UPDATE 2-Apple shares slide 12 percent after weak results

Jan 24- Apple Inc's shares slumped 12 percent on Thursday, slicing more than $50 billion from its market value, as weaker-than-expected holiday iPhone sales reinforced fears that it is losing its dominance in smartphones. Jefferies& Co cut its rating on Apple's stock to "hold" from "buy" and slashed its share price target by $300 to $500.