Pacific Biosciences: Michael Hunkapiller, Susan Barnes

Pacific Biosciences announced that CEO and President Michael Hunkapiller will retire by the end of the year. He plans to remain on the company's board. Hunkapiller served eight years as CEO and oversaw the launch of the Sequel and Sequel II instruments.

Susan Barnes, the firm's CFO and executive VP, will also retire in August after more than a decade with the company.

PacBio said it has already begun searching for their replacements.