Genome of Texas Longhorn, related breeds tells global history of human, cattle migration

Emily Jane McTavish, a doctoral student in the lab of UT Biology professor David Hillis, hanging out with some of the Longhorns at Hillis's Double Helix Ranch. Credit: Photo by Liz Milano

Texas Longhorn cattle have a hybrid global ancestry, according to a study by University of Texas at Austin researchers published this week in the Proceedings of the National Academy of Sciences.

The study of the genome of the Longhorn and related breeds tells a fascinating global history of human and cattle migration. It traces back through Christopher Columbus' second voyage to the New World, the Moorish invasion of Spain and the ancient domestication of the aurochs in the Middle East and India.

"It's a real Texas story, an American story," said Emily Jane McTavish, a doctoral student in the lab of biology professor David Hillis. "For a long time people thought these New World cattle were domesticated from a pure European lineage. But it turns out they have a more complex, more hybrid, more global ancestry, and there's evidence that this genetic diversity is partially responsible for their greater resilience to harsh climatic conditions."

To reconstruct the genetic history of Texas Longhorns, McTavish, Hillis and colleagues from the University of Missouri-Columbia analyzed almost 50,000 genetic markers from 58 cattle breeds. The most comprehensive such analysis to date, it was funded in part by the Cattlemen's Texas Longhorn Conservancy, which helped the scientists get access to samples used by ranchers.

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The study of the genome of the Texas Longhorn and related breeds, animated here, tells a fascinating global history of human and cattle migration. It traces back through Christopher Columbus' second voyage to the New World, the Moorish invasion of Spain and the ancient domestication of the aurochs in the Middle East and India. Animation by Marianna Grenadier

Over the next two centuries the Spanish moved the cattle north, arriving in the area that would become Texas near the end of the 17th century. The cattle escaped or were turned loose on the open range, where they remained mostly wild for the next two centuries.

"It was known on some level that Longhorns are descendants from cattle brought over by early Spanish settlers," said Hillis, the Alfred W. Roark Centennial Professor in the College of Natural Sciences, "but they look so different from the cattle you see in Spain and Portugal today. So there was speculation that there had been interbreeding with later imports from Europe. But their genetic signature is co mpletely consistent with being direct descendants of the cattle Columbus brought over."

The study reveals that being a "pure" descendant of cattle from the Iberian peninsula indicates a more complicated ancestry than was understood. Approximately 85 percent of the Longhorn genome is "taurine," descended from the ancient domestication of the wild aurochs that occurred in the Middle East 8,000-10,000 years ago. As a result, Longhorns look similar to purer taurine breeds such as Holstein, Hereford and Angus, which came to Europe from the Middle East.

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Genome of Texas Longhorn, related breeds tells global history of human, cattle migration