The application, called pawlineR, was created by a team led by Steven R. Talbot at the Institute for Laboratory Animal Science and published in Frontiers in Veterinary Science. It addresses a well-known yet persistent challenge in cat breeding: while many breeders are aware of the genetic risks of inbreeding, practical tools for monitoring and managing genetic diversity have remained largely inaccessible to non-specialists.
Excessive inbreeding can lead to the buildup of harmful genetic variants, lowered fertility, and a higher risk of hereditary diseases. Inbreeding depression is generally considered biologically meaningful when the inbreeding coefficient exceeds F = 0.10. When researchers tested the tool on a historical dataset of 70 cats, 24 animals displayed moderate-to-high inbreeding levels, showing that the issue is far from purely theoretical.
pawlineR automates pedigree entry, validates parent-offspring relationships, and calculates inbreeding coefficients based on Wright's established formula. A notable feature is "virtual breeding," which allows users to simulate hypothetical matings and assess the expected inbreeding of prospective offspring before committing to an actual pairing. Manual validation confirmed the reliability of the calculations, though the authors note that accuracy depends on the completeness of the underlying pedigree data.
Built in R and designed to run in any standard web browser, the tool lowers the technical barrier for breeders who may not have a background in population genetics. While developed with cat breeding in mind, its architecture is extensible to other species as well. pawlineR is freely available for non-commercial use on GitHub and can be run locally through R/RStudio or hosted on a private Shiny server.
Dr. Lena Brix, a member of the research team, said
“Having a reliable and easily accessible tool for planning our breeding program has been a game-changer. Kinship between individual cats must always be considered when breeding, but assessing it across generations can be difficult. In a limited gene pool, inbreeding can occur quickly, leading to small litters and hereditary diseases. Having access to this simple tool has already helped us improve our cat breeding practices, and it will continue to do so in the future.”