When he was a student at Yale, Henry Louis Gates Jr. took a course known as "biology for poets." Now the Harvard humanities scholar is a zealot of genetic science. Since his original "African American Lives" miniseries, which explored the heritage of black stars such as Oprah Winfrey and Quincy Jones, Mr. Gates has developed a broader approach—and a TV franchise. Featuring 25 guests ranging from Robert Downey Jr. to Condoleezza Rice, his new series, "Finding Your Roots," premiered in March. With this 10-part prime-time series, up from the four episodes in his last special from 2010, PBS has essentially doubled down on DNA. Click here to read more in The Wall Street Journal.