Researchers eventually found that these sheep suffer from Tay-Sachs disease. This discovery is leading to advancements in a possible treatment for humans who have the disease. (Matt McClain/The Washington Post)

No one can say for sure if today’s Jacob sheep are direct descendants of the flock built by the Jewish patriarch Jacob. But with their unusual spotted wool, they resemble the sheep described in the beginning of the Old Testament.

The biblical story of Jacob and his herd describes an early example of selective sheep breeding. Similar unusual-looking sheep are depicted in Egyptian art around the time Jacob is recorded moving his family and flock there; later art traces their migration into Europe, according to the Jacob Sheep Conservancy.

The breed has been called piebald, spotted and even Spanish (after a story that they washed ashore in England from a sunken ship of the Spanish Armada). The association with Jacob started among 19th-century English aristocrats who raised the breed as curiosities and lawn ornaments.

Amid 20th-century efforts in England to conserve the vanishing breed, the name Jacob sheep stuck.

Fred Horak works on feeding and watering some of his Jacob sheep on his property in Gettysburg, Pa. He and his wife Joan noticed abnormalities in some of their sheep. (Matt McClain/The Washington Post)

The Jacob Sheep Society, Jacob Sheep Conservancy and Jacob Sheep Breeders Association agree on some basic facts. Jacob sheep today are a relatively pure Old World breed with roots in the Middle East, later introduced to continental Europe, England and eventually North America.

But the breeders groups differ in the degree to which they embrace a direct link with the patriarch, with some saying it is plausible and others dismissing it as romantic.

Jacob was the son of Isaac and grandson of Abraham, the three patriarchs of Judaism. In the story in Genesis, God promised Jacob he would be prosperous and revered, later renaming him Israel and saying his kin would be known as the Israelites. The Koran also recognizes Jacob as a prophet.

In Genesis, young Jacob fled his ancestral home after he fooled his aging father into blessing him instead of first-born brother, Esau. Jacob took refuge with his maternal uncle, Laban.

Immediately falling in love with Laban’s beautiful daughter, Rachel, Jacob agreed to manage his uncle’s flocks for seven years in exchange for her hand in marriage. But on the wedding night, Laban substituted his less attractive daughter, Leah.

Confronted the next morning, Laban agreed to let Jacob also wed Rachel (polygamy was common then) if he tended the sheep another seven years. The flock grew so much that after Jacob fulfilled his latest promise, Laban asked Jacob to continue.

Jacob agreed, if he could keep any spotted or piebald sheep that were born, leaving Laban the black-coated sheep he prized. Jacob solely used his spotted rams to breed, quickly building his multi-hued flock.

No Jacob sheep are in Israel today, although Canadian breeders are trying to introduce them. Jacob sheep imports to North America, mostly from England, started in the early 20th century.