Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of molecular diagnostics company Myriad Genetics (NASDAQ:MYGN) fell as much as 13% following yesterday's mixed U.S. Supreme Court ruling on gene patents and a flurry of analyst upgrades and downgrades in wake of that news.

So what: The more immediate implication sending Myriad lower was the Supreme Court's findings that genes already present in the human body (e.g., BRCA1, BRCA2) cannot be patented -- only synthetic genetic material may be patented. This means the patent tactics it had used to keep competitors from introducing a BRCA molecular test in competition to its BRACAnalysis test will no longer work, and it's now merely a race to bring new genetic tests to market -- likely at a big discount to Myriad's current price.

Also pressuring Myriad were mixed analyst reactions to the news. Bank of America/Merill Lynch downgraded the company to "neutral" from "buy," while JMP Securities actually upgraded the company to "outperform" from "market perform" with a $48 price target, citing the removal of the court ruling overhang.

Now what: I happen to like molecular diagnostic companies, including Myriad Genetics, but it's still too early to see how this ruling may impact Myriad's bottom line. The long run thesis of molecular diagnostics companies appears intact in that as long as the costs associated with genetic analysis continues to fall the allure of developing personalized treatment plans for patients grows. I'd suggest avoiding the analyst white noise and keeping your eyes and ears peeled to see what Myriad has to say about its forecast for the remainder of the year.

Craving more input? Start by adding Myriad Genetics to your free and personalized watchlist so you can keep up on the latest news with the company.

Fool contributor Sean Williams owns shares of Bank of America, but has no material interest in any other companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong.

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