>To get the paternal, hopefully-African ancestry of Grandpa Bill, I can send in a DNA
>sample of one of the sons of Grandpa Bill's 6 sons. A couple of these grandsons of Bill
>are still living. This includes my mother's brothers, and my cousin/roommate can
>be inclusive since Grandpa Bill is his paternal grandfather's paternal grandfather.
As long as it is male-to-male direct ancestry between Grandpa Bill and ‘cousin/roommate’ his Y-chromosome will match that of Grandpa Bills sons’ sons.
>To get the maternal African ancestry of Grandpa Bill tested, I would have to get the DNA
>sample of a certain descendant of Grandpa Bill's sister, Mary (Mary and Bill shared the
>same mother). Mary only had 2 children: a son, William, and a daughter, Louvenia.
>There are no known descendants of William, but Louvenia had 4 sons and 3 daughters
>(all 7 are deceased). Of those 3 daughters, only one of them (Allie Bell) had children.
>Allie Bell has a living daughter in California, I'm told. So, I will have to locate this 3rd
>cousin to test Grandpa Bill's maternal ancestry. Is this correct?
Yes, that’s correct.
>I've been also thinking about Grandma Sarah Reed's ancestry. She and Grandpa Bill
>had 6 sons and 5 daughters, all deceased. Therefore, the only descendants with her
>mtDNA would be her youngest daughter's children. The youngest daughter was the only
>daughter who had children. She had 11, and only 3 living now - two sons and one
>daughter. Those 3 children's mtDNA would be identical to Grandma Sarah's. Right?
>And their mtDNA would be identical to Grandma Sarah's mother, Polly Partee. Right?
>Grandma Sarah's paternal ancestry is questionable. Grandma Sarah was said to be part
>Indian. Family lore has it that her father, name unknown, was Cherokee. Sarah had
>three brothers. But the problem is, Sarah was her mother's oldest child, and I am not
>sure if Sarah and her brothers shared the same father. I can't even get a test done to
>determine if this Indian ancestry claim is accurate since only men inherits the
>Y-chromosome from their father. Right?
You are right that only men get the Y-chromosome, but you can still find out if there is Native American ancestry. The third type of test, the bio-geographic ancesty or heritage, will tell you percentages of different ancestry from four major historical population groups:
1. European, 2) Native American, 3) sub-Saharan African, 4) East Asian.
However, this will not pinpoint any specific group or location. See more here: http://www.ancestrybydna.com/