The surprise bid by the big drugmaker caught a good many people off guard, including Genentech ceo Art Levinson, who is expected to meet with Roche chairman Franz Humer this evening to talk about integrating the two companies and who will play what role in making that happen. Roche, you may recall, already owns 56 percent of Genentech and plans to shift many operations to California.

Genentech, of course, has a different culture than Roche. One is a biotech, albeit a large one, that works to preserve an entrepreneurial mindset. The other is a lumbering drugmaker that favors traditional top-down edicts. So imagine Levinson’s surprise when he received a phone call Sunday night from Humer about the offer, as The Wall Street Journal reports.

There is always fallout from a deal, but retaining Genentech managers and scientists is important to Roche’s success if something more than a product portfolio is to be gotten. “We will do everything to preserve the unique and science-driven culture of Genentech, something which made Genentech so successful and something we want to build on,” Severin Schwan, Roche’s ceo, tells the paper.

But what of Roche execs? At a meeting late yesterday with hundreds of Roche managers in Nutley, New Jersey, Pascal Soriot, who runs oversees the global pharma commercial business, tried to soothe the troops, by saying there will be job opportunities. However, George Abercrombie, who heads the US pharma business (pictured right), repeatedly emphasized that consolidation is coming and, interestingly, was mute about his own future, sources say.

A Roche spokesman declined to discuss George’s role, saying such decisions are premature. “There will be a selection process down the line,” he tells us.