ferret out

「〔事実などを〕探し出す」。

ferretは、「白イタチ」。ウサギやネズミを追い出すのに使われていた（る？）そうです。

The New York Timesの記事、'A Decade Later, Human Gene Map Yields Few New Cures' By NICHOLAS WADEから。

'Ten years after President Bill Clinton announced that the first draft of the human genome was complete, medicine has yet to see any large part of the promised benefits.

For biologists, the genome has yielded one insightful surprise after another. But the primary goal of the $3 billion Human Genome Project — to ferret out the genetic roots of common diseases like cancer and Alzheimer’s and then generate treatments — remains largely elusive. Indeed, after 10 years of effort, geneticists are almost back to square one in knowing where to look for the roots of common disease'.