X Chromosome Redux: Sogndal v. Hafslo

Following up on my X-Chromosome post from a couple months ago,^[1]See it here. I found two new DNA matches on my X Chromosome that allow me to assign even deeper Norwegian ancestry to some segments.

As background, the image above shows 2GGs Petter Pettersen Aaberge (1835-1909) and Dorthe Eriksdatter Alme (1838-1938), probably taken at the time of their wedding at Stedje Church in Sogndalsfjiøra, Norway in 1866.  Their separate ancestries are the key to this article.

Actually, it is their geographic origins that are the key.  On the one hand, the ancestry of Petter Pettersen Aaberge is wholly Sogndal in origin.  Note the location of Sogndal and Luster counties in the southern third of Sogn og Fjordane County in the map below.

Petter’s ancestors going back at least 3 generations all resided in Sogndal parish, Sogn og Fjordane County, Norway.^[2]I use the old county names even though Sogn og Fjordane was merged into the new Vestland County in 2020.  Associated farm names included Aaberge, Vikheim, Kvam, Tuftene, Geirane, and Gorvin, within close proximity to the village of Sogndalsfjiøra.

Dorthe Eriksdatter Alme, on the other hand, was born in Hafslo Parish in Luster County.^[3]See my blog post about this discovery here.  Dorthe only lived in Hafslo a couple months.  Her family moved to Vassli farm in Sogndal parish when she was a baby, and then to one parcel of the … Continue reading  All Dorthe’s ancestry going back at least 3 generations is from the north side of Lake Hafslo (Hafslovatnet).  See the map below which shows the farm area where her ancestors lived, circled in blue.  Relevant Hafslo farm names in our family tree include Venjum, Alme, Lad, Tang, Sølvi, Beum, and Høgi.  The distance from the Hafslo and Sogndal farms is about 12 miles. Note the Aabyrge farm located on a high ridge just above Sogndalsfjøra.  (Click on the image to zoom in, if necessary.)

Here again are the phased X chromosomes for the Jonnes siblings.  The chromosomes relevant to this discussion are our Maternal X Chromosomes, indicated by the purple and green colors.  We’ve already established that all Bonn segments must originate with great-grandmother Bertha Aaberge (1865-1936).  We could in fact edit the chart to replace all Bonn segments with the Aaberge name.  In my case (Steven), for example, the larger Bonn segment came from my mother’s Paternal X Chromosome, thus Aaberge, while the smaller Vermilyea segment to the right came from my mother’s Maternal X Chromosome.

As the inheritance chart shows, Bertha Aaberge’s X-DNA, in turn, derives from either her paternal grandmother Berte M. Vikheim (1812-1883) from Sogndal parish – or her mother, the aforementioned Dorthe Eriksdatter Alme from Hafslo parish.  (Dorthe’s X inheritance comes from either Ingeborg Jørgensdatter Tangstræ or Margrethe Larsdatter Lad, but we’re unable to assign any segments to them yet.)

 

The first new DNA match, whom I’ll nickname Setter, allows us to distinguish between these Sogndal and Hafslo ancestries.   Setter and I share a segment from 0 to 9.6 megabase points (Mb) – about 14 centimorgans – on my X Chromosome.  Setter is a known 3C1R to my siblings and I.  Our common ancestors are 3GGs Erik Olsen Venjum (1802-1892?) and Margrethe Larsdatter Lad (1799-1882), Dorthe’s parents.^[4]The Venjum and Lad farms are right next to the Alme farm where Dorthe was born.

Therefore, the segment that Setter and I share at the beginning of my mother’s paternal X Chromosome is Hafslo in origin.  Note that Boyboy and Bizzy also inherited a Bonn segment in that part of their maternal X Chromosome and must share the Hafslo origin.  Only JazzMa shows a Vermilyea, not a Bonn, segment in that location.  My mother matches Setter in the same X Chromosome location, thereby confirming the association.

Setter and I also share a tiny segment on the same chromosome from 27.2 – 29.8 Mb.  I had discounted it because it was so small.  One of the principles of genetic genealogy is to view smaller segments, especially those below 7 centimorgans, with skepticism.  The smaller the segment, the higher the possibility of a false positive.

But then I noticed that other matches – including several for whom I cannot identify the common ancestor beyond a shared Norwegian origin – begin or end at the same 29.8 Mb location.  In total, I have three matches whose shared ancestry with me ends at 29.8 Mb, and three other matches who begin at nearly the same point.  See my X-Chromosome diagram below.  The matches were combined automatically into one image by the software, DNAPainter.com.  There are actually six separate individuals who either begin or end right at 29.8 Mb.

This configuration suggests that the Haflso portion of my mother’s paternal X Chromosome begins at zero and ends at 29.8 Mb, and that a different Aaberge ancestral segment begins at 29.8 Mb.  Logically, that second segment must be derived from Bertha’s paternal grandmother, Berte M. Vikheim, a Sogndal ancestor.

The second new DNA match, nicknamed Vindi, supports the Vikheim designation.  Vindi is a confirmed descendant of my 4GG Vikheim-Kvam ancestors.  We match on the X Chromosome from 73.4 – 97.8 Mb (17.7 cM).

Visual phasing previously demonstrated that my X-Chromosome was divided into two grandparent segments (Bonn and Vermilyea).  Chromosome painting now has taken that one step further and revealed 4 ancestral lines within the two segments.

Visual Phasing results:

• Bonn segment (0 – 132.9 Mb)
• Vermilyea segment (132.9 – 154.9 Mb)

Chromosome painting results:

1.  Haflso segment (0 – 29.8 Mb)
2.  Sogndal segment, Vikheim (29.8 – 102.5 Mb)
3.  Aaberge segment (102.5 – 132.9 Mb)
4.  Vermilyea segment (132.9 – 154.9 Mb)

Note the third segment.  Much of the space between 102.5 and 132.9 Mb is vacant, reflecting the fact that I have painted only one DNA match there.  The entire section has to be Aaberge because visual phasing showed it came from my Bonn grandfather.

The single match between 102.5 – 132.9 Mb is nicknamed Mindy.  Mindy and I share 16 cM from 117.3 – 125.6 Mb.  You may see it colored in dark purple in the dnapainter.com image above, labeled Aaberge.  I can’t determine if Mindy is descended from Sogndal or Hafslo ancestors.  It is possible that the Vikheim segment (Sogndal) continues from 102.5 Mb all the way to the end of my Norwegian heritage at 132.9 Mb.  Or possibly my mother had another crossover in her paternal X Chromosome somewhere between 102.5 and 132.9 Mb, which would belong to the Hafslo side.  We just don’t know yet.  Deeper analysis of my siblings, but especially my mother’s, matches may answer this.