How We Bred a Cow into a Biological Disaster

What the film says

1. In 1997 Se-Jin Lee and colleagues knocked out the myostatin gene in mice, which developed about twice the normal muscle.

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2. The Belgian Blue's double muscling comes from a mutation in the myostatin gene; myostatin normally inhibits muscle growth.

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3. The mutation also interferes with fat deposition, producing very lean meat.

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4. The breed was originally dual-purpose (dairy and beef).

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5. Professor Hanset developed the modern beef type at an artificial insemination centre in Liège Province, fixing the mutation through linebreeding.

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6. Belgian Blue cows commonly deliver by caesarean section.

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7. A 2006 Theriogenology study found that 93.7% of young Belgian Blue bulls failed breeding soundness exams, compared with 59.3% of Holsteins.

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8. In 1997, three research teams independently found the same 11-base-pair deletion in the myostatin gene, and Se-Jin Lee's lab was one of them.

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