Senju DNA

[MasterofSenjutsu]

I was just thinking, if such a small amount of senju dna can allow yamato to use wood style, shouldnt someone like tsunade, who is the grandchild of hashirama, be able to use it to? tsunade might be a bad example because shes useless but shouldnt other kids of hashirama be able to use it? im sure they would have more dna of hashirama than the test subjects do

I think it's because it is Hashi's direct DNA. Tsunade's own DNA is different than Hashi's. In biology (I'm kinda rusty on this), you get DNA from both your parents. Since Yamato was created, he just had Hashi's DNA. I think this allowed him to do Mokuton.