Relatively Speaking Blog

During the long cold winter months, I nestled by my computer tending to my family tree. For the new year I renewed my membership with ancestry.com and focused mainly on my Ludwick family, adding many new relatives. Every now and then I would pick up a lingering puzzle on another line to see if I had any new insights. I reviewed ancestry hints over and over, but not much turned up. I kept wondering what I could do to improve my research and solve some of these riddles. Luckily for me, the answer came at the end of February.

Last month Family Search, a free online genealogy service, hosted a conference called Roots Tech. Like many conferences in the current state of Covid, it was a free virtual event. Roots Tech hosted over 1500 sessions in nine categories that covered topics from basic genealogy to advanced tools and tips for solving family research problems. The sessions, varying in length from 15 minutes to under an hour, were recorded and remain available for viewing on the Roots Tech website.

The category of DNA was one in which I was most interested. I have read some books and gained an understanding of the different types of tests and the companies that provide them. I also took a basic class on DNA five years ago to learn how DNA could help with genealogy. But with new advances in the technology surrounding DNA tests, I wanted to expand my knowledge of how it can help me discover new ancestors in my family tree, so I chose several DNA related talks.

The DNA sessions typically begin with a review of some basic concepts. Humans have 23 pairs of chromosomes, receiving one from each parent. The last pair is often referred to as the sex chromosome since it determines gender. A female has two X chromosomes, one from each parent, but a male has one X chromosome from his mother and a Y chromosome from his father. The chromosomes, which contain genetic material, can predict a relationship between two people by comparing the number and the length of the segments they share. The more segments in common the more closely related the two are.

“Reconstructing a Parent’s DNA” was a session title that caught my attention. In my class five years ago, my instructor mentioned that researchers were studying the possibility of constructing an ancestor’s DNA from his or her descendants. This thought stayed with me, especially the idea that if you could create the DNA for a great grandparent, then could that DNA sequence be read to learn physical qualities like facial structure and graph a possible image of that ancestor? Now here was a presentation on a process that not long ago was just a concept.

This was the first session I watched during the conference weekend. A couple of websites are in the beginning stages of performing this type of service, but you need to have DNA from one of your parents, as well as DNA from your siblings. When there are many siblings, the accuracy rate of reconstructing the parents DNA increases to over 99% in test studies. Results with only a few siblings tend to be about 80% accurate, since some segments of DNA might not have been inherited by any of the children.

It was indicated the possibility exists to construct DNA for a common ancestor by comparing the DNA from known cousins, although no company was mentioned as doing this currently. Some segments might not get passed down, so the DNA sequence for the ancestor could be incomplete. Although it is not useful for me at the present, I was excited to see what has developed in a short time. In another five years, perhaps this will be more common, and I can only imagine how this might assist with tracing a family line further back when a paper trail is not available.

Of immediate interest to me is how I can apply DNA to break through brick walls in my tree, so I viewed a session that discussed how the X chromosome could help in genealogy research. Autosomal testing is the type most people get when using companies like ancestry.com. It compares all the chromosomes and determines possible relationship matches gong back 4-8 generations. Although the X chromosome is part of the autosomal test, only Family Tree DNA and 23andMe are testing companies that provide tools for “X” analysis.

Whereas other chromosomes can be inherited from any ancestors, the 23rd chromosomes have a specific and slightly more traceable inheritance path, especially for men since a man’s X chromosome is passed down exclusively by his mother. Consider that a person has 128 fifth great grandparents. For a male only 21 of those ancestors could have passed down genetic data on the X chromosome; for a female it is 34 of her fifth great grandparents. Reviewing inheritance patterns and using triangulation for the X chromosome between distant cousins could aid in identifying a common female ancestor several generations back. This is something I hope to be able to apply to my maternal Moser and Blackson lines.

Triangulation, as explained in another session, is the process of comparing genetic similarities between three or more individuals. When a group of people match on the same chromosome along a similar segment, this confirms the group shares a common ancestral line. Companies like 23andMe, GedMatch, My Heritage, and Family Tree DNA all have their own tools for calculating and displaying triangulation.

By finding a successful triangulation between known matches, it can be extended to identify unknown matches. For instance, if several people share an identical segment along chromosome 6, finding someone who shares the same segment on that chromosome would indicate they have a similar ancestor with the group, although genealogy research might be needed to confirm which one. Also with triangulation, if you have confirmed distant cousins, identifying what chromosomes you all have in common can indicate what genetic information was inherited from your mutual ancestor.

The last DNA session I have watched to date was on Endogamy. This term applies to a small population that married within its community over an extended period of time. It occurs for religious reasons, like with Ashkenazi Jews, or due to geographical isolation, such as with native Hawaiians. In extreme endogamy, a person might be descended from the same ancestor in multiple ways. Using DNA becomes challenging since matches could have various relationships and appear to be more closely related than what they are.

To get a sense of endogamy, imagine a linear pedigree chart that displays 2 parents, four grandparents, doubling each generation back with a typical person having 32 distinct third great grandparents. When third cousins marry, their children will have only 30 distinct ancestors. The pedigree chart shrinks with one pair of ancestors now having two lines descending from the couple rather than the usual one; this is called a pedigree collapse. Endogamy is pedigree collapse occurring multiple times so that the pedigree chart crosses and twines together, till it looks more like an abstract drawing. In cases of extreme endogamy the tree could contain 20 or less distinct ancestors, instead of 32 at this generational level.

I suspect there might be a small bit of endogamy on my paternal side. For many years my ancestors lived in a Pennsylvania rural community bordering Lycoming and Sullivan counties. Some of my ancestor’s siblings are related to me in several ways on different lines. For instance, my great grand aunt Rebecca Brown married Jacob Rider my third great grand uncle. Their children are both my first cousin twice removed, as well as my first cousin four times removed. When reviewing DNA matches it is often impossible to determine whether the match is related on my grandfather or grandmother’s side since they all appear to be related to each other. Whenever I am able to trace my tree back another generation or two, I would not be surprised if I find some pedigree collapse with my ancestors.

Other sessions I viewed were more general. I learned a few tips about searching and navigating the Family Search site for finding family information. Family search provides free access to its documents; you just need to create an account. One session focused on the site’s book collection that contains printed genealogies by other researchers and county histories that feature biographies on prominent residents. Many of these are available online as Family Search is digitizing all of its records, which include census enumerations, marriage licenses, land transfers, estate and probate accounts, and records from other countries. This site is a valuable resource for researching one’s family tree.

For anyone interested in genealogy, the Roots Tech sessions and the Family Search website are great ways to gather information for genealogy. After watching the handful of the 1500 sessions, I am inspired to continue learning about the available tools for analyzing DNA, resources and tips for locating documentation, and how I can apply these techniques to my own research. Triangulation and X chromosome comparisons are two procedures I will investigate further and explore if there are other sessions on these topics. Using DNA as a guide, along with searching other records, I hope to put into practice what I have learned to track down some of my allusive ancestors.