by Gary N. Willis
Rapidly mutating DNA markers can be extremely helpful for genetic genealogists. These mutations can identify sublineages that differentiate relatives within only a few generations and can sometimes solve mysteries where there are gaps in the written record. I recently thought I had discovered such a useful mutation. My Y-DNA test results differ from other members of the Maryland Group of the Willis DNA Project at position 439. That location is noted for being rapidly mutating. The genealogical paper trail indicates that seven of the nine members in the Maryland Group descend from Andrew Willis, son of John Willis the immigrant. The other two of us descend from John, Jr., another son of Immigrant John.
If the anomalous marker at 439 originated with John, Jr., it would clearly separate descendants of Andrew from descendants of John. However, the other group member who descends from John, Jr. does not share the anomaly. The mutation must therefore have originated in one of John, Jr.’s descendants rather than John himself. The paper trail shows that the line of the other John, Jr. descendant and my line diverge at Zachariah Willis, a great-great-grandson of Immigrant John. I am descended from Zachariah’s son Henry Fisher Willis, while the other Maryland Group member descends from Zachariah’s son Francis Asbury Willis. The mutation at 439 obviously occurred with Henry Fisher or his descendants, since Francis Asbury’s line lack the mutation.
One of my brother’s test results are identical to mine, including the anomaly. The mutated marker at 439 therefore did not begin with my generation. It must have first occurred with one of three men: our father Noble Sensor Willis, his father Henry Noble Willis, or Henry Noble’s father Henry Fisher Willis. This conclusion is illustrated in the Mutant Marker Chart linked above. Unfortunately, this knowledge has limited value because there are so few male descendants of Henry Fisher. Henry Noble Willis was the only son of Henry Fisher, and Noble Sensor was one of only two sons of Henry Noble. The other son of Henry Noble was Harry McMaster Willis who had no sons. Absent actually digging up a dead relative, it is not possible to determine exactly where the mutation occurred. Thankfully, it is not necessary to be more precise. The remaining males in the entire line of Henry Fisher Willis are the three sons of Noble Sensor (my two brothers and I), plus our five sons and four grandsons. We should all share the mutant marker. No mysteries to be solved there.
Had the mutation occurred with Zachariah rather than further down the line, it would have been extremely useful in identifying kin. Zachariah had a number of sons including some who left the Eastern Shore of Maryland to establish families elsewhere in the country.
(For more information on this family, see “The John Willis Family of Dorchester and Caroline Counties, Maryland” and “The John Willis Family … The Second Generation” recently posted on this site.)
3 thoughts on “The Case of the Unhelpful Mutant Marker”
Way cool. I wish everyone could/would check their DNA. I guess it will never happen due to surprises it might bring. So how many in your family did the DNA testing?
Initially just me. When I noticed the mutated marker recently, I asked my two brothers if one of them would test. Both said yes. We are having jokes about parentage.
I did the “Family Finder” (autosomal DNA) test. So far, it hasn’t helped. The best thing for me so far is in the Rankin line — I talked one of my Rankin cousins into doing the Y-DNA test (for men only, it tests the y-chromosome). Interesting stuff!