Democrat front-runner Hillary Clinton and rival Bernie Sanders are virtually deadlocked in California, the biggest prize of the 2016 Democratic presidential primary season, according to a new poll. The survey, conducted by the Public Policy Institute of California, finds Clinton with only a small lead over Sanders, 46 percent to 44 percent, among likely voters in the Democratic primary on June 7, Politico reported on Thursday. The poll also showed a majority of Republican primary voters will cast their ballots for the party's presumptive presidential nominee Donald Trump. California looms largest in the Democratic presidential race. However, Clinton is likely to clinch the nomination -- factoring in the expressed preferences of unpledged superdelegates -- even before polls close in California, the poll said. The PPIC poll showed the race breaking along familiar lines. Sanders holds a large advantage among younger voters -- leading 66 percent to 27 percent among voters under age 45 -- while Clinton leads, 59 percent to 28 percent, among voters 45 and older. But the survey showed only a small gender gap. Sanders holds a 4-point edge with men, and Clinton leads by 7 points among female voters. There’s also little difference between white voters, who favour Clinton by a 6-point margin, and Hispanics, who back the former secretary of state by 9 points. The poll was conducted over a relatively long period of time -- May 13-22 -- and surveyed 552 likely Democratic primary voters. Meanwhile, among likely Republican primary voters, about two-thirds, 67 percent, said they would vote for Trump. Just over a quarter, 26 percent, said they will vote for someone else.