<p>Hi I am trying to put together a plink ped file but I couldn't find how to depict missing maternal and paternal ids. You can give an argument if you have no parent ids in your file but I only miss some. For sex and phenotype you have missing data codes but what about the parental ids?
To put it differently how exactly do you depict the family relationships in the ped file format for plink?
Thanks </p>

<p>did you try to use '0' for the parental IDs ?</p>