My master's thesis at Cornell was actually in the field of the history of science and focused on the Peking Man paleontological digs of the 1920s and 1930s. (If you would like you can find a copy of it here: https://ecommons.cornell.edu/handle/1813/8399 It's free to read and download. I'm very proud of it.)
For this reason, I have a strong background and interest in the history of science in the areas of evolution, paleontology, and related fields. At one point, while working on the thesis while struggling to understand the newer sub-field of DNA evidence and its use in understanding human history and evolutionary science, I picked up a book on this area of science aimed at a general audience entitled, "Mapping Human History -Genes, Race, and Our Common origins." Written by Steve Olsen, a science journalist, the work has a lot of interesting information in it although speaking as a historian, at times I felt it seemed determined to conform to current political thought. (It's been years since I have read the book, but I remember feeling at times that the author seemed absolutely determined to dismiss the concept of race among humans. Is there such a thing as race? Race is a classification system and like all classification systems it has fuzzy boundaries. Does it measure real differences? Sometimes. Has it been misused? Of course, history shows this. Does it have a usefulness? Sometimes. Some races of people are more prone to some health problems than others. Is racism a real problem in our society? Of course, but simply making blanket assertions that race does not exist is going to do little to end the problem in my opinion.)
But that's not my topic for today. Instead I am going to share Olsen's interesting views on genealogy, human intermingling, and human heredity.
Many people like to talk about their genealogy and prominent ancestors. If they are American, a society where one is not supposed to consider oneself better than other do to one's ancestry, they sometimes just drop ancestors casually, assuring those listening that it's "just interesting" and "not important." While travelling in Asia, I met someone, an American my age, three times and enjoyed each encounter very much. However, at some point during each encounter, each of these three times, he made a mention, always assuring me it was unimportant, that among his ancestors was Daniel Boone.
But is this uncommon? And even if it is, what are the chances that this is really true? That these famous people really are their ancestors?
Let's take these questions in order. First, is it uncommon to have a famous ancestor?
According to Olsen (page 46 in this book), Joseph Chang, a Yale statistician, has looked at issues of ancestry and inter-mingling and come to an interesting conclusion. If we look at all the people who lived 800 years ago, then according to Olsen's reporting of Chang, humanity of the time falls into two categories. The first are people who had ancestors who survived to reproduce offspring who in turn had offspring and so on for a few generations or so. In other words, the people who have descendants who are still around today.
The second are people who either did not reproduce or whose children did not reproduce or whose descent line, somewhere down the line, got cut off. In other words, people who do not have descendants who are still around today. (Chang wrote about this in a paper called "Recent Common Ancestors of All Present Day Individuals" which appeared in a journal called Advances in Applied Probability on pages 1002-1026 of volume 31 in the year 1999. I confess I haven't read it, but it's probably quite interesting. Seriously.)
Now, interestingly enough, Chang argues that while people in the second category, no matter how famous, are not anyone's ancestor, statistically speaking, people in the first category, statistically speaking, are quite likely to be an ancestor of everyone alive today. Which despite the fact that people don't actually marry and intermarry between groups based on statistical likelihood is quite interesting.
In other words, if someone should come to you and say, for example, "I have a famous ancestor, King Bobo, the Leper, of East Westphalia" (or some other king of some other place) and should he or she have lived 800 years ago or more, you are within your rights to reply with an answer like "No sh*t? Really? Chances are he's my ancestor too." And, statistically speaking, you are within your rights.
Really. Go ahead. Feel free.
Which brings us to interesting situation number two, again according to Olsen and this book (on page 48).
When we look at geneaology, few people consider, or at least discuss, the issue of false paternity. In other words, there is a percentage of people whose father is not who they think their father is. In some cases, their legal father may not only not be their biological father, but he may have no idea that he is not their biological father. Statistically, yes, we are again speaking statistically, this does happen but nobody knows how often. (In fact, this issue played a big part in the plot of the second issue ever made of the TV show House, a show about an eccentric, angry doctor who is able to diagnose medical cases that most find undiagnosable. The episode was called, for obvious reasons, Paternity )
In other cases, a person might not just be confused as to who his or her biological father is but also who his or her biological mother is. In other words, he or she might be raised by two people who are not his or her biological parents, and have no idea at all that this is the case. There are many reasons why this might happen, some of them quite well intentioned. Adoption is one such case, of course, or simply taking an abandoned or orphaned infant and choosing not to tell them that they are not a biological child (although, statistically speaking, they did have common ancestors 800 years or so ago, as described above). Olsen also mentions that there might be cases such as an accidental or even intentional swap of infants in a hospital somewhere where neither parent or child is aware of their real (or un-real) connection.
Olsen states that medical students are taught that between 5 and 10 percent of people do not have the genetics they believe they have because of issues of non-paternity. He also states that non-published data from genetic studies supports this, although, of course, this is and would be impossible to confirm without finding the non-specified, unpublished studies.
Interestingly, Olsen states that this is one way in which ethnic groups and races mix without people being aware of it.
For our purposes here, what's important is to remember, one, geneaologies are not always 100% accurate. Now this can work both ways, so, for instance, if you we go back 8 generations, you would have 2 to the 8th power or 256 ancestors, going one more generation, assuming no one has married cousins at any point in the process, something quite common in most of history, you'd have 512 ancestors, and at 10 generations (or 200 years estimated) it would be 1,024 ancestors. According to Olsen, probably 5% of these or about 51 of them are not who the record says. But that could work both ways, of course, if one is interested in determining your descent from a particular individual. That individual, he or she, might be connected to you through some secret path, perhaps one involving a mailman, a milkman, or a deliveryman (or milkmaid or mail woman or other person. Who knows?) and, two, beyond a certain point in history, if someone lived in the region where you had ancestors (which could be a much wider region than you think) then that person, if they have living descendants, is like to be to be your ancestor too.
