Visualizing Challenges to Genetic Genealogy Research Using Leeds and Collins-Leeds Methods

When it comes to genetic genealogy, it’s best to hope that each generation in your family tree was large, with lots of descendants living in countries where DNA testing is popular. Unfortunately, it doesn’t always work out that way. Small families, and families in which many of the distant cousins are living in a place where DNA testing is not as popular (e.g. Poland) make it difficult to find those DNA matches that can lead to breakthroughs in your research. Whether you know, or only suspect, that this is the case for your family, you can visualize the situation using some of the available tools out there, such as Leeds worksheets, and Collins-Leeds matrices.

What is the Leeds Method?

Back in 2018, which is a lifetime ago in the world of genetic genealogy, researcher Dana Leeds described her method for color-coding DNA matches using a spreadsheet, which she developed in order to help a client identify his biological family. Elegant in its simplicity, the Leeds Method took off, and it inspired a number of next-generation automated tools which cluster a tester’s DNA matches based on shared ancestry. Sites which offer autocluster tools include MyHeritage, DNAGedcom, Genetic Affairs, and GEDMatch, and AncestryDNA’s colored-dot grouping tool is also based on this method. With all these automated options available, it’s become a bit passé to create a Leeds Method spreadsheet manually. Nonetheless, I want to share one with you here, because it’s a compact visual aid for illustrating some “structural defects” in my mom’s family tree, and their impact on her DNA match list.

Figure 1 shows a Leeds Method worksheet created from my mother’s list of DNA matches on Ancestry.

Figure 1: Leeds Method worksheet for my mom’s DNA matches on Ancestry. Click image to view larger.

Leeds’ basic goal was to sort a list of DNA matches into four clusters, representing matches who are related to the tester through each of that person’s four grandparents. Individuals to whom we are related through only one of our four grandparents are our second cousins, so second cousins would be ideal test subjects for creating a Leeds worksheet. Thanks to the random nature of DNA inheritance, the amount of DNA shared between any two second cousins can vary, but typically, they share about 200 centiMorgans (cM) DNA, where a cM is the unit used to express genetic distance. (More cM shared = closer genetic relationship.) The exact amount of shared DNA between two second cousins can be as little as 41 cM, and as much as 592 cM, according to data gathered by Blaine Bettinger’s Shared cM Project.

With that in mind, Leeds opted to focus on DNA matches who shared between 90 cM and 400 cM DNA. Using her method, a color is assigned to the first match in the the list who shares between 90–400 cM with the tester, and then that same color is assigned to all the shared matches (or “in common with”) matches. This process is repeated until all the matches who share 90–400 cM have been assigned a color. Ideally, you want to exclude first cousins (1C), and descendants of first cousins (1C1R, 1C2R, etc.), because they will match you on two grandparents, not just one. This can be a little tricky if your family tree is not well-developed, because the amount of DNA shared between two people who are 1C1R, 1C2R, or 1C3R, can fall within that 90–400 cM range. However, the beauty of the Leeds Method is that it works even if you don’t know precisely how you’re related to someone, so having a few “mystery” matches in your worksheet that are 1C1R, etc., shouldn’t throw you off too much.

The 33 matches shown in Figure 1 were culled from my mom’s top 52 matches. Since I do know how most of my mom’s top matches are related to her, I took those first 52 matches and subtracted out all children, grandchildren, first cousins, and their descendants, who would match Mom on more than one grandparent. I removed the names of the DNA matches to protect their privacy, but they’re identified by the documentary relationship (if known), as well as by the amount of shared DNA in both cM and number of shared segments. The next ten columns, labelled 1 through 10, are the result of sorting Mom’s match list according to the Leeds Method. In column 1, the blue bars represent matches to whom Mom is related through one of the ancestors of her maternal grandmother, Veronica (née) Grzesiak. The red bars in column 2 represent matches to whom Mom is related through one of the ancestors of her paternal grandmother, Genevieve (née) Klaus. Columns 3 and 4 represent those matches to whom Mom is related through her paternal grandfathers, John Zazycki (purple bars) and Joseph Zielinski (green bars).

This brings us to the first observation I’d like to make. By looking at those four columns, it’s pretty clear that Mom has substantially more DNA matches who are related to her through the families of her grandmothers (Grzesiak and Klaus, blue and red), than she does through the families of her grandfathers (Zazycki and Zielinski, purple and green). She has exactly one match at this level who is related to her through John Zazycki: a 2C1R who is descended from John’s older sister, Marianna (née Zarzycka) Gruberska. Worse, I have to go all the way down to the level of a 4C2R to find a match that’s related to my mom through her grandfather Joseph Zielinski. The common ancestors between Mom and that match are my 6x-great-grandparents, Stanisław and Urszula Swięcicki, who lived back when there was still a Polish-Lithuanian Commonwealth, and who had already finished having children by the time of the final partition of Poland in 1795. (The story of that DNA match can be found here.) In other words, Mom has few-to-no “close” matches, depending on how you define “close,” who are related to her through either of her grandfathers.

So, what factors cause this phenomenon? In the case of the Zielinski family, my mother’s grandfather was the only one of the ten children in his family to survive long enough to marry and have children. This means that my mother has no second cousins who are related to her through her Zielinski family, and second cousins are what the Leeds Method hopes to exploit when developing initial groupings. The situation with the Zazycki family may be similar. My mother’s Zazycki grandfather, John, was one of eleven children, six of whom (including John) had children. John was the only one of his siblings to immigrate to the U.S., however, and it seems that not many of his siblings’ descendants opted to immigrate, either. Research is ongoing, but thus far it appears that only John’s eldest sister, Marianna Gruberska, had any children who immigrated. Presumably, the descendants of the other Zazycki (or Zarzycki) siblings remained in Poland. It may be that more of those Zarzycki relatives from Poland will start showing up in my DNA match lists, as DNA testing becomes more affordable and more popular among Poles. Time will tell. And If there are cousins in Poland who might be testing their DNA, it’s more likely that they’ll be showing up in DNA databases from MyHeritage and FamilyTree DNA, since those sites are are more popular than Ancestry DNA in Poland. So, I keep checking all the databases regularly, but thus far the situation has been similar in all of them, with few matches on the Zazycki and Zieliński sides.

Of course, any time one observes a lack of DNA matches to one particular line, there’s always the possibility of a misattributed parentage event, also known as a non-paternity event, or NPE. I’d be more likely to suspect this if Mom had no matches to a particular line, rather than a few distant ones. I’d be even more likely to suspect an NPE if I could find documentary evidence to suggest that a family was large and had plenty of descendants, and she still had no DNA matches. However, the fact that Mom has DNA matches to documented cousins on her Zielinski and Zazycki lines, and that the amount of DNA shared between her and those matches is within the expected range for the documented relationships, suggests that NPEs are not the issue here. (Or at least, it suggests that there are no NPEs that occurred in the generations between Mom and the ancestral couple shared between her and each DNA match.)

Rather than viewing the glass as half empty, it might be better to focus on all those DNA matches to the Grzesiak and Klaus families. Columns 5 through 10 indicate which matches are descendants of particular ancestral couples. In the case of the relatively close DNA matches shown in Figure 1, all but two of the Grzesiak matches are descendants of mom’s great-grandparents, Józef Grzesiak and Marianna Krawczyńska, as indicated by the light blue bars in column 5. The other two matches near the bottom, which are noted with a dark blue bar but not a light blue one, are not in my tree yet, so additional work is needed to make the documentary connection. However, we know they must be related somehow to the Grzesiak family because of all the matches they share in common with documented Grzesiak descendants. The Klaus matches are even more abundant, and can be broken down into descendants of various couples who were ancestors of either Andrzej Klaus, mom’s great-grandfather, or Marianna Łącka, mom’s great-grandmother.

Autoclusters: The Leeds Method on Steroids

Of course, thanks to the wonders of modern technology and gifted software engineers, we can go one better. Figure 2 shows a screenshot of the top portion of Mom’s autoclusters report at MyHeritage.

Figure 2: Autoclusters report from MyHeritage for Mom’s DNA matches. Click figure for larger image. Typically names of testers appear above the columns and to the left of the rows, but they’ve been removed here for privacy purposes.

This utilizes the same principle as the Leeds Method spreadsheet, except it does the heavy lifting for you, automatically clustering your matches into groups which likely share a common ancestor. Each square on the grid represents a comparison of one of Mom’s DNA matches to another, and colored squares represent two people who match each other, in addition to matching my mom. You’ll note that there are some uncolored squares within each cluster; these occur because it’s possible that two members of a cluster will not match each other (even though they both match Mom) due to the random nature of DNA inheritance. So, I can gain insight into Mom’s relationship to all the members in the orange cluster shown in Figure 2, simply by determining her connection to one member of this cluster.

While it’s sometimes possible (e.g. with DNAGedcom) to vary the parameters for inclusion to create tighter or looser groups, that’s not possible with the autocluster tool at MyHeritage. MyHeritage utilizes an algorithm that automatically adjusts that parameters to yield the best clusters for each kit. Note also that not all of a tester’s matches will appear on the grid. MyHeritage provides a ReadMe file with each autocluster analysis which specifies the parameters that were used, the number of kits included in the analysis, and the names of DNA matches who were not included in the analysis as well. In my mom’s case, 109 DNA matches were used to create 26 clusters; 41 matches were excluded because they did not have any shared matches, and another 127 matches were excluded because, although they met the criteria for inclusion in the analysis, they would have ended up in singleton clusters (matching each other and Mom and no one else).

As MyHeritage states in their explanatory ReadMe file, “Everyone in a cluster will be on the same ancestral line, although the most recent common ancestor between any of the matches, and between you and any match, may vary. The generational level of the clusters may vary as well. One may be your paternal grandmother’s branch, and another may be your paternal great-grandfather’s branch.” This can be illustrated using the red cluster shown at the top left in Figure 2. This cluster represents 10 testers who are related to Mom through her grandmother, Weronika Grzesiak. I know how we’re related to eight of them: five of the matches share Weronika’s parents, Józef Grzesiak and Marianna Krawcyńska as the most recent common ancestral couple, and three share Józef Grzesiak’s maternal grandparents, Maciej Dąbrowski and Barbara Słońska, as the most recent common ancestral couple. Descendants of this couple were highlighted in light blue in Figure 1. So, the remaining two mystery matches in that red cluster shown in Figure 2 might be related to to Mom through a bit of DNA inherited from any of the ancestors of Weronika Grzesiak; we can’t really claim to know anything more definitive than that from these data.

The beauty of the autocluster option is that it eliminates the necessity of going through a match list by hand and tagging each match with a colored dot based on shared matches. Although the clusters themselves are extremely informative, it’s also worth noting the DNA matches who were omitted from the cluster analysis. In Mom’s case, one of the matches who was omitted due to lack of any shared matches was a 5th cousin who matches her through her Wilczek line. Since Mom descends from the Wilczeks through her paternal grandfather, it’s disappointing, but unsurprising, that there are no shared matches between Mom and her Wilczek 5th cousin, given the general lack of DNA matches who are related to Mom through either of her grandfathers.

Extrapolating to Other Surname Lines

For want of a better term, I’ll call the relative lack of DNA matches to Mom through either of her paternal grandfathers the “Small Family/International Family Effect.” Unfortunately, it seems to be at work on my Dad’s side of the family as well. I had high hopes that DNA testing might provide some clues regarding the birthplace in Ireland of my great-great-great-grandfather, Robert Walsh. Despite the fact that I’ve identified DNA matches with whom Robert Walsh and his wife, Elizabeth Hodgkinson, are the most recent common ancestors, DNA has not provided any strong leads to Walsh relatives in Ireland as of yet. I’ve even tested my father’s 100-year-old paternal aunt, whose great-grandfather was Robert Walsh. She would be expected to have more numerous and genetically closer DNA matches to this line than I would, since she inherited a greater percentage of Robert Walsh’s DNA. One might have expected that some of her matches would include Walshes from a particular location in Ireland, or even that one region of Ireland might stand out as an area from which a preponderance of DNA matches originated. However, no great leads have turned up yet. Similarly, DNA has not been especially illuminating as of yet with another brick wall ancestor, Maria Magdalena (née Causin/Casin/Couzens/Curzon) Roberts, who also seems to have come from a very small family which left few descendants. Does that mean that my DNA test results can’t help me? No, it just means that there’s nothing obvious to leverage, no low-hanging fruit to harvest.

There is hope, of course. By identifying “autoclusters of interest” that seem to share common ancestors on my brick-wall lines, I can examine their family trees of DNA matches within those clusters, or attempt to build family trees for them if none are available, and search for common surnames and ancestral locations. It should be noted that some sites (e.g. DNAGedcom) even have automated tools for identifying common ancestors based on GEDCOM files (family tree files) that are associated with DNA test kits. Another possible approach is to use research into an ancestor’s social network of friends, associates and neighbors (i.e. his “FAN club”) to identify putative parents for a brick-wall ancestor, trace their descendants forward to the present day, and then do autosomal target testing on individuals who would be predicted to share DNA, based on this hypothesis. Where there’s a will, there’s usually a way.

It can be incredibly rewarding to connect DNA matches to your family tree. Thanks to DNA matches, I’ve been able to discover and connect with distant cousins that I never knew I had, some of whom have even been willing to share old family photos. I’ve been able to track down a number of “lost” siblings of my ancestors who disappeared from the records. And DNA is an especially powerful tool when leveraged for tracking migrations of relatives with popular surnames. However, small families with few descendants can produce “lopsided” DNA match lists, which can be readily visualized using Leeds and Collins-Leeds clustering techniques. While these analytical methods won’t fix “structural defects” in your family tree, they can help you make the most of the matches you do have.

© Julie Roberts Szczepankiewicz 2021

DNA to the Rescue! Evidence for Helena Panek’s Parentage

In my last post, I wrote about my research into my newly-discovered Panek ancestry. To briefly recap, the marriage record for my great-great-great-grandparents, Michał Zieliński and Antonina Ciećwierz, stated that Michał was the son of Piotr Zieliński and Marianna Panek. Piotr and Marianna’s marriage record is indexed in Geneteka, and states that Marianna was the daughter of Helena Panek, with no father’s name given. Although this suggests that Helena was an unwed mother, I believe she was actually Helena (née Święcicka) Panek, wife of Tomasz Panek, of Kuznocin in Sochaczew County. The fact that Helena was married to Tomasz Panek at the time of Marianna’s birth does not necessarily mean that Tomasz was Marianna’s father, however, so the question remains as to whether he was named on Marianna’s marriage record and merely omitted from the index, or whether the marriage record itself states that Marianna’s father is unknown. Of course, the actual marriage record is needed here and may shed some light on the situation, and I have requested a copy from the diocesan archive in Łowicz. However, since I requested a large number of records, and since the archive is closed from now until the end of July, it might take some time before I have Marianna’s marriage record in my eager little hands. Since patience is not always my virtue, I turned to DNA to see if there was evidence to prove or disprove my hypothesis that Marianna Panek was the daughter of Tomasz Panek and Helena Święcicka.

Panning for Paneks

Considering the distant time frame of the research problem, it’s better to analyze my mother’s DNA match list rather than my own, since she is one generation closer to these elusive Panek/Święcicki ancestors than I am. I searched her matches at Ancestry for the surname Panek, and came up with 3 distant cousins with this surname in their family trees. Of these matches, two had family trees which were locked, and one had a public tree. I could request access to the locked trees, but I have no reason to suspect anything earth-shattering there, because the matches are only 10 centimorgans (cM, a unit of genetic distance) across 2 segments, and 7 cM across 1 segment, respectively. Such small segments suggest a very distant match at best, or perhaps even a matching segment that is identical by chance (a false positive). The public family tree of the third Panek match revealed that his Panek family was from Oblekon, Świętokrzyszkie province, which isn’t especially close to Sochaczew, where my Panek family lived. Panek is not an uncommon surname, and moreover, that match, too, was only about 10 cM, so it won’t be an easy task to identify our common ancestors.

The fact that Mom doesn’t yet have any strong matches to Panek cousins does not in itself offer evidence regarding the question of whether Tomasz Panek was Marianna’s father. It’s entirely possible that Tomasz Panek could have been Marianna’s father, but that Mom simply did not inherit the right bit of DNA to match another of Tomasz Panek’s descendants. It’s also entirely possible that a match will show up some day as more people test. At the moment, the vast majority of Mom’s 117 DNA matches at the level of 4th cousins or closer, appear to be people living in North America who have traced their ancestry back to Poland, rather than Poles living in Poland today. DNA testing is still unaffordable for many Poles, and Ancestry DNA is not well known in Poland, so there are very few Poles in their database. As DNA testing becomes more affordable, hopefully the situation will improve and more Poles will become interested in testing with Ancestry, increasing the likelihood that I’ll find cousins from Poland in my match list. However, at this point, the search for cousins from the Panek family didn’t pan out, so it was time to try a different angle.

Searching for Święcickis

I searched Mom’s matches for the surname Święcicki with much more promising results. A fourth-cousin match immediately popped up to “D.K.,” as well as one 5th-8th cousin match to “J.G.” Both of them have public trees, and based on these trees, D.K. and J.G. are related to each other as well as to Mom. Note that diacritics matter when searching DNA matches in Ancestry, as a search for “Święcicki” will produce different results than a search for “Swiecicki.” If you try to get around this problem by checking the box to include similar surnames, all hell breaks loose. In the case of this search, Mom’s list suddenly jumped from two matches to 68 matches, many of whom had surnames that weren’t remotely close to Święcicki/Swiecicki. Rather than wading through all these matches, I chose to focus on just the first two Święcicki matches see if I could determine how we might be related.

The Gontarek Family of Minnesota and Młodzieszyn

Both J.G. and D.K. trace their ancestry back to the Gontarek families of Minnesota. Their family trees document several siblings — Michał, Wiktoria, Ludwik, Rozalia, Bronisława, and Lena — who emigrated from Russian Poland to locations in Steele, Le Sueur, and Waseca Counties, west and south of the Minneapolis/St. Paul area. The fact that they settled in the Minneapolis/St. Paul area was immediately interesting to me, since previous research led to me discover that this area was the destination for other ancestral cousins from Sochaczew County. Although the family trees are well-documented through census records, it’s not immediately clear what evidence they have for the names of the parents of these siblings, since the trees are a little light on vital records. Nonetheless, both family trees report that these immigrants were all children of Stanisław Gontarek and Marianna Święcicka. Furthermore, J.G.’s tree states that Marianna Święcicka was the daughter of Piotr Świecicki and Anna, maiden name unknown, and that she died in Kuznocin on 9 December 1890, and in her gallery, I found a note indicating that she hired a professional genealogist in Poland to find this information.

By this point I was sitting on the edge of my chair. Kuznocin was exactly where my Święcicki ancestors were from, so this could not possibly be a mere coincidence. A quick search in Geneteka revealed the births of most of these siblings in Sochaczew and nearby parishes, including Młodzieszyn, where the most recent generations of my Polish family lived (Figure 1).

Figure 1: Geneteka search results for births of children born to couples with surnames “Gontarek” and “Sw,*” searching as a pair in Sochaczew and indexed parishes within a 15-kilometer radius.

Gontarek births

My matches’ family trees suggest that “Lena” was born circa 1860, so she may be the same as the Julianna who was born in 1858. Józef and Walenty are new — perhaps they remained in Poland and did not emigrate, or perhaps they died young. There are unfortunately no death records for any of these individuals, but at least 4 of them emigrated to the U.S. and died there, so their deaths would not be indexed in Geneteka. There is also no birth record for the Ludwik/Louis found in the Gontarek family trees on Ancestry. He was born circa 1872, but if he were born in Młodzieszyn like Bronisława, that could explain his absence from this list, since indexed birth records for Młodzieszyn don’t begin until 1885. In fact, if the family moved to Młodzieszyn after the birth of Walenty in 1870, that could also explain the 15-year gap in births that appears between Walenty and Bronisława. A move to Młodzieszyn would similarly explain the absence of marriage or death records for Józef and Walenty, since all records for Młodzieszyn that are available from the state archive in Grodzisk Mazowieckie are very limited. (Between the archive and the local civil records office, marriage records exist from 1889-1898 and from 1911-1928, and death records exist from 1889-1925. Additional, more recent records after 1928 are almost certainly available as well, but access to records after 1937 is restricted to immediate family.)

Bronisława’s birth record from 1885 is the only one linked to a scan. Birth records for the Gontarek children who were baptized in Sochaczew are only available at the diocesan archive in Łowicz, and Rozalia’s birth record from the parish of Brochów is in the possession of the parish archive. Working with what we have, then, let’s take a quick look at Bronisława’s birth record (Figure 2).1

Figure 2: Birth record from Młodzieszyn for Bronisława Gontarek, 3 August 1885.1

Bronislawa Gontarek birth 1885 marked

In translation from Russian, the record states that Bronisława was born in Młodzieszyn on 3 August 1885 at noon. Her father was described as Stanisław Gontarek, a laborer residing in the village of Młodzieszyn, age 59. The text pertaining to her mother, underlined in red, states that the child Bronisława was born “….of his [Stanisław’s] lawful wife, Marianna née Swięcicka, age forty-eight.” Marianna’s age suggests that she was born circa 1837, and if that was the case, then she would have been about 21 at the time of Julianna Gontarek’s birth. This is quite reasonable, and consistent with the hypothesis that all the children found in our Geneteka search belong to the same couple.

So far, so good. We’ve found additional evidence to support the information found in the family trees of Mom’s DNA matches, indicating that the Gontarek siblings who settled in Minnesota were children of Stanisław Gontarek and Marianna Święcicka or Swięcicka of the parishes of Sochaczew, Brochów, and Młodzieszyn, all located in Sochaczew County. The next step was to find Marianna Gontarek’s death record, which was discovered by the professional genealogist in Poland and was the basis for the information in J.G.’s family tree that Marianna Święcicka was the daughter of Piotr Święcicki and Anna, maiden name unknown, and that she died in Kuznocin on 9 December 1890. This document was easily located in Geneteka (Figure 3).2

Figure 3: Death record from Młodzieszyn for Marianna Gontarek, 9 December 1890.2

Marianna Gontarek death 1890

Here’s the full translation of this document from Russian, as I read it:

“A. 79, Biała Góra. This happened in the village of Młodzieszyn on the 29th day of November/11th day of December in the year 1890 at 11:00 in the morning. They appeared — Maciej Szewczyk, laborer, age 46, and Stanisław Giza, laborer, age 26, residing in the village of Biała Góra — and stated that, on the 27th day of November/9th day of December of the current year, at 4:00 in the morning, died in the village of Biała Góra, Marianna Gontarek, wife, laborer, age 56, born in the village of Kuznocin, residing in the village of Biała Góra, daughter of the late Piotr and Anna, the spouses Swięcicki. She leaves after herself her widower husband, Stanisław Gontarek, residing in the village of Biała Góra. After eyewitness confirmation of the death of Marianna Gontarek, this document was read to the illiterate witnesses and was signed by us only. [Signed] Fr. Antoni Morski.”

Since Marianna was reported to be age 56 when she died in 1890, she was probably born circa 1834. Lo, and behold, there are two matching birth records in Geneteka for Marianna Święcicka or Swięcicka in 1835, recorded in Sochaczew which is the correct parish for the village of Kuznocin (Figure 4).

Figure 4: Search result for birth of Marianna Swiecicka, born between 1830 and 1840 in Sochaczew parish.Marianna Swiecicka birth

The two records shown here are the civil record and the church record. It’s possible to tell which is which because the “i” infodot in the “Remarks” column indicates that the second record was taken from the Latin church book, so the first record must be the Polish-language civil transcript. Both versions are only available from the diocesan archive in Łowicz, so it looks like I’ll be placing another order with them. Marianna’s mother’s maiden name is recorded as Janiak, which is new information for me, and presumably for my DNA matches as well.

Another search in Geneteka quickly produced Piotr and Anna’s marriage records — and revealed how I am related to D.K. and J.G. (Figure 5).

Figure 5: Geneteka search result for marriage of Piotr Swięcicki and Anna Janiak.

Piotr and Anna Swiecicki marriage

Piotr was the son of Stanisław and Urszula Święcicki, my putative 6x-great-grandparents!


I say “putative,” because at this point I still don’t have a single shred of direct documentary evidence that I have any ancestors with the Swięcicki/Święcicki surname. I only have a theory based on indirect evidence that my documented ancestor, Helena Panek, was born Helena Swięcicka, daughter of Stanisław and Urszula. Up until this point, one could argue that there might still be an unmarried Helena Panek who was actually my ancestor, but who was not found in the indexes in Geneteka because those indexes are incomplete and don’t cover every year in every parish in the vicinity of Sochaczew. However, the discovery of this DNA evidence certainly adds substantial weight to my theory. Based on the paper trail, both J.G. and D.K. are 5th cousins once removed to my mother, and the amount of DNA shared by my mother with each of them supports this relationship. Due to the random nature of DNA inheritance through recombination, D.K. and my mother share 40 cM of DNA over 2 segments, while J.G. and my mother share only a single segment of 8.6 cM. However, both of these values fall within the normal range of centimorgans shared by people who are 5th cousins once removed. According to Blaine Bettinger’s handy Shared cM Project chart, people who are 5th cousins once removed might share anywhere from 0 to 79 cM of DNA, with an average of 21 cM shared DNA.

Of course, the DNA evidence in itself is not “proof” of my descent from Stanisław and Urszula Swięcicki. It’s true that DNA doesn’t lie, but in cases such as this, where DNA evidence is used to confirm a relationship that’s further back than parent-child, DNA evidence is still open to interpretation. The possibility exists that Mom (and I) might be related to D.K. and J.G. through some other set of common ancestors. However, one can invoke the law of parsimony here and conclude that Stanisław and Urszula are, indeed, our common ancestors because that explanation is the simplest, given the substantial body of indirect documentary evidence that’s accumulated. To put it another way, when you hear hoofbeats, expect horses, not zebras.

I just love it when the pieces fall into place like this. I just heard back yesterday from both J.G. and D.K., and I’m delighted to have an opportunity to share all this new information with them. And of course, I still can’t say whether Tomasz Panek was Marianna’s father or not, so that remains a mystery for now. Hmmm….. maybe I’ll go and reexamine those DNA matches with the surname Panek in their family trees. This may be my lucky day!


1 “Akta stanu cywilnego parafii rzymskokatolickiej w Młodzieszynie” (Młodzieszyn, Sochaczew, Mazowieckie, Poland), Księga urodzeń 1885-1895, 1885, no. 105, birth record for Bronisława Gontarek, 3 August 1885, accessed as browsable images, Polskie Towarzystwo Genealogiczne, ( : 20 July 2018).

2“Akta stanu cywilnego parafii rzymskokatolickiej w Młodzieszynie” (Młodzieszyn, Sochaczew, Mazowieckie, Poland), Księga zgonów 1889-1901, 1890, no. 79, death record for Marianna Gontarek, 9 December 1890, accessed as browsable images, Polskie Towarzystwo Genealogiczne, ( : 20 July 2018).

© Julie Roberts Szczepankiewicz 2018