This , Andersen told , “ means ’ effective infecting human cells. ” The significant trait , rare insertion genome twelve nucleotides , called furin cleavage site , might also increase virus ’ transmissibility , lower species barrier , allowing virus jump easily humans. “ One look really closely sequences see features ( potentially ) look engineered , ” wrote.There much data analyze , continued , “ opinions could still change. ” A day later , Andersen joined conference call group prominent virologists government officials , including Fauci Francis Collins , director National Institutes Health.Andersen presented summary notable features SARS-CoV-2 genome , asked group , “ Do think unusual ? ” Fauci recalled , among participants , opinions divided. “ Knowledgeable people saying , It look like could something might engineered , ’ something usually see , ” told .