Parasite exchange and hybridisation at a wild-feral-domestic interface.

Interactions between wild, feral, and domestic animals are of economic and conservation significance. The pigeon Columba livia is a synanthropic species in a feral form, but it also includes the rare Rock Dove. Columba livia is an important player at the wild-domestic interface, acting as a carrier of avian diseases, and the feral form threatens Rock Doves with extinction via hybridisation. Despite its abundance, little is known about drivers of disease prevalence in C. livia, or how disease and hybridisation represent synergistic threats to Rock Doves. We focused on infection by the parasite Trichomonas, first collating prevalence estimates in domestic and free-living populations from relevant studies of C. livia. Second, we characterised variation in the diversity and prevalence of Trichomonas among three C. livia populations in the United Kingdom: a feral, a Rock Dove, and a feral-wild hybrid population. Across multiple continents, free-living pigeons had lower Trichomonas infection than captive conspecifics, but the effect was weak. Environmental factors which could impact Trichomonas infection status did not explain variation in infection among populations. Among the British populations, strain diversity varied, and there was lower parasite prevalence in Rock Doves than feral pigeons. Individual infection status was not explained by the available covariates, including hybrid score and site. The drivers of Trichomonas prevalence are unclear, perhaps due to idiosyncratic local-scale drivers. However, given the population-level variation in both infection prevalence and introgressive hybridisation, the potential combined effects could accelerate the extinction of the Rock Dove. Further study of the synergistic effects of multiple types of biotic interactions at the wild-feral-domestic interface is warranted, especially where vagile, globally distributed and superabundant animals are involved.

Limited domestic introgression in a final refuge of the wild pigeon.

Domesticated animals have been culturally and economically important throughout history. Many of their ancestral lineages are extinct or genetically endangered following hybridization with domesticated relatives. Consequently, they have been understudied compared to the ancestral lineages of domestic plants. The domestic pigeon Columba livia, which was pivotal in Darwin's studies, has maintained outsized cultural significance. Its role as a model organism spans the fields of behavior, genetics, and evolution. Domestic pigeons have hybridized with their progenitor, the Rock Dove, rendering the latter of dubious genetic status. Here, we use genomic and morphological data from the putative Rock Doves of the British Isles to identify relictual undomesticated populations. We reveal that Outer Hebridean Rock Doves have experienced minimal levels of introgression. Our results outline the contemporary status of these wild pigeons, highlighting the role of hybridization in the homogenization of genetic lineages.

The wild ancestors of domestic animals as a neglected and threatened component of biodiversity.

Domestic animals have immense economic, cultural, and practical value and have played pivotal roles in the development of human civilization. Many domesticates have, among their wild relatives, undomesticated forms representative of their ancestors. Resurgent interest in these ancestral forms has highlighted the unclear genetic status of many, and some are threatened with extinction by hybridization with domestic conspecifics. We considered the contemporary status of these ancestral forms relative to their scientific, practical, and ecological importance; the varied impacts of wild-domestic hybridization; and the challenges and potential resolutions involved in conservation efforts. Identifying and conserving ancestral forms, particularly with respect to disentangling patterns of gene flow from domesticates, is complex because of the lack of available genomic and phenotypic baselines. Comparative behavioral, ecological, and genetic studies of ancestral-type, feral, and domestic animals should be prioritized to establish the contemporary status of the former. Such baseline information will be fundamental in ensuring successful conservation efforts.

Los Ancestros de Animales Domésticos como un Componente Descuidado y Amenazado de la Biodiversidad Resumen Los animales domésticos tienen un inmenso valor económico, cultural y práctico y han jugado un papel muy importante en el desarrollo de la civilización humana. Muchos animales domesticados tienen, entre sus parientes silvestres, formas no domesticadas representativas de sus ancestros. Un interés renovado en estas formas ancestarles ha destacado el estatus genético poco claro de muchas, y algunas están amenazadas de extinción por hibridación con conespecíficos domesticados. Consideramos el estatus contempóraneo de estas formas ancestrales en relación con su importancia científica, práctica y ecológica; los impactos diversos de la hibridación silvestre-domesticado; y los retos y soluciones potenciales involucrados en los esfuerzos de conservación. La identificación y conservación de formas ancestrales, particularmente en relación con desenredar patrones de flujo génicos, es compleja debido a la carencia de líneas de base genómicas y fenotípicas. Se deben priorizar estudios conductuales, ecológicos y genéticos comparativos de los animales ancestrales, ferales y domésticos para establecer el estatus contemporáno de los primeros. Tal información de base será fundamental para asegurar esfuerzos de conservación exitosos.