Iberian wolves may have a unique nature due to past hybridization with dogs
A study led by the Doñana Biological Station has identified ancient dog genes in Iberian wolves. These genes may influence behavioural traits that set them apart from other European wolf populations, such as their tendency to travel shorter distances.
Several genes inherited from dogs also seem to boost immune system function, potentially helping Iberian wolves adapt more effectively to their environment

Iberian wolf. Credit: Isabel Salado
New international research led by the Estación Biológica de Doñana - CSIC reveals that Iberian wolves retain a small but significant genetic legacy from ancient encounters with dogs. This genetic heritage may contribute to their distinctive traits, including aspects of their immune system and behaviour. Published in Molecular Ecology, the study highlights how Iberian wolves have preserved their genetic uniqueness despite thousands of years of coexistence with domestic dogs in the Iberian Peninsula.
In response to concerns about wolf-dog hybridization, the researchers set out to investigate this phenomenon in depth. ‘We wondered whether the drastic decline of the Iberian wolf population in the 1970s had led to more frequent interbreeding with dogs,’ explains Carlos Sarabia, postdoctoral researcher at Brown University.
To conduct the research, the researchers analyzed 150 complete genomes of wolves and dogs from Europe and western Siberia. The fidings revealed that Iberian wolves have remained remarkably distinct from dogs, despite sharing the same territory for millennia. While contemporary hybridization is rare, the results indicate that these wolves retain a small fraction of dog DNA —less than 5%—, resulting from ancient encounters, possibly dating back to the arrival of humans with domesticated dogs in the region more than 10,000 years ago.
‘What makes this discovery particularly interesting is that some of these ancient dog genes seem to have been beneficial to wolves,’ says Isabel Salado, a postdoctoral researcher at the Doñana Biological Station (CSIC).
In the study, six key dog genes that show strong evidence of positive selection in Iberian wolves were identified. These genes play a role in immune response and brain functions, and may have contributed to the distinctive traits of the Iberian wolf, including dispersal behaviour, which differs significantly from that of other European wolves’ populations.
The genetic uniqueness of Iberian wolves
‘Natural selection has preserved these genes for thousands of years, suggesting that they play a crucial role in their immune system and possibly in their unique behavioural traits,’ says Jennifer A. Leonard, a researcher at the Doñana Biological Station (CSIC). ‘These findings confirm the distinct evolutionary path of Iberian wolves compared to other wolf population’.
According to this study, Iberian wolves may have maintained their wild nature while benefiting from a small number of dog-derived genes. These findings have important conservation implications, suggesting that Iberian wolves represent a distinct and valuable population that has evolved with specific adaptations to their environment in the Iberian Peninsula.
The study shows that, while hybridization between wild and domestic species is often seen in a negative light, it can sometimes enhace the adaptive potential of wild populations. ‘Despite concerns about wolf-dog hybridisation, this does not necessarily pose a threat for wolf conservation,’ says Carles Vilà, researcher at the Doñana Biological Station (CSIC).
This research provides new insights into how wild species can benefit from limited genetic exchange with their domesticated relatives while preserving their distinct identity.
Reference
Sarabia, C., Salado, I., Fernández-Gil, A., vonHoldt, B.M., Hofreiter, M., Vilà, C. and Leonard, J.A. (2025), Potential Adaptive Introgression From Dogs in Iberian Grey Wolves (Canis lupus). Molecular Ecology e17639. https://doi.org/10.1111/mec.17639
This study is part of the knowledge generation project ‘Frontera’ of the Junta de Andalucía (P18-FR-5099), with funding from the European project ‘WOLFNESS Biodiversia+, co-funded by the European Commission (GA N101052342) and the Spanish Ministry of Science and Innovation (PCI2022-135098-2), as well as a pre-doctoral contract from the Ministry of Universities (FPU17/02584) and a research contract from the ‘Apadrina la Ciencia’ Association, co-funded by the Ford Motor Company Fund. The article has been published in open access thanks to the Unidad de Recursos de Recursos de Información para la Investigación del CSIC (URICI).