A population on the brink
In 2002, the Iberian lynx (Lynx pardinus) was the world's most endangered feline, with fewer than 100 individuals remaining in the wild. These survivors were split into two isolated populations in Andalusia: one in the Sierra Morena mountains and a smaller, more threatened group in Doñana National Park. This extreme population bottleneck led to severe genetic problems. The Doñana lynx, in particular, showed clear signs of inbreeding depression.
Genomic analysis revealed the consequences of this limited gene pool. The average genome-wide heterozygosity (a measure of genetic diversity) was among the lowest recorded for any mammal. This lack of genetic variation had tangible effects on the cats' ability to survive. Litter sizes were shrinking, and the population was more vulnerable to diseases, such as a devastating feline leukemia virus outbreak in 2007. Most critically, the survival of kittens was severely compromised, with inbreeding directly reducing their chances of reaching adulthood.
A calculated genetic intervention
To save the Doñana population from an extinction vortex, conservation scientists implemented a genetic rescue plan. The strategy was to mimic natural gene flow by moving lynx between the two remaining wild populations. Beginning in 2007, individuals from the slightly more genetically diverse Sierra Morena population were translocated into Doñana. The goal was to introduce new alleles into the Doñana gene pool, increase heterozygosity, and combat the effects of inbreeding.
The results were swift and successful. Genetic monitoring confirmed a significant increase in genetic diversity and a reduction in average inbreeding within the Doñana population following the translocations. The offspring of mixed ancestry (F1 generation) showed higher reproductive success. This genetic refresh directly translated to healthier, more resilient animals. Within just two generations, the introduction of new genetic material had restored heterozygosity and reversed the downward trend in kitten survival. This intervention, part of a broader conservation effort including habitat restoration and captive breeding, has been successful. The total Iberian lynx population has since rebounded to over 2,000 individuals as of early 2024. In June 2024, the species' status on the IUCN Red List was improved from "Endangered" to "Vulnerable".