Asian shares sagged in early trading and a drop in Treasury yields pressured the dollar after news of a downed Malaysian airlines jet at the Ukraine-Russia border sent investors scurrying into defensive assets. “The prospect of further international punishment for Russia on the world’s stage, if indeed the downing of the Malaysian airliner had anything to do with its forces, clearly shocked speculative forces into seeking defensive positions immediately,” Andrew Wilkinson, chief market analyst at Interactive Brokers LLC, said in a note to clients.