Ready on arrival: Standing variation at a chromosomal inversion contributes to rapid adaptation in an invasive marine crab.

In this issue of Molecular Ecology, Tepolt et al. (2021) illustrate how the genetic architecture of adaptation and life history influence invasive success. A marvel of many invasive species is that they are incredibly successful despite evolutionary expectations that they will have low adaptive potential and suffer inbreeding depression due to initially small founding population sizes. Determining the combinations of ecoevolutionary factors that permit this apparent "genetic paradox of invasions" is an ongoing endeavour of invasive species research. Tepolt et al. (2021) study the European green crab in its invasive range on the North American west coast. Following a single introduction into California, this crab quickly spread across a wide latitude gradient, despite low diversity in the original founding population. Adaptation of this crab to clinal variation in temperature appeared largely driven by an inferred chromosomal inversion. This inversion exists as a balanced polymorphism in the European home range of green crabs and is associated with thermal tolerance. Tepolt et al. (2021) therefore demonstrate that adaptive evolution post introduction need not be impeded by bottlenecks if variation at key parts of the genome is available and can be maintained in introduced populations. Moreover, Tepolt et al. (2021) show how chromosomal inversions acting as large-effect loci might facilitate rapid responses to selection in introduced populations.

Population genetic attributes of common leopard (Panthera pardus fusca) from Uttarkashi, Western Himalayas.

BACKGROUND: The common leopard (Panthera pardus fusca), which persists in most of its historic range, is experiencing steady population decline due to habitat loss, anthrophonic disturbances, illegal poaching for their body parts, and retaliatory killings in response to the leopard-human conflicts. METHODS AND RESULTS: We analysed 143 scats samples and identified 32 unique leopards following a selected panel of seven loci with cumulative PID sibs 5.30E-04. We observed moderate genetic diversity at nuclear (Ho = 0.600 ± 0.06) and mitochondrial markers (Hd = 0.569 ± 0.009; π = 0.001 ± 0.0002) and found sub-structuring in the leopard population at Uttarkashi, Western Himalayas. CONCLUSIONS: The present study exhibits the utility of non-invasive genetics in monitoring the leopard population and paves the path to investigate population genetic parameters in further studies.

Population genetics of Sambar (Rusa unicolor) from the Western Himalayas: preliminary findings.

BACKGROUND: The sambar (Rusa unicolor) is one of the largest deer distributed across diverse habitats of India and threatened due to habitat loss, changes in the land-use patterns, illegal poaching, and anthropogenic disturbances. Here, we report the first population genetics account of sambar deer from the Western Himalayas. METHODS AND RESULTS: We observed relatively compromised genetic diversity (π = 0.0008 ± 0.0006 at mtDNA and Ho = 0.499 ± 0.056 at nDNA). We identified 60 unique individuals using a select panel of seven loci (PID sib cum 1.60E-03). Bayesian skyline plot showed a stable demographic history since the past 8 kyr with a decline in recent years. The population lacked genetic structuring, likely due to the contiguous distribution and large dispersal patterns of sambar. CONCLUSION: The preliminary findings are valuable in exploring the utility of genetic diversity in monitoring the sambar population, estimating density following capture-recapture analysis, and aid to the conservation planning of sambar in large landscapes.

Genetic monitoring of Himalayan goral (Naemorhedus goral) from Western Himalayas, India.

BACKGROUND: Himalayan goral (Naemorhedus goral), solitary cliff-dwelling species and are distributed throughout the Indian Himalayan region. Its populations across the range are facing severe threats due to habitat loss, fragmentation and changes in the land-use patterns by various anthropogenic activities. METHODS AND RESULTS: We carried out genetic analyses of Himalayan goral using the mitochondrial control regions and microsatellite loci (n = 10) in the Uttarkashi district of Uttarakhand. We reported a moderate genetic diversity at nuclear (Ho 0.602 ± 0.057) and mitochondrial markers (Hd-0.6931 ± 0.053; π-0.0048 ± 001). Bayesian skyline plot indicates a sharp decline in the goral population in the last 100 years. CONCLUSIONS: Our results indicate the population of Himalayan goral in Uttarkashi is under panmictic condition, plausibly due to long-ranging behaviour. The present study laid the foundation for future non-invasive genetics monitoring and detailed population genetic assessment of goral from the entire range in the Western Himalayas.

Gastrointestinal parasites of the New England cottontail rabbit (Sylvilagus transitionalis) and eastern cottontail rabbit (Sylvilagus floridanus) in the Hudson Valley, New York.

The New England cottontail rabbit (NEC, Sylvilagus transitionalis) population has decreased dramatically in New York, USA, and the role of parasites in limiting the population has never been examined. The closely related and sympatric eastern cottontail rabbit (EC, Sylvilagus floridanus) was introduced into the range of NEC by humans and is currently thriving. This study aimed to investigate gastrointestinal parasites of the NEC and the EC and compare their parasite communities. Fecal pellets from 195 NEC and 125 EC were collected from the Hudson Valley, New York, in the winter of 2013-2014. Centrifugal fecal floats were performed in Sheather's sugar solution, and parasite ova and cysts were examined microscopically to identify gastrointestinal parasites present. For all pellets combined (n = 320), 91% were found to harbor at least 1 parasite species, with Eimeria species being the most common. Genetic analysis of pellets using microsatellite DNA identified 248 individual rabbits, with parasite prevalence (94%) similar to the prevalence estimate based on all pellets (91%). EC samples had a significantly higher (p < 0.05) parasite species richness (1.73, range 0-4) than NEC (1.20, range 0-3). EC and NEC shared 3 moderate to high (9-89%) prevalence parasites, in which EC prevalence was consistently higher. One parasite species was only found in NEC, and two were only found in EC, but the majority of these were of low abundance, precluding further statistical analyses.

Individual genotypes from environmental DNA: Fingerprinting snow tracks of three large carnivore species.

Continued advancements in environmental DNA (eDNA) research have made it possible to access intraspecific variation from eDNA samples, opening new opportunities to expand non-invasive genetic studies of wildlife populations. However, the use of eDNA samples for individual genotyping, as typically performed in non-invasive genetics, still remains elusive. We present successful individual genotyping of eDNA obtained from snow tracks of three large carnivores: brown bear (Ursus arctos), European lynx (Lynx lynx) and wolf (Canis lupus). DNA was extracted using a protocol for isolating water eDNA and genotyped using amplicon sequencing of short tandem repeats (STR), and for brown bear a sex marker, on a high-throughput sequencing platform. Individual genotypes were obtained for all species, but genotyping performance differed among samples and species. The proportion of samples genotyped to individuals was higher for brown bear (5/7) and wolf (7/10) than for lynx (4/9), and locus genotyping success was greater for brown bear (0.88). The sex marker was typed in six out of seven brown bear samples. Results for three species show that reliable individual genotyping, including sex identification, is now possible from eDNA in snow tracks, underlining its vast potential to complement the non-invasive genetic methods used for wildlife. To fully leverage the application of snow track eDNA, improved understanding of the ideal species- and site-specific sampling conditions, as well as laboratory methods promoting genotyping success, is needed. This will also inform efforts to retrieve and type nuclear DNA from other eDNA samples, thereby advancing eDNA-based individual and population-level studies.

An experimental design for obtaining DNA of a target species and its diet from a single non-invasive genetic protocol.

Next-generation sequencing technology has enabled accurate insights into the diet of wildlife species. The protocols for faecal sample collection and DNA extraction for diet analysis have differed from those focusing on target species, even in most studies combining questions on both aspects. We designed an experiment to evaluate two protocols using 11 parameters and select a single one that will generate both target species (Asiatic wild ass, Equus hemionus, in Israel) and diet DNA, as an effective strategy to minimise time, effort, and cost without hampering efficiency. In Protocol A, we swabbed the outer surface of faecal boluses and extracted DNA using a Stool Kit, while for Protocol B, we homogenised faecal matter from inside the bolus followed by extraction using a Powersoil Kit. Protocol A performed significantly better for four parameters, which included, for the target species, microsatellite amplification success and the quantity of the GAPDH gene; and for its diet, the number of exact sequence variants (ESVs) obtained at genus level and plant genus richness. However, there was no significant difference in the amplification success of sex-linked and plant markers, total reads at genus level, number of genera obtained and plant genus composition. Although we chose Protocol A, both protocols yielded results for the target species and its diet, demonstrating that one single protocol can be used for both purposes, although a pilot study is recommended to optimise the protocol for specific systems. This strategy may also be useful for studies combining target species and their gut microbiome and parasitic load.

Density-habitat relationships of white-tailed deer (Odocoileus virginianus) in Finland.

In heterogeneous landscapes, resource selection constitutes a crucial link between landscape and population-level processes such as density. We conducted a non-invasive genetic study of white-tailed deer in southern Finland in 2016 and 2017 using fecal DNA samples to understand factors influencing white-tailed deer density and space use in late summer prior to the hunting season. We estimated deer density as a function of landcover types using a spatial capture-recapture (SCR) model with individual identities established using microsatellite markers. The study revealed second-order habitat selection with highest deer densities in fields and mixed forest, and third-order habitat selection (detection probability) for transitional woodlands (clear-cuts) and closeness to fields. Including landscape heterogeneity improved model fit and increased inferred total density compared with models assuming a homogenous landscape. Our findings underline the importance of including habitat covariates when estimating density and exemplifies that resource selection can be studied using non-invasive methods.

From poops to planning: A broad non-invasive genetic survey of large mammals from the Indian Himalayan Region.

Large forested landscapes often harbour significant amount of biodiversity and support mankind by rendering various livelihood opportunities and ecosystem services. Their periodic assessment for health and ecological integrity is essential for timely mitigation of any negative impact of human use due to over harvesting of natural resources or unsustainable developmental activities. In this context, monitoring of mega fauna may provide reasonable insights about the connectivity and quality of forested habitats. In the present study, we conducted a largest non-invasive genetic survey to explore mammalian diversity and genetically characterized 13 mammals from the Indian Himalayan Region (IHR). We analyzed 4806 faecal samples using 103 autosomal microsatellites and with three mitochondrial genes, we identified 37 species of mammal. We observed low to moderate level of genetic variability and most species exhibited stable demographic history. We estimated an unbiased population genetic account (PGAunbias) for 13 species that may be monitored after a fixed time interval to understand species performance in response to the landscape changes. The present study has been evident to show pragmatic permeability with the representative sampling in the IHR in order to facilitate the development of species-oriented conservation and management programmes.

Italian wolves (Canis lupus italicus Altobello, 1921) and molecular detection of taeniids in the Foreste Casentinesi National Park, Northern Italian Apennines.

After centuries of massive decline, the recovery of the wolf (Canis lupus italicus) in Italy is a typical conservation success story. To learn more about the possible role of parasites in the wolves' individual and population health and conservation we used non-invasive molecular approaches on fecal samples to identify individual wolves, pack membership, and the taeniids present, some of which are zoonotic. A total of 130 specimens belonging to 54 wolves from eight packs were collected and examined. Taeniid eggs were isolated using a sieving/flotation technique, and the species level was identified by PCR (gene target: 12S rRNA and nad1). Taeniid prevalence was 40.7% for Taenia hydatigena, 22.2% for T. krabbei, 1.8% for T. polyachanta and 5.5% for Echinococcus granulosus. The prevalence of E. granulosus is discussed. Our results show that the taeniid fauna found in wolves from the Foreste Casentinesi National Park is comparable to that described for other domestic and wild Italian canids and provides insights into the wolves' diet and their relationship with the environment.

Big bad wolf or man's best friend? Unmasking a false wolf aggression on humans.

The return of the wolf in its historical range is raising social conflicts with local communities for the perceived potential threat to people safety. In this study we applied molecular methods to solve an unusual case of wolf attack towards a man in the Northern Italian Apennines. We analysed seven biological samples, collected from the clothes of the injured man, using mtDNA sequences, the Amelogenin gene, 39 unlinked autosomal and four Y-linked microsatellites. Results indicated that the aggression was conducted by a male dog and not by a wolf nor a wolf x dog hybrid. Our findings were later confirmed by the victim, who confessed he had been attacked by the guard dog of a neighbour. The genetic profile of the owned dog perfectly matched with that identified from the samples previously collected. Our results prove once again that the wolf does not currently represent a risk for human safety in developed countries, whereas most animal aggressions are carried out by its domestic relative, the dog.