By MARCY GORDON
AP Business Writer
WASHINGTON (AP) — The senator leading a probe of Facebook’s Instagram and its impact on young people is asking Facebook CEO Mark Zuckerberg to testify in the Senate. Zuckerberg is being asked to appear before the panel that has heard far-reaching criticisms from a former employee of the company. Sen. Richard Blumenthal heads the Senate Commerce subcommittee on consumer protection. He called on Zuckerberg in a sharply worded letter to testify on Instagram’s effects on children’s mental health and wellbeing. As public discomfort and scrutiny of the social network giant has grown in recent weeks, the focus has homed in on Zuckerberg, who controls over 50% of Facebook’s voting shares.