I've no idea really. My mother-in-law always said she was 1/4 cherokee so I've looked at the tests offered thru Ancestry.com, for my husband. THey're supposed to be reputable.
Have you tried the Dawes List? I hope I spelled that right. What makes mine so hard is that she was an orphan and was raised by a white family. I have a photo of her and her daughters. I think the son might be on it too.