News Summary: Myriad stock volatile on gene ruling

ROLLERCOASTER REACTION: Diagnostic test maker Myriad Genetics saw its shares jump 10 percent, then plunge. The volatility was triggered by the Supreme Court's mixed ruling on the validity of patents for lucrative test for genes linked to high risk of hereditary breast and ovarian cancer.

SPLIT DECISION: The court said Myriad can't patent the genes involved — the decision company rivals and university scientists wanted. But the ruling upholds two dozen patents covering synthetically created genetic material and the specific process Myriad uses in testing genes for susceptibility to cancer.

WIDER IMPACT: Rivals will eventually be able to create their own tests, benefiting patients.