дикая природа, идея 146

For centuries, Americans assumed the wild horses of the West were direct descendants of the mounts carried north by Spanish conquistadors. Genetic testing tells a more complicated story. After analyzing thousands of wild horses across hundreds of herds, researchers found that most mustangs are heavily mixed with later ranch and domestic bloodlines. But a small number of isolated herds in Montana, Utah, Arizona, and Oregon still carry measurable Iberian ancestry linked to the old Spanish horse. The mystery is how that ancestry survived five centuries of mixing, roundups, ranching, and population decline. Now newer genetic work suggests even these famous herds may be drifting away from their Spanish roots, creating a difficult conservation problem: isolation preserves the old bloodline, but too much isolation can also destroy the genetic diversity the horses need to survive.