Limitations of Testing

Y-DNA and mtDNA pass down along exclusively male and female lines. Since each is undiluted by marriage, these types of ethnic DNA testing are highly accurate. The fundamental limitation is that they only represent a small fraction of your total ethnic ancestry.

Go back just four generations and you have 16 great-great grandparents. At that point the Y-DNA and mtDNA tests each represent only 1/16 of your ethnoancestry. You’re totally missing the people in the center of that Pedigree Chart. Go back several more generations and you have thousands of ancestors, each of which contributed to your personal DNA.