I don't know much about P's family.

What's Tyka's story? Little sister? Big sister? Half sister?

An artist herself?

I know next to nothing about her, but one of the songs on her MySpace is hot. "Beau-Tay"...

She's his only sibling who shares both parents with him. (Matty/John) ane she currently sings gospel music.
She had a pretty tough life with drugs and all that and her bro paid for her rehab eventually.

She is Prince's natural sister born in 1960, according to DMSR she was named after a TV show called The Tika. She released an album in 1988 called Royal Blue which flopped having marginal talent. She has weight and drug issues most her life and Prince is virtually estranged from her, like most of his family.