A Southborough man originally charged with murder in the death of his uncle in his Cape Cod vacation home has pleaded guilty to the lesser charge of manslaughter. Christopher Manoloules was scheduled for a status review Wednesday but instead entered a plea in the October 2009 shooting death of Aris Manoloules in his Hyannis home. The Cape Cod Times reported that Manoloules, 21, was sentenced to 12 to 15 years in prison, with credit for the nearly four years he has served while awaiting trial. Aris Manoloules’s brother-in-law, Robert Upton, was convicted of murder in January. The victim’s brother, Treefon, who had been charged with masterminding the killing, was acquitted.