P'ru ur'vu

For P, the general theme of the book of Genesis is how God chose the blessed nation. Originally all animals were blessed, then just man, then just Noach, then just Avraham, then Yishmael, then Yaakov. Each time, one single descendent was chosen to carry the torch (so you see P believed in evolution). Specifically, the blessing is "p'ru u'rvu" which appears 10 times in Chumash (Gen 1:22 1:28 , 9:1, 9:7 17:20 28:3 35:11 47:27 48:4 Ex 1:7) Relevant similar verses are Gen 41:52 (P - hifrani) Gen 17:6 (P -just p'ru) 50:22 (not P - Porath).

There are two principal weaknesses to this argument. Firstly, the grounds for assigning Gen 47:27 and Ex 1:7 are weak. Secondly, 50:22 is a very similar verse and is not in P. Moreover, many of the verses that are in P are assigned to P on the grounds of an adjacent "Kel Shakai" the Holy name associated with P. However, Gen 50:22 is also adjacent to another "Shakai" in 50:25. This opens the door to arguing the correlation is not one of authorship but of some similarity between the name Shakai and the word p'ru. Perhaps Shakai signifies the Fertility God. In many primitive cultures, figurines of fertility goddesses were created to have large shaddaim.

On the other hand, most of these passages have other reasons to be assigned to P anyway. And, the weight to which these verses are slanted towards P is great no matter how one approaches the few questionable verses.