In announcing a crackdown Friday on companies it says were involved in fraudulent genetic testing, the U.S. Department of Justice brought charges against 35 individuals associated with dozens of telemarketing companies and testing labs. The federal investigation, called Operation Double Helix, went after schemes that allegedly targeted people 65 and older. According to the charges, the schemes involved laboratories paying illegal kickbacks and bribes to medical professionals who were working with fraudulent telemarketers, in exchange for the referral of Medicare beneficiaries.