Population size is a fundamental biological parameter that is di¤cult to estimate. By genotyping coyote (Canis latrans) faeces systematically collected in the Santa Monica Mountains near Los Angeles, California, we exemplify a general, non-invasive method to census large mammals. Four steps are involved in the estimation. First, presumed coyote faeces are collected along paths or roadways where coyotes, like most carnivores, often defaecate and mark territorial boundaries. Second, DNA is extracted from the faeces and species identity and sex is determined by mitochondrial DNA and Y-chromosome typing. Third, hypervariable microsatellite loci are typed from the faeces. Lastly, rarefaction analysis is used to estimate population size from faecal genotypes. This method readily provides a point count estimate of population size and sex ratio. Additionally, we show that home range use, paternity and kinship can be inferred from the distribution and relatedness patterns of faecal genotypes.
Summary It is known that evolution by selection on new or standing single nucleotide polymorphisms (SNPs) in the vitamin K 2,3-epoxide reductase subcomponent 1 (vkorc1) of house mice (Mus musculus domesticus) can cause resistance to anticoagulant rodenticides such as warfarin [1–3]. Here we report an introgression in European M. m. domesticus spanning as much as ~20.3 megabases (Mb) and including vkorc1, the molecular target of anticoagulants [1–4], that stems from hybridization with the Algerian mouse (M. spretus). We show that in the laboratory the homozygous complete vkorc1 allele of M. spretus confers resistance when introgressed into M. m. domesticus. Consistent with selection on the introgression after the introduction of rodenticides in the 1950s we document historically adaptive population genetics of vkorc1 in M. m. domesticus. Furthermore, we detected adaptive protein evolution of vkorc1 in the M. spretus lineage (Ka/Ks=1.54–1.93) resulting in radical amino-acid substitutions that apparently have anticoagulant tolerance of M. spretus as pleiotropic effect. Thus, positive selection produced an adaptive, divergent and pleiotropic vkorc1 allele in the donor species, M. spretus, which crossed a species barrier where it is expressed as adaptive trait in the recipient species, M. m. domesticus. Resistant house mice originated from selection on new or standing vkorc1 polymorphisms and from selection on vkorc1 polymorphisms acquired by adaptive introgressive hybridization.
We evaluate the relative effectiveness of four methods for preserving faecal samples for DNA analysis. PCR assays of fresh faecal samples collected from free-ranging baboons showed that amplification success was dependent on preservation method, PCR-product size, and whether nuclear or mitochondrial DNA was assayed. Storage in a DMSO/EDTA/Tris/salt solution (DETs) was most effective for preserving nuclear DNA, but storage in 70% ethanol, freezing at -20 degrees C and drying performed approximately equally well for mitochondrial DNA and short (< 200 bp) nuclear DNA fragments. Because faecal DNA is diluted and degraded, repeated extractions from faeces may be necessary and short nuclear markers should be employed for genotyping. A review of molecular scatology studies further suggests that three to six faeces per individual should be collected.
In the Brenta area of northern Italy, a brown bear Ursus arctos population is rapidly going extinct. Restocking of the population is planned. In order to study the genetics of this highly vulnerable population with a minimum of stress to the animals we have developed a PCR-based method that allows the study of mitochondrial and nuclear gene sequences from droppings collected in the field. This method is generally applicable to animals in the wild. Using excremental as well as hair samples, we show that the Brenta population is monomorphic for one mitochondrial lineage and that female as well as male bears exist in the area. In addition, 70 samples from other parts of Europe were studied. As others have previously reported, the mitochondrial gene pool of European bears is divided into two major clades, one with a western and the other with an eastern distribution. Whereas populations generally belong to either one or the other mitochondrial clade, the Romanian population contains both clades. The bears in the Brenta belong to the western clade. The implications for the management of brown bears in the Brenta and elsewhere in Europe are discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.