One of the biggest things to understand is that DNA testing in any form is not the Holy Grail of Genealogy research. You will still have to go through the steps of confirming the data by doing your documented genealogy research. In this blog I will outline some of the other limitations of the research.
The mt and y testing are only good for females and males respectively. Identifiers in DNA testing identify information for either the female or male moving backwards. Not both. Only two grandparents apply to this testing out of the eight that you have. The information is for your father's paternal grandfather and your mother's maternal grandmother. In order to get a broader representation of your families DNA you will have to recruit uncles, aunts and cousins to participate in the study to complete the DNA of the other six lines. In order for the women to identify her Y chromosome lineage they will have to get their father and brothers tested to learn about the paternal line.
DNA testing is a great and unique tool in genealogy, but it does not give a complete picture. You will still have a lot of gray areas. Working to get a complete DNA picture takes a lot of coordination and a large enough pool of living people that are willing to participate. You will have to way the benefits.
Hopefully this is helping in some small way. Please leave your comments and support my advertisers. Check in tomorrow for more on using DNA in your Genealogy research.