|
The information on this page is meant to provide a very simple explanation of your yDNA and mtDNA Ancestry used for genealogical purposes. Scientists estimate that the total amount of yDNA of a man is less than 1% and the total amount of mtDNA in either a man or a woman is less than 1%. It is important to understand that after taking a yDNA and an mtDNA test, the majority of everyone's DNA remains untested and it is called Autosomal DNA, with another 5% of a female's DNA or 2 1/2% of a male's DNA being x-chromosomal DNA. In a man this would mean roughly 95.5% of his DNA is Autosomal and in a woman that figure would be roughly 94%. Click here to find out more about a human's total DNA makeup.
The two basic tests used for genealogy purposes are yDNA tests (male) and mtDNA tests (female). Both tests, the yDNA and the mtDNA, sample a very small amount of your total DNA and as genetic genealogists know, the test most taken is for yDNA. It can show a relationship between two males; genetic cousin is a term that is commonly used. The mtDNA test is less practical for genealogical use because traditionally the female's birth or maiden name changes from generation to generation. With that said, mtDNA still may be used to prove scientifically that two people (male or female) share a common maternal ancestor, although it is more effective at proving two people do not share a common maternal ancestor.
Below is a simplistic chart showing two children, a brother and a sister. In addition to them, their parents, grandparents, great grandparents and gg grandparents are also shown for visualization of their DNA Ancestry. Note how the brother has a two color graphic to show how he carries both yDNA and mtDNA. The brother's sister has a one color graphic; this is to show that she only carries mtDNA.
For the purposes of our Phillips DNA study, a male DNA participant who tests both yDNA and mtDNA will have two EKA's (Earliest Known Ancestors). One will be a paternal ancestor (straight line father's yDNA) and the other a maternal ancestor (straight line mother's mtDNA).
Since women do not have yDNA, a female will only have one EKA that is associated with her DNA test, her maternal ancestor (straight line mother's mtDNA). See the chart below to help visualize the yDNA and mtDNA Ancestry of the two test participants, the previously mentioned brother and sister.
Please note that there are many other lines of DNA that remain untested even if you have tested both your yDNA and your mtDNA. These untested DNA lines are represented below by the circles and boxes that have no interior color, they are your autosomal DNA. Genetic scientists are slowly developing tests that can study and classify your autosomal DNA, but these tests are much more expensive, controversial, complicated and less straight forward than the yDNA test or the mtDNA test.
|
|
|
Ancestry Chart of Inherited Paternal yDNA and Maternal mtDNA
|
|
Simplified Chart showing the less than 1% of yDNA and/or mtDNA in a brother and a sister.
|
As you can see from the graphic above and to the left, a son inherits the yDNA of his father and the mtDNA of his mother. A daughter inherits the mtDNA of her mother but not the yDNA of her father. Because of a male's inheritance of both yDNA and mtDNA, a male may be tested for both his father's yDNA and his mother's mtDNA. A female may only test for her mtDNA because she has no yDNA from her father.
Even though the male may test both yDNA and mtDNA, he cannot pass his mother's mtDNA to his children. However, he will pass down his father's yDNA to his sons. A female will only pass down her mother's mtDNA, whether it be to her sons or her daughters.
|
|
Shown to the right is a children chart of the DNA the brother will pass down to his children and a similar chart for the DNA the sister will pass down to her children.
When the brother starts having children, as stated above, he will pass his father's yDNA on to his sons, who will likewise do so to their sons. Even though he has his mother's mtDNA, he cannot pass her mtDNA on to his daughters. The mother of his children will pass her own mother's mtDNA on to their children, both their sons and their daughters.
When the sister starts having children, she will pass her mother's mtDNA on to her daughters, who will likewise do so to their daughters. She will also pass her mtDNA down to her sons, but as stated above, her sons cannot pass her mtDNA on to their children. She cannot pass down her father's yDNA to her children because she has no yDNA. The father of her children will pass his yDNA to her sons.
|
Simplified Chart showing the less than 1% of yDNA or mtDNA passed down to children from their parents.
|
yLineage and mtLineage
Most genealogists focus on a yDNA Lineage when researching their family. They are commonly written like this:
1. John Phillips b. 1756 VA m. Mary Smith
2. Thomas Phillips b. 1783 TN m. Polly Jones b. 1785
3. Henry Phillips b. 1809 TN m. Sarah Redmond b. 1811 TN
4. John Phillips b. 1831 KY m. 2nd Olivia White b. ca 1846
5. Jacob Phillips b. 1863 m. Hannah Brown b. 1867
....and so on....
An mtDNA Lineage should look like this:
1. Rachael Smith b. 1788 GA m. John White b. 1782 GA
2. Margaret White b. 1806 SC m. Nathanial Green b. 1801 SC
3. Mary Green b. 1831 TX m. Thomas Brown b. 1827 TX
4. Sarah Brown b. 1859 TX m. Mark Jones b. 1851 OK
5. Tempy Jones b. 1890 OK m. William Conner b. 1888 OK
....and so on....
In an mtDNA Lineage, you can see that the surname of the female changes from generation to generation. In the yDNA Lineage, the surname remains the same unless a NPE (non paternal event) takes place. When researching a yLine, it is common to focus on the surname as it is usually constant. For example, when researching John Phillips b. 1756 in VA, one assumes they are looking for a father with the Phillips surname.
To produce a useful mtLineage, it is necessary to avoid the temptation to use a husband's surname as a substitute for the wife's birth name when posting the EKA of a maternal line. Because the surname of a maternal ancestor changed from generation to generation, it is necessary to be more attentive to the maternal line's details.
Suppose it is known that Rachael Smith's mother's name was Elizabeth, but Elizabeth's birth surname is unknown. Perhaps you know that Elizabeth married a John Smith and had a daughter Rachael Smith. You might even know that Elizabeth was b. in 1759 or any other possible piece of information. Unless Elizabeth was a cousin of John Smith, her birth surname probably would not have been Smith. You could report this as Elizabeth mnu (maiden name unknown) b. 1759 m. John Smith, but keep in mind that when someone is researching it is better to have a surname for reference.
|
FAQ Sections 
