Genetic Genealogy

Genetic Genealogy: Getting Started

Have you been thinking about taking a DNA test, and don't know where to start or which test to select? Are your parents elderly and you want to make sure you get a DNA sample? Is there only one male left in the direct male line of your family tree? Have you encountered a brick wall in your genealogy research, and don't know what to do next?

Getting started with DNA testing for genealogy is not any more difficult that the various records you have learned about as you have pursued your family history research. A science background is not necessary. This getting started guide covers the different DNA tests available, and will help you select a test.

There are two types of DNA tests available for genealogy: Y DNA Tests and mtDNA Tests. The Y DNA tests are only available for males, since this test involves testing a small portion of the Y chromosome, which is passed from father to son. Males have both an X and a Y chromosome. They receive the X chromosome from their mother, and the Y chromosome from their father. Females have two X chromosomes, one each from their father and mother. Testing Y DNA provides information about the direct male line, which would be the father, his father, his father, and so forth, back in time. Scientists have discovered that a small portion of the Y chromosome is passed from father to son, virtually unchanged. Therefore, if a father and son are tested, their results would usually match.

If two cousins are tested, who have the same grandfather, their results would match or be a close match. By comparing the result from a Y DNA test of two males, you can determine if they are related and approximately when the common ancestor occurred. The locations tested on the Y chromosome for the Y DNA test are called Markers.

There are 3 versions of the Y DNA test available:
Y-DNA12 tests 12 Markers
Y-DNA25 tests 25 Markers
Y-DNA37 tests 37 Markers
The 25 Marker test includes the Markers that are tested in the 12 Marker test.
The 37 Marker test includes the Markers tested in the 25 Marker test.

If a person starts with the 12 Marker test, they can later upgrade to either the 25 Marker test or the 37 Marker tests. The 25 Marker test can also be upgraded to 37 Markers. Selecting the number of Markers to test is primarily a budget consideration. More Markers provide more information. More Markers will also provide more accuracy in the estimated time frame for the common ancestor. In addition, more Markers will eliminate matches that aren't relevant in a genealogy time frame.

The 12 Marker test is best at proving that two males do not have a common ancestor in a genealogical time frame. For all other situations, the 25 Marker or 37 Marker test is recommended. The additional information from the 37 Marker test far exceeds the incremental cost. When the budget is available, select the 37 Marker test. In most cases, those who start with the 12 Marker test or 25 Marker test typically upgrade later. You can save on your cost of testing by selecting the 37 Marker test initially. Y DNA testing has a wide range of applications, because the Y chromosome typically follows surnames.

In addition, the Y DNA test can resolve a broad spectrum of problems, and provides information about the direct male line. Y DNA testing is used in Surname Projects. Surname Projects involve testing one or two males from each identified. Line or family tree of a surname, to determine which Lines are related, and therefore have a common ancestor. Surname Projects can also identify the number of origins for a Surname.

In addition, Surname Projects often provide clues for further family history research and locations for research, as well as save people research time with these clues. Both males and females inherit mtDNA from their mothers. Testing mtDNA provides information about the direct female line of the person, which would be their mother, their mother’s mother, and so forth. mtDNA testing provides information about the origin of your direct female ancestral line.

The result of the mtDNA test would tell you which of the "Daughters of Eve" was your ancestor. There are situations where mtDNA testing can also be applied to your genealogy research. An example of utilizing mtDNA testing for genealogy would be where an ancestor had two wives, and multiple daughters, and you want to determine which daughters had which mother. In this case, you would need to find direct descent female descendents of the daughters, and test them. Lets assume that Daughter 1 is documented with Mother A, and Daughter 4 is documented with Mother B. You are uncertain of the mother for Daughters 2 and 3.

You would find female descendents of the daughters, in the direct female line, and test 1 descendent of each of the 4 daughters. The descendents of Daughter 1 and Daughter 4 should have different results, and depending on which of these results the descendents of Daughter 2 and 3 match, tells you who the mother was of Daughters 2 and 3. The mtDNA test is available in 2 versions. These tests are called: mtDNA mtDNA Plus The test called mtDNA provides a result for the region of mtDNA called HVR1.

The test called mtDNA Plus tests two regions of mtDNA-- HVR1 and HVR2. If you want to find mtDNA matches in a genealogical time frame, select the mtDNA Plus test. Anyone with an understanding of family history research can utilize DNA testing. It isn't necessary to have a scientific background. The few scientific terms you will encounter will be explained. It is easy to get started. Typically, you would want to start with a test of your direct male line and your direct female line.

If you are female, you would need your father or brother or other close male relative to participate for the Y DNA test to represent your direct male line. You can check at Family Tree DNA to see if there is a Surname Project established for your direct male Line. You can perform a search by clicking on the link below: http://www.familytreeDNA.com/surname.asp If you find a Surname Project for your direct male line, order your DNA tests as a member of this Surname Project.

The Group Administrator will provide you with assistance in interpreting your results. In addition, telephone and email support and consultation is available from Family Tree DNA. If you don't find a Surname Project, to order a Y DNA and/or mtDNA test: http://www.familytreeDNA.com/products.html DNA testing is the most powerful tool to ever become available to genealogists. For those who are new to DNA testing for family history, it can seem overwhelming and technical. Genetic Genealogy is not any more complicated than learning about the various records available that may contain information about your ancestors. The easiest way to learn is to take a DNA test.

Understanding your Results:

Y DNA Mutations When Y DNA results show several mutations in a family tree, this may indicate a potential problem with the family history research, and this situation warrants investigation. Mutations are random events. Mutations are estimated by the scientists to occur every 500 generations per Marker.

When there appears to be a high level of mutations in a family tree, the situation should be thoroughly investigated. One or more mistaken connections to your family tree will typically result in a higher than expected mutation rate. A mistaken connection would be where a branch was connected to the family tree in error. This situation can easily occur as your research moves back in time, and the documentary evidence is weak, insufficient, or circumstantial evidence is used. Often, as the family tree goes back further in time, it is more and more difficult to find adequate genealogy evidence to make connections.

Connections are sometimes made based on insufficient evidence, such as a person with the same surname being in the same location. DNA testing will often uncover these mistaken connections. For example, consider two families residing in Colonial South Carolina with the same last name. It would be easy, though not necessarily accurate, to assume that they are related. To illustrate the situation, we have a family tree that has been traced back to a father, John, and his 6 sons. The sons are Thomas, William, Stephen, George, James and Robert. A descendent of Thomas and Robert participated, and took a 37 Marker Y DNA test. The result was a 34/37 match, or a genetic distance of 3. The common ancestor, John, was born about 1726.

If the family history researcher stops at this point, they will never uncover the true situation. Further investigation and testing is recommended. It is recommended that additional participants be tested to determine the ancestral result, and to identify the source of each mutation. If in doubt as to whether to investigate a situation, let's take a quick look at FTDNATiP.

For the above two participants, FTDNATiP shows the following:
100 years 12.41%
200 years 48.13%
300 years 77.07%
400 years 91.57%
500 years 97.25%
600 years 99.18%

The common ancestor occurred in about 1726, or about 275 years ago. According to the results from FTDNATiP, we aren't even in the 90 plus probability range in the 1700's. FTDNATiP is indicating that the situation needs further investigation. We then enter into FTDNATiP the genealogy evidence that the common ancestor did not occur in the last 9 generations.

The revised report is shown below.

225-325 years 55.80%
425 years 83.74%
525 years 94.71%
625 years 98.42%
725 years 99.55%
825 years 99.88%

The probability of the common ancestor has decreased for our time period of 275 years ago. Investigation of the situation is definitely required. A descendent of each of the other 4 sons of John were then tested. There are now 6 results, one result representing each son of John. Four participants are a 37/37 match, one participant is a 36/37 match, and the other participant is a 34/37 match. The result where the 4 participants are a 37/37 match is the ancestral result. Therefore, the additional testing easily identified the ancestral result. The participant with the 36/37 match had one mutation.

It would be possible to determine the source of the mutation for this participant by testing other descendents of the son George. To select a participant to test to determine when the mutation occurred, examine the branch of the tree for the son George. The objective is to find a direct male descendent who comes off the branch half way from George to the participant. Testing this person will tell you if the mutation occurred before or after this juncture. If the new participant has the mutation, the mutation occurred before the juncture where his branch connects to the tree of George's descendents.

If the new participant doesn't have the mutation, the mutation occurred after the generation where his branch connects. This process can be repeated until the source of the mutation is identified, which is also known as resolving the mutation. The next item to consider is the participant who has a genetic distance of 3, or is a 34/37 match with the other 4 descendents. This result indicates that there is a problem that needs investigation. The participant whose result has 3 mutations is a descendent of the son Robert.

The first step would be to test another descendent of Robert, by a different son of Robert. Robert had 3 sons, Thomas, William, and Richard. The initial participant was from the son Thomas. A participant who descended from either Richard or William would be tested. A descendent of Richard was found and participated. His result was a 37/37 match to the result of the other participant from Robert's branch. Therefore, this participant was also a 34/37 match to 4 participants representing the other sons of John. To summarize, at this point in the testing, the results are: 4 participants who are a 37/37 match to each other, each representing a son of John; 1 participant who is a 36/37 match to the above group; and 2 participants who are a 37/37 match to each other and a 34/37 match to the group of 4

The evidence is overwhelming. Robert could not be a son of John, and there is an erroneous connection in the family tree. The DNA evidence has identified the ancestral result for Robert, as having 3 mutations when compared to the ancestral result for John, who is assumed to be his father. This assumption is incorrect. The DNA evidence shows that Robert and John are distantly related, perhaps in the time frame of 1300-1500. It is probably just a coincidence that they are in the same geographic area in the 1700's. Investigating mutations is an important step, both to determine the ancestral result, and to investigate potential mistaken connections.

It may be disappointing to find an mistaken connection in your family tree. Finding and correcting a mistaken connection is better than passing down to future generations a family tree with errors. For further reading, see the following articles:

Interpreting Results: The Ancestral Result http://www.familytreeDNA.com/facts_genes.asp?act=show&nk=2.9 Understanding Your Results:

The Lab, Mutations, or Research Problem? http://www.familytreeDNA.com/facts_genes.asp?act=show&nk=2.3 Understanding Your Results:

Time to the Common Ancestor http://www.familytreeDNA.com/facts_genes.asp?act=show&nk=3.7

Interpreting Results: Comparing Lines http://www.familytreeDNA.com/facts_genes.asp?act=show&nk=2.10

Understanding Your Results: Are We Related? http://www.familytreeDNA.com/facts_genes.asp?act=show&nk=2.6