' s ▁version ▁of ▁the ▁theory ▁life ▁evol ved ▁in ▁two ▁stages , ▁widely ▁separated ▁in ▁time . ▁Because ▁of ▁the ▁bio chem istry ▁he ▁regards ▁it ▁as ▁too ▁unlikely ▁that ▁gen es ▁could ▁have ▁developed ▁fully ▁blow n ▁in ▁one ▁process . ▁Current ▁cells ▁contain ▁ad en os ine ▁tri ph osph ate ▁or ▁ATP ▁and ▁ad en os ine ▁ 5 '- mon oph osph ate ▁or ▁A MP , ▁which ▁greatly ▁res emble ▁each ▁other ▁but ▁have ▁completely ▁different ▁functions . ▁ATP ▁trans ports ▁energy ▁around ▁the ▁cell , ▁and ▁A MP ▁is ▁part ▁of ▁R NA ▁and ▁the ▁gen etic ▁appar atus . ▁D ys on ▁proposed ▁that ▁in ▁a ▁primitive ▁early ▁cell ▁containing ▁ATP ▁and ▁A MP , ▁R NA ▁and ▁rep lication ▁came ▁into ▁existence ▁only ▁because ▁of ▁the ▁similarity ▁between ▁A MP ▁and ▁R NA . ▁He ▁suggested ▁that ▁A MP ▁was ▁produced ▁when ▁ATP ▁mole cules ▁lost ▁two ▁of ▁their ▁ph osph ate ▁radical s , ▁and ▁then ▁one ▁cell ▁somewhere ▁performed ▁E igen ' s ▁experiment ▁and ▁produced ▁R NA . ▁ ▁There ▁is ▁no ▁direct ▁evidence ▁for ▁the ▁dual ▁origin ▁theory , ▁because ▁once ▁gen es ▁developed , ▁they ▁took ▁over , ▁ob liter ating ▁all ▁traces ▁of ▁the ▁earlier ▁forms ▁of ▁life . ▁In ▁the ▁first ▁origin , ▁the ▁cells ▁were ▁probably ▁just ▁dro ps ▁of ▁water ▁held ▁together ▁by ▁surface ▁t ension , ▁te em ing ▁with ▁en zym es ▁and ▁chemical ▁re actions , ▁and ▁having ▁a ▁primitive ▁kind ▁of