Fox Genomes Point to Adaptations to Extreme Sahara Desert Environment

Researchers sequenced the genomes of foxes belonging to different species from the genus Vulpes to gain insight into how they adapted to life in the Sahara Desert. In particular, they sequenced 82 individual foxes: 30 North African and 18 Eurasian red foxes; 24 North African Rueppell's foxes; five fennec foxes; and five pale foxes, all of which colonized the Sahara at different times. As they report in Nature Ecology & Evolution, the researchers found that Rueppell's fox diverged from the red fox about 576,000 years ago with Rueppell's fox moving into extreme desert environments and the red fox dispersing into Eurasia and later, about 78,000 years ago, to North Africa. The researcher further uncovered a region of the Rueppell's fox genome that has introgressed into red foxes of North Africa. They also noted signatures of selection affecting genes involved in water homeostasis in Rueppell's fox and the fennec fox, both of which are extreme desert specialists, and physiological analysis found they are better able to retain water when dehydrated. "We propose that genetic variation shared among core desert species is an important component of recent or ongoing adaptation to rapidly changing climates in foxes living at the edge of deserts," the researchers write. "Our findings may thus help address questions concerning the persistence and adaptive capacity of biodiversity currently challenged by desertification."