Mayra Mendoza carefully adjusted the microscope, her eyes fixed on a pattern of striped rods—chromosomes from an aardwolf, a shy, termite-eating creature of the African savanna. For the first time, scientists had mapped its full set of chromosomes in vivid detail, revealing a quiet miracle of evolution: despite 11 million years of separate journeys, the aardwolf’s chromosomes look nearly identical to those of the spotted hyena—and surprisingly similar to those of a house cat.
This discovery matters because chromosomes are the blueprints of life. Until now, almost nothing was known about the aardwolf’s genetic structure beyond its chromosome count of 40, recorded decades ago. With only about 1,200 of the world’s 6,000 mammal species having detailed chromosome maps, each new study fills a vital gap. “You never know when a species might become extinct,” says Dr. Terje Raudsepp of Texas A&M, who led the study with the Twin Pine Conservation Institute.
The team used a skin sample from an aardwolf to grow cells and capture chromosomes during cell division. Using a staining technique that creates barcode-like stripes, they compared the patterns to those of spotted hyenas. The match was striking—only three of the 20 chromosome pairs differed. Even more surprising was what happened when they compared aardwolves to domestic cats using DNA 'painting.' Though cats and aardwolves split from a common ancestor about 33 million years ago, 12 of the cat’s 19 chromosomes aligned one-to-one with aardwolf chromosomes.
“This stability is rare,” Mendoza said. “The colors don’t look like they belong to two different species.” The study also found that a key genetic region—the nucleolus organizer region, or NOR—sits in the same spot in aardwolves, hyenas, and cats, from housecats to lions. This shared feature, usually variable across species, suggests a deep evolutionary link. Despite their dog-like appearance, hyenas are genetically closer to cats than to canines.
The work opens doors for future genome sequencing, helping scientists piece together fragmented DNA with precision. It also highlights how much remains unknown—of the 6,000 mammal species, most still lack chromosome maps. But each discovery, like this one, reminds us that life’s blueprint often holds quiet, enduring patterns. As Raudsepp puts it: even in the wild, some things change very slowly.