From the L.A. Times Technology blog:

Bertrand Serlet, Apple’s senior vice president of Mac software engineering, announced Wednesday morning that he’s leaving the Cupertino tech giant.

Serlet, whom many have called “the father of Mac OS X,” has worked alongside Apple’s Chief Executive Steve Jobs for more than two decades at both Apple and NeXT, the short-lived computer company that Jobs started after being forced to leave Apple in 1985.

Jobs returned to Apple in 1996 in a deal that saw Apple buy NeXT, and in 1997 he hired Serlet to head the development of Mac OS X.

“I’ve worked with Steve for 22 years and have had an incredible time developing products at both NeXT and Apple, but at this point, I want to focus less on products and more on science,” Serlet said in a statement issued by Apple.

Replacing Serlet will be Craig Federighi, Apple’s current vice president of Mac software engineering. Federighi will take over Serlet’s role as senior VP of Mac software and, like Serlet, report to Jobs.

Photo: Bertrand Serlet, left, and Craig Federighi in 2009. Credit: Robert Galbraith / Reuters