Can I ask for a little clarification of the Dirk/Roxy Jane/Jake not being related? Why aren't they ectosiblings like Dave/Rose John/Jane were? I'm a little confused here.

Dirk, Roxy, Jane, and Jake are clones of their pre-scratch selves while John and Jade were made with Jake and Jane’s ectoslime and Rose and Dave were created by mixing Roxy and Dirk’s ectoslime