The last executive with links to both Google and Apple has resigned from Google's board of directors today, taking a bite out of an ongoing US investigation into the companies' entanglements.

Genentech chairman Arthur Levinson, who has sat on the boards of both Google and Apple, today resigned from Google's board, effective immediately, Google announced.

Google gave no reason for Levinson’s departure, but earlier this year, the Federal Trade Commission began an antitrust investigation into the close ties between the boards of Google and Apple.

"Art has been a key part of Google's success these past five years, offering unvarnished advice and vital counsel on every big issue and opportunity Google has faced," said Google Chairman and CEO Eric Schmidt in a statement. "Though he leaves as a member of our board, Art will always have a special place at Google."

Levinson had been on Google's board since April 2004.

Analysts said the resignation should end the Federal Trade Commission investigation into whether Apple and Google violated antitrust laws by sharing directors. Google CEO Eric Schmidt resigned from the Apple board a few months after the FTC investigation was initiated last spring.

"Looks like the board conflicts between Apple and Google have finally been straightened out with Levinson resigning from Google's board," said Dan Olds, an analyst with The Gabriel Consulting Group.

"This should put to rest any government investigation, at least on these issues. Levinson needed to do this and probably should have done it right after Schmidt left Apple's board. I'm not sure why he waited this long, unless he was having a hard time making up his mind."

The FTC has yet to update the status of the probe after today's resignation of Levinson, the only remaining director to sit on both boards.

The FTC had heightened its focus on Levinson and Schmidt's roles on both boards along with the increased competition between Google and Apple.

For example, Google's Chrome browser competes directly with Apple's Safari, while Google's Android mobile device platform goes head-to-head with Apple's popular iPhone .

That competition grew a little more heated when, just last month, Google announced the Chrome OS , which will go up against desktop operating systems like Apple's Mac OS X.