The merger of Russian gas giant Gazprom and oil firm Rosneft is to go ahead, but will not include Yugansk, which was controversially bought last year.The merger, backed by Russian authorities, will allow foreigners to trade in Gazprom shares.Gazprom chief Alexei Miller confirmed Rosneft-owned Yugansk was not part of the deal and will instead be spun off.Under the agreement, the state will get a controlling share of Gazprom in exchange for Rosneft.The state wanted to control Gazprom before allowing foreigners to trade.