Sorry, day late but hopefully not a dollah short. If there was no root on the hair or if the DNA in the root was too disintegrated to get nuclear DNA, the lab would then do a test on the mitochondrial DNA. Caylee, Casey, Lee, Cindy, and Cindy's mother (for example) all have the exact same mitochondrial DNA. In the case of the females, all of the females in their direct line back thousands of years ago will have the same mtDNA (unless there was a mutation, but that is not likely in any meaningful past). I had my mitochondrial DNA tested and the results were pretty amazing. I'm a green-eyed blonde (compliments of dad), but the original mother to all the females in our line came from the Middle-East or Central China. (My mother had brown eyes and brown hair but I'll spare you the genetics of why her brown eyes didn't trump my dad's blue eyes.)
Lee has the same mitochondrial DNA as his mother, but his children will have the mitochondrial DNA of their mother, which is why the chain of identical mitochondrial DNA holds true for females but not for males. If Cindy has a sister, then all of her sister's children will have that same mitochondrial DNA as well.
So technically, if they did use mitochondrial DNA to test the hair, the only way to tell who it belonged to out of the people mentioned above would be to compare hair color, length, dye process, etc. But since there was the "band of death" on it, that rules out the living sources of the hair in question.
