the only way lyle wouldn't be her brother is if the DNA sample was messed with before jarod tested it.
I wouldn't put it past the Centre. I still say they lied about Angelo being Parker's brother (plz tell me I remember right, and that is what it turned out to be).
When it comes to Ms Parker, there are a lot of lies. I wouldn't be suprised to find out she's a Pretender, too, and she's been pretending to be Mr Parker's daughter this whole time.