Important Concepts to Understand

Number of Ancestors
The number of ancestors in one’s family tree doubles with each generation into the past, following a straightforward progression. For instance, having two parents results in four grandparents, eight great-grandparents, sixteen great-great-grandparents, and so forth. If there are approximately twenty-five years between each generation, then tracing back twenty generations places an ancestor roughly five hundred years in the past, around the early 1500’s. This long ago, the family tree expands to over one million ancestors of that generation. However, it is essential to recognize that this extensive family tree doesn’t necessarily represent one million distinct individuals due to the occurrence of pedigree collapse. Pedigree collapse occurs when distant relatives intermarry or share common ancestors, reducing the number of unique ancestors in the family tree. Furthermore, while the mathematical model of a family tree might suggest a billion slots for individual ancestors at thirty generations back, the reality of overlapping ancestries significantly reduces the number of unique ancestors. This quickly adds up to an impossible number that exceeds the number of people living on Earth. Hence, we of course do not come from everyone on the planet a thousand years ago, but this is why it’s more accurate to feel connections to certain communities and regions of older eras than individual ancestors.

DNA and Genetic Relationship
The amount of DNA received from each ancestor halves with every generation. Children share 50% with each parent and about 25% with each grandparent. However, since DNA is random, a grandchild could also share only 20% from one grandparent and 30% from another. People only share about 12.5% of DNA with great-grandparents, which is the same percentage as with a first cousin. As a personal example, one of my x5 great-grandparents was born in 1785 and I share approximately 0.78% of my DNA with them. That is about the same amount of DNA that is shared among third cousins. On average, 5th cousins share a miniscule amount of DNA, less than 0.005%. So, while it is feasible to say that every person of European ancestry is a descendant of King Charlemagne, it is unrealistic to hold the idea that they are all also “related” and share DNA today. In sum, DNA becomes too washed out to claim a strong genetic relationship to an individual who lived even 400 years ago, much less ages into the past.

Photos of Ancestors
Photography was invented in the 1820’s; however, it’s important to note that photographs of ancestors are not typically found until at least the 1850’s. This delay can be attributed to the fact that early photography technology, which emerged in the 1830’s, initially struggled to capture portraits of people and other living subjects effectively. By the mid-to-late 1840’s, daguerreotype photography became more accessible in the United States, though it remained relatively expensive for the average rural family.

Nineteenth photos are often misidentified in terms of both the individuals depicted and the era in which they were taken. For additional insights into correctly identifying and categorizing family photos, I recommend exploring the historic photograph collection.

Ancient Genealogy
The goal of tracing and documenting ancestry before the American Revolution can be exceptionally challenging. This challenge arises not from a lack of skill but rather from the general absence of reliable record-keeping systems during that era or, regrettably, the loss of entire courthouses and historical documents in the past.

For most common rural settlers who did not hold public office or wield notable influence in their regions, the documentation of Colonial-era ancestry is often sparse. Claiming a well-documented pedigree that stretches back prior to the 1600’s is usually unrealistic. While not impossible, dedicating excessive time to researching individual ancestors and attempting to reach the Medieval period may not yield reliable results and may not be the most efficient use of one’s genealogical efforts.

In genealogy research, substantial pre-Revolutionary documentation is a rarity, and it’s advisable to prioritize building a strong foundation in more recent generations. This approach helps prevent the loss of entire branches of one’s pedigree due to incorrect or unreliable information. After all, the goal is to preserve and expand the family tree, and it can be disheartening to cut off branches once they’ve grown.

12 Genealogy Research Tips

Related Links