There are 3 main types of DNA testing used for genealogy: autosomal, mitochondrial (mtDNA), paternal yDNA. Each are great ways to find out information about yourself, but the collected data can lead you in multiple directions. Here I will try to briefly explain the differences.
yDNA – Paternal Line
First thing to know about this type of test is that it is only available to males. This test requires examination of the Y chromosome which only exists in males. However, if you are a woman there is still some hope for you. You can do the test on your brother, father, paternal uncles, or grandfather and the results will be the same. yDNA has been passed unchanged through your paternal male ancestors on your family tree for thousands of years, and due to this fact genealogists are able to use this information to determine where in the world your earliest ancestors lived.
For black people who are the descendants of slaves, using the paternal line when looking for their earliest male African ancestor has a lower rate of success than using your maternal line. According to AfricanAncestry.com paternal DNA test results in African ancestry 75% of the time while mitochondrial DNA tests result in African ancestry 92% of the time. Why is this? Sadly, it is because most white slave owners and overseers raped their female slaves. President of AfricanAncestry.com Dr. Gina Paige gives further explanation about this in the video below.
Mitochondrial DNA (mtDNA)– Maternal Line
As mentioned above there is also the mtDNA test. An unchanged portion of your Mitochondrial DNA is inherited from your mother, who in tern inherited from her mother and so on. This portion of DNA has also been passed down for thousands of years, just like yDNA on your paternal side. However, this test is open to both men and woman and is used find your earliest living maternal ancestor.
As you can see the two previous tests miss out on everyone in the middle portion of your family tree. This where autosomal DNA testing comes in. This is the newest type of test and it covers everyone in your family tree going back around 5 generations and therefore picks up on all the people that were missed in the other two tests. With these results companies can compare the various portions of your DNA with others in their databases to determine what regions in the world your ancestors originated from and provide you with the percentage of DNA that you have that originates from those regions.
Personally, I’ve only done the autosomal DNA test, but hope to do both and mitochondrial and yDna test at some time in the future. As you have seen not all of the 3 types of DNA testing used for genealogy may apply to you, however I hope that this brief post helps if you are considering taking a test.