Even at 7am in south-central Texas, a steamy mist envelops Austin, the state’s capital and pre-eminent college town. Monica Seidel cuts through the humidity in an SUV so big it overwhelms the driveway of her destination – a neat, prairie-style house in the old-money neighbourhood of Tarrytown.

Inside, Nick Fox is waiting. Fox, a partner at the law firm Vinson & Elkins, is catching a morning flight to New York City, but before flying, he will give Seidel two tablespoons of his blood. Barefoot and business-casual, he leads his lab-coat-cloaked guest into the kitchen, offers her coffee, then sits down and rolls up his sleeve. “Did you strike?” he asks, in the lingo of oil drilling, as Seidel begins to fill five small vials with his blood.