In an earlier hypothesis, Carl Woese (1988) had proposed that: (1) no individual organism can be considered a LUCA, and (2) the genetic heritage of all modern organisms derived through horizontal gene transfer among an ancient community of organisms.
En 1998, Carl Woese propuxo o seguinte: (1) ningún organismo en particular pode considerarse un último antepasado universal, e (2) a herdanza xenética de todos os organismos modernos derivaba da transferencia horizontal de xenes entre as comunidades antigas de organismos.