm – Graduate Program in Cellular and Molecular Biology, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Brazil
- Laboratory of Methods, Department of Biophysics, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Brazil
| | - Tarso B. Ledur Kist
- Laboratory of Methods, Department of Biophysics, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Brazil
| | - Maria João Ramos Pereira
- BiMaLab – Bird and Mammal Evolution, Systematics and Ecology Lab, Ppgban – Graduate Program in Animal Biology, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Brazil
- Cesam – Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal
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Bonin M, Dussault C, Taillon J, Lecomte N, Côté SD. Combining stable isotopes, morphological, and molecular analyses to reconstruct the diet of free-ranging consumers. Ecol Evol 2020; 10:6664-6676. [PMID: 32724540 PMCID: PMC7381590 DOI: 10.1002/ece3.6397] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 04/24/2020] [Accepted: 04/30/2020] [Indexed: 02/06/2023] Open
Abstract
Accurate estimates of animal diet composition are essential to untangle complex interactions in food webs. Biomarkers and molecular tools are increasingly used to estimate diet, sometimes alongside traditional dietary tracing methods. Yet only a few empirical studies have compared the outcomes and potential gains of using a combination of these methods, especially using free-ranging animals with distinct foraging preferences.We used stable isotopes, morphological, and molecular analyses to investigate the diet of free-ranging consumers with two distinct diet types, that is, carnivore and omnivore. By combining the three analytical methods to assess the diet of consumers during the same period, we aimed to identify the limits of each method and to assess the potential benefits of their combined use to derive diet estimates.Our results showed that the different methods led to a consistent diet description for carnivores, which have a relatively simple diet mixture, but their outcomes somewhat differed for omnivore, which have a more complex diet. Still, the combined use of morphological and molecular analyses enhanced the diversity of food sources detected compared to the use of a single method independently of diet types. Precision of diet estimates derived from stable isotope analyses was improved by the addition of priors obtained from morphological and molecular diet analyses of the same population.Although we used free-ranging animals without a known diet, our empirical testing of three of the most widely used methods of diet determination highlights the limits of relying over a single approach, especially in systems with few or no a priori information about the foraging habits of consumers. The choice of an appropriate approach of diet description should be a key step when planning dietary studies of free-ranging populations. We recommend using more than one dietary determination methods especially for species with complex diet mixtures.
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Affiliation(s)
- Michaël Bonin
- Caribou UngavaCentre d’études nordiquesUniversité LavalQuébecQCCanada
| | - Christian Dussault
- Caribou UngavaCentre d’études nordiquesUniversité LavalQuébecQCCanada
- Direction de l’expertise sur la faune terrestre, l’herpétofaune et l’avifauneMinistère des Forêts, de la Faune et des ParcsQuébecQCCanada
| | - Joëlle Taillon
- Caribou UngavaCentre d’études nordiquesUniversité LavalQuébecQCCanada
- Direction de l’expertise sur la faune terrestre, l’herpétofaune et l’avifauneMinistère des Forêts, de la Faune et des ParcsQuébecQCCanada
| | - Nicolas Lecomte
- Caribou UngavaCentre d’études nordiquesUniversité LavalQuébecQCCanada
- Chaire de recherche du Canada en écologie polaire et boréaleUniversité de MonctonMonctonNBCanada
| | - Steeve D. Côté
- Caribou UngavaCentre d’études nordiquesUniversité LavalQuébecQCCanada
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Tighe AJ, Overby S, Thurman K, Gandola R, Fulanda B, Byrne J, Carlsson J. Investigating a simplified method for noninvasive genetic sampling in East African mammals using silica dried scat swabs. Ecol Evol 2020; 10:3330-3337. [PMID: 32273990 PMCID: PMC7141023 DOI: 10.1002/ece3.6115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 01/13/2020] [Accepted: 01/15/2020] [Indexed: 11/06/2022] Open
Abstract
Swabbing scat has proved to be an effective noninvasive method to collect DNA from mammals in the field. Previously, this method has relied on preservative liquids or freezing to preserve the DNA collected on swabs. In this study, we determine the effectiveness of using silica to simply dry the swab in field as an alternative way to prevent DNA degredation. Four species were included in the study; reticulated giraffe, impala, fringe-eared oryx, and lion. Swabs were taken at multiple time points for giraffe and impala scat samples, with the lion and oryx sampled opportunistically. Mitochondrial DNA was successfully amplified and sequenced from scat swabs from all species; however, effectiveness varied between species, with 81.8% amplification success rate from swabs taken from impala scat compared to 25% amplification success rate in giraffe. This variation in success rate was overcome by taking multiple swabs, thus increasing the probability of a successful amplification. The true merit of this method is in its simplicity and cheapness; no preservative liquids were required to be brought into the field, at no stage in the 2 weeks of field sampling were samples frozen, and no commercial kits were used for DNA extraction.
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Affiliation(s)
- Andrew J Tighe
- Area 52 Research Group School of Biology and Environmental Science/Earth Institute University College Dublin Dublin Ireland
- Fish Health Unit Marine Institute Oranmore Ireland
| | - Sarah Overby
- Area 52 Research Group School of Biology and Environmental Science/Earth Institute University College Dublin Dublin Ireland
- Interdisciplinary Research Structure for Biotechnology and Biomedicine (ERI BIOTECMED) University of Valencia Valencia Spain
| | - Kiera Thurman
- Area 52 Research Group School of Biology and Environmental Science/Earth Institute University College Dublin Dublin Ireland
| | - Robert Gandola
- Area 52 Research Group School of Biology and Environmental Science/Earth Institute University College Dublin Dublin Ireland
| | - Bernerd Fulanda
- Department of Biological Sciences Pwani University Kilifi Kenya
| | - John Byrne
- Area 52 Research Group School of Biology and Environmental Science/Earth Institute University College Dublin Dublin Ireland
| | - Jens Carlsson
- Area 52 Research Group School of Biology and Environmental Science/Earth Institute University College Dublin Dublin Ireland
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Bourgeois S, Kaden J, Senn H, Bunnefeld N, Jeffery KJ, Akomo-Okoue EF, Ogden R, McEwing R. Improving cost-efficiency of faecal genotyping: New tools for elephant species. PLoS One 2019; 14:e0210811. [PMID: 30699177 PMCID: PMC6353156 DOI: 10.1371/journal.pone.0210811] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 01/02/2019] [Indexed: 11/18/2022] Open
Abstract
Despite the critical need for non-invasive tools to improve monitoring of wildlife populations, especially for endangered and elusive species, faecal genetic sampling has not been adopted as regular practice, largely because of the associated technical challenges and cost. Substantial work needs to be undertaken to refine sample collection and preparation methods in order to improve sample set quality and provide cost-efficient tools that can effectively support wildlife management. In this study, we collected an extensive set of forest elephant (Loxodonta cyclotis) faecal samples throughout Gabon, Central Africa, and prepared them for genotyping using 107 single-nucleotide polymorphism assays. We developed a new quantitative polymerase chain reaction (PCR) assay targeting a 130-bp nuclear DNA fragment and demonstrated its suitability for degraded samples in all three elephant species. Using this assay to compare the efficacy of two sampling methods for faecal DNA recovery, we found that sampling the whole surface of a dung pile with a swab stored in a small tube of lysis buffer was a convenient method producing high extraction success and DNA yield. We modelled the influence of faecal quality and storage time on DNA concentration in order to provide recommendations for optimized collection and storage. The maximum storage time to ensure 75% success was two months for samples collected within 24 hours after defecation and extended to four months for samples collected within one hour. Lastly, the real-time quantitative PCR assay allowed us to predict genotyping success and pre-screen DNA samples, thus further increasing the cost-efficiency of our approach. We recommend combining the validation of an efficient sampling method, the build of in-country DNA extraction capacity for reduced storage time and the development of species-specific quantitative PCR assays in order to increase the cost-efficiency of routine non-invasive DNA analyses and expand the use of next-generation markers to non-invasive samples.
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Affiliation(s)
- Stéphanie Bourgeois
- Agence Nationale des Parcs Nationaux, Libreville, Gabon
- WildGenes Laboratory, The Royal Zoological Society of Scotland, RZSS Edinburgh Zoo, Edinburgh, United Kingdom
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, United Kingdom
- * E-mail:
| | - Jenny Kaden
- WildGenes Laboratory, The Royal Zoological Society of Scotland, RZSS Edinburgh Zoo, Edinburgh, United Kingdom
| | - Helen Senn
- WildGenes Laboratory, The Royal Zoological Society of Scotland, RZSS Edinburgh Zoo, Edinburgh, United Kingdom
| | - Nils Bunnefeld
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, United Kingdom
| | - Kathryn J. Jeffery
- Agence Nationale des Parcs Nationaux, Libreville, Gabon
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, United Kingdom
- Institut de Recherche en Écologie Tropicale, Libreville, Gabon
| | | | - Rob Ogden
- TRACE Wildlife Forensics Network, Edinburgh, United Kingdom
| | - Ross McEwing
- TRACE Wildlife Forensics Network, Edinburgh, United Kingdom
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