Harry not related to the Dursleys?

[sabotage3p3]

No: HPFGUIDX 55779

I was reading through the first book and was on chapter 12.  I've 
noticed while reading it that when Harry looked in the Mirror of 
Erised, he sees all of his family.  His mother, father, his 
grandparents, ancestors, etc.  He sees people from both is mothers 
and fathers side of the family and I just realized that he didn't 
see the Dursleys. No Aunt Petunia or Dudley... So does that mean 
that the Dursleys aren't related to Harry??  This also brings out 
more questions, like than how does Harry staying with the Dursleys 
protect him, I thought that the reason he stayed with his aunt and 
uncle was because of blood protection.  

-Mo