Genotyping faecal samples of Bengal tiger (Panthera tigris tigris) for population estimation: a pilot study. BMC Genet 7:48

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BMC Genetics (Impact Factor: 2.4). 02/2006; 7(1):48. DOI: 10.1186/1471-2156-7-48
Source: PubMed


Bengal tiger Panthera tigris tigris the National Animal of India, is an endangered species. Estimating populations for such species is the main objective for designing conservation measures and for evaluating those that are already in place. Due to the tiger's cryptic and secretive behaviour, it is not possible to enumerate and monitor its populations through direct observations; instead indirect methods have always been used for studying tigers in the wild. DNA methods based on non-invasive sampling have not been attempted so far for tiger population studies in India. We describe here a pilot study using DNA extracted from faecal samples of tigers for the purpose of population estimation.
In this study, PCR primers were developed based on tiger-specific variations in the mitochondrial cytochrome b for reliably identifying tiger faecal samples from those of sympatric carnivores. Microsatellite markers were developed for the identification of individual tigers with a sibling Probability of Identity of 0.005 that can distinguish even closely related individuals with 99.9% certainty. The effectiveness of using field-collected tiger faecal samples for DNA analysis was evaluated by sampling, identification and subsequently genotyping samples from two protected areas in southern India.
Our results demonstrate the feasibility of using tiger faecal matter as a potential source of DNA for population estimation of tigers in protected areas in India in addition to the methods currently in use.

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    • "PCR products were checked on an ethidium bromide-stained 1.5% agarose gel and sent for direct fragment analysis using an ABI Prism 3730xl DNA Analyzer at the University of Illinois DNA Core Sequencing Facility. Two sex chromosome genes, Zinc-finger and Amelogenin, using primers specifically designed for felids (Pilgrim et al. 2005; Bhagavatula and Singh 2006) were amplified separately using the same PCR conditions used for microsatellite loci, checked, and sent for fragment analysis. "
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    • "leo persica) (Singh et al., 2002), South China tiger (P. t. amoyensis) (Zhang et al., 2006), puma (Puma concolor) (Kurushima et al., 2006) and Bengal tiger (Bhagvatula and Singh, 2006; Sharma et al., 2008) among the Felidae. The use of species-specific microsatellites is limited by the time and expense involved and the difficulty in isolating these short tandem repeats and their flanking regions from the genomes of the target organisms. "
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    • "Most of the studies undertaken so far on the Bengal tiger (Bhagavatula and Singh 2006; Mondol et al. 2009b; Reddy et al. 2012; Sharma et al. 2013) fail to provide detailed information on locus-specific genetic characteristics (polymorphic information content [PIC] and probability of identity [P ID ]) and genotyping profile characteristics (stutter, allele to peak height etc.). Besides, information of these studies have been from fecal DNA, except for a few loci, which have been studied using high-quality DNA (Bhagavatula and Singh 2006; Mondol et al. 2009b). Thus, selection of the best loci for use in population genetics and forensic studies and minimizing genotyping errors has hitherto been precluded. "
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