Whose DNA Should You Trace?

Used with permission from Rootsweb Review

When analyzing DNA for genealogical purposes, it’s important to look at all of your ancestral names.


As discussed a few months ago by columnist Joan Young, in DNA and Genealogy – Beyond the Paper Trail (RootsWeb Review 9 Dec. 2009, Vol. 12, No. 12), DNA tests reports on direct pedigree lines, e.g., from father to son to son, or from mother to daughter to daughter, etc.

There is no cross-over between mtDNA and Y-DNA, so your immediate family members can only be tested for these two lines.

If you are looking for other ancestry – say, for example, your deceased father’s father’s mother’s markers, you can still determine them. Find someone who meets a direct descendancy criteria; this would be through a mother to son (grandfather) or mother to daughter to daughter(great aunt’s daughter) relationship.

Female Research
Known as mitochondrial or mtDNA, women inherit markers from their mothers, but not from fathers. The mitochrondion occurs in the cytoplasm of the cell, as opposed to the nucleus, and typically changes slowly from generation to generation. This is why researchers have determined that there is a “Mitochondrial Eve”, a common matrilineal (female) ancestor, from whom we all descend.

Male Research
Through the direct patrilineal lineage, we theoretically descend from “Y Chromosome Adam”, although the measurements for time periods are eons apart.

The reason for this is that men test their direct male lineage through Y-DNA, as they share a Y chromosome with their fathers (contained in the nucleus of the cell, as opposed to the egg that supplies the mtDNA). In the case of the paternal test, a haplotype is determined, based upon Y chromosome patterns which are distinctive and easily identifiable. Men also inherit mtDNA from their mothers, which is why they are logical test subjects for extended DNA testing.

Another advantage for testing men, is that unless there were an adoption or legal name change, a son would share a surname with his father, unlike women, who unless they had not married (or coincidentally a father-son combination had married women with the same surname), the family name would change at every generation.

Who should get tested?
To solve brick walls, consider testing,

1. Elderly male relatives, and a male at each living generation, to take an extended maternal and paternal test of at least the basic markers.
2. Any female from a unique and direct mitochondrial line to take a basic maternal test.

In my family, the mitochondrial line traces 7-generations to immigrants from Ireland. Several 32 marker tests have been submitted, and two matches of interest have surfaced. One is a 3rd generation American female of Irish descent, and the other is a male, confident of 5-generations of research on his mother’s side. So far, we have not determined the common thread, but we do know that, in all likelihood
The female match indicates the common ancestor is probably at the 8th generation or earlier.
The male match may (and most probably does) share ancestry with the immigrant family, although the common link could be earlier.
Few changes in mtDNA (known as mutations) have occurred from generation to generation.
Without DNA testing, we would not have the opportunity to collaborate.

Another ancestral family line came from Holland. We know the immigrant arrived in America in the mid to late 1700s, but little else. I am urging my male cousins, who share this surname, to take the paternal test, with the hope that a European match will surface.

Follow these charts to see whose DNA test would be the most beneficial for your purposes.

Follow along the colored lines to see the direct mtDNA connections. (Other mtDNA connections are noted by different colored lines and circles.) The Y DNA connections are noted by the color of the male’s box.

Whose DNA do you want? Who can be tested?

Your own…………You, a son or a daughter
Your father………Your father, your paternal grandfather (father’s father only), your brother or your brother’s sons (nephews)
Your mother………You, your brother, your sister, your mother, your mother’s brother (uncle), your maternal grandmother (mother’s mother only), your mother’s sister (aunt), your 1st cousins who are children of your mother’s sister or 2nd cousins via your mother’s sister (assuming they are her daughter’s daughters)
Your mother and father (at same time)…..Yourself, if you are male, or any of your full biological brothers
Paternal grandmother (father’s mother)…..Your father, his brother (paternal uncle), his sister (paternal aunt), the female children of his sister or the female grandchildren of his sister (assuming they are daughter’s daughters)
Paternal grandfather (father’s father)…..Your son, your father, paternal grandfather (himself), your father’s brother (paternal uncle), your brother’s son (nephew) or any male descendant that traces through the male line only.
Paternal grandmother and grandfather (at same time)…..Your father or his brother (paternal uncle)
Maternal grandmother (mother’s mother)…..You, your mother, maternal grandmother or your mother’s brother (maternal uncle)
Maternal grandfather (mother’s father)…..Your uncle, your uncle’s sons (nephews) or paternal grandfather (mother’s father)

Services which test and gather DNA results for genealogical purposes are:




RootsWeb articles of interest:

FamilyHart DNA Projects (Pennsylvania Dutch Families) by Don & Jeanine Hartman
Lost Colony Research Group (Successfully Using Autosomal Testing in Conjunction with Mitochondrial and Y-Line) by Roberta Estes
Mayflower DNA Projects (Canadian Society of Mayflower Descendants) by Susan E. Roser

Previously published in RootsWeb Review: 14 July 2010, Vol. 13, No. 7

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