Whether you’re using Ancestry’s new Custom Cluster tool or have simply identified an important DNA match, determining how a match fits into your family tree is why we review matches. Since the publication of my Chutes & Ladders blog post, I’ve received several requests to elaborate on the concept of DNA Laddering.
I am pleased to announce the publication of my latest MyFamilyPattern YouTube Learning Module on DNA Laddering, which includes several “live” examples for how a DNA Ladder is constructed and used to identify an unknown match.
DNA Laddering
For an unknown match, DNA Laddering is a process of quickly reviewing the family trees of its closely related shared matches progressing backwards one generation at a time. Akin to the rungs of a ladder, DNA Laddering permits you to incrementally trace the unknown match’s genetic path back through the unknown match’s specific parent or grandparent line to a common ancestor among its closely related matches.
DNA Laddering uses Ancestry’s Pro Tools’ Enhanced Shared Matches to view how the unknown match is related to its other shared matches. Pro Tools is an extra monthly charge. MyHeritage provides the same tool at no extra cost as part of its DNA match reviewing platform. However, I prefer performing DNA Laddering on Ancestry because of its larger database of matches with publicly available family trees.
While I describe DNA Laddering in the YouTube learning module and in the earlier Chutes & Ladders post, DNA Laddering in brief is about two tasks. First, a ladder must be constructed for the unknown match where its matches are sorted to be more closely related to it rather than the DNA tester. A good ladder is present when the unknown match has at least one first cousin, second cousin, and third cousin shared match with family trees that are sufficiently constructed out to the grandparent, great grandparent, and 2x great grandparent level, respectively. This permits you to follow the DNA path backwards through the generations one grandparent level at a time (see the above image).
Once a good ladder is available, the second step is to rapidly review the closely shared DNA matches one generation or cousin level at a time, i.e., one rung of the ladder at a time. Rapid reviewing relies more on memory than on detailed note taking. The idea is to observe end of line ancestor surnames and birth locations for the unknown match and quickly compare it to the first cousin match on the next rung. At this stage, one should be able to narrow down the ancestral line of interest to one side or one grandparent line in the unknown match’s family tree. Rapid reviewing without heavy note taking minimizes the chances in progressing down rabbit holes of unnecessary research and focuses your interest on specific ancestral lines of your matches.
The process continues by moving to the second cousin, third cousin, and so forth until you connect the unknown match into your family tree. If you cannot connect the match into your tree but you identify a group of the shared matches who all descend from a common progenitor through multiple child lines, then you’ve identified an unlinked family cluster. While not as satisfying as linking the group of matches to a known ancestor, unlinked family clusters provide additional genetic and documentary research opportunities to discover the next generation or more further back for your ancestor of interest.
Once you identify the common progenitor of a group of shared matches or the match’s ancestral line where the common DNA was likely inherited, now you actively take notes and perform focused research. The goal now is to determine how the unlinked family cluster fits into your family tree.
Climbing the DNA Ladder one run or generation at a time is the ideal method to climb toward identifying an unknown match especially when the shared matches have relatively good family trees. Skipping a single run is ok if good matches are not available at a cousin rung, but skipping too many rungs hinders the easy identification of the genetic path for the shared ancestry between the unknown match and its closely related matches. In the DNA Laddering YouTube learning module, I discuss how to construct a better ladder if a good ladder is not available.
YouTube Channel
Be sure to check out my YouTube Channel for learning modules on other topics like DNA research strategies such as EGGOS Search Strategy for strategic family tree triangulation and when to use Small DNA Matches in your research. Watch the DNA Laddering learning module here.