Estimating my Grandparents DNA Inheritance

I’ve been working episodically on my genetic genealogy for over four years.  My efforts involve Visual Phasing and Chromosome Painting.

Visual phasing is the process of identifying the crossover points on each chromosome and signifying their paternal or maternal ownership.  I discussed phasing my X chromosome in a previous post (click here).

Chromosome painting, on the other hand, involves using DNA matches to color your segments in a visual map, with each color representing one of your four grandparents — or even further back, including your great-grandparents, 2GGs, and so on.

One of my primary research goals is to figure out how much DNA I inherited from each of my four grandparents:

• Lloyd Jonnes (paternal-paternal)
• Barbara Lukemire (paternal-maternal)
• Bertram Bonn (maternal-paternal)
• Helen Vermilyea (maternal-maternal)

Chromosome map for Steven Nelson Jonnes, August 2024, 78% complete (DNAPainter.com)

The current status of this project is displayed above.  For each pair of numbered chromosomes, the paternal chromosome is displayed on top and the maternal below.  Green colors represent my paternal grandfather (Jonnes); Yellow my paternal grandmother (Lukemire).  On the lower half, Blue colors represent my maternal grandfather (Bonn); Red my maternal grandmother (Vermilyea).

• Jonnes  =   Green
• Lukemire =  Yellow
• Bonn    =    Blue
• Vermilyea = Red

Each person inherits 50% of their autosomal DNA from their father and 50% from their mother.  Therefore, my Jonnes and Lukemire DNA segments in combination must equal 50%; ditto with Bonn and Vermilyea.  However, because of the random nature of meiosis, you don’t necessarily receive 25% from each grandparent.  You may receive 26% from one and 24% from another, for example, or visa versa.  You could even receive more than 30% from one grandparent and less than 20% from the other.

Below are statistical analyses of the distribution bell curves for both the paternal and maternal grandparents.  What’s interesting is that paternal grandparent ratios have a broader distribution pattern than maternal ones, based on the fact that there are more segments in maternal chromosomes.

Distribution of DNA contribution ratios from paternal grandparents (DNAeXplained.com)

Distribution of DNA contribution ratios from maternal grandparents (DNAeXplained.com)

Analyzing my DNA inheritance is helped dramatically by the fact that my mother’s father, Bertram Bonn, was 100% Norwegian.  Anytime I encounter a DNA match on FamilyTreeDNA, 23andMe, AncestryDNA, or MyHeritageDNA who has a healthy percentage of Norwegian ethnicity, and especially if he or she has a Norwegian name or is living in Norway, I can be pretty sure it belongs to my Bonn heritage.

I still haven’t completely figured out my genome.  I am currently at 78% of  chromosomes painted on DNAPainter.com.^[1]See www.dnapainter.com, a wonderful DNA analysis tool.  Over the past 18 months or so, I gradually improved from the low 60s to the mid-60s in percentage coverage.  Just recently, however, I learned how to paint inferred segments from an online course taught by Michelle Leonard.^[2]See Michelle’s profile here: https://www.apgen.org/users/michelle-leonard.  Painting inferred segments catapulted my coverage by more than 10% in less than two weeks.

Inferred segments involve comparing your segments to a parent or sibling and deducing which segment belongs to which grandparent based on the comparison.  For example, let’s say my mother has a large segment on Chromosome 7 that definitively came from her father (Bonn).  If I did not inherit that segment, then we know that she passed her mother’s DNA (Vermilyea) in that location to me instead.

The following chromosomes are 100% done and painted:

4, 5, 7, 9, 11, 12, 13, 14, 17, 20, 21, 22 + maternal X chromosome

That’s 13 out of 23 chromosomes.

In addition, the following 7 chromosomes are probably done, but I’m not 100% sure that I have them right, or they are fully complete except for a very small segment.

1, 3, 8, 10, 15, 18, 19

That leaves 3 chromosomes that remain somewhat problematic.

2, 6, 16

I am nonetheless at the point where I can fairly accurately estimate how much of my genome is derived from each grandparent pair.  Here are the results:

Paternal —   Jonnes 32%,   Lukemire 18%

Maternal —  Bonn   23%,    Vermilyea 27%

Ranking them in order:

Jonnes        32%

Vermilyea   27%

Bonn           23%

Lukemire   18%

The maternal result does not surprise me.  In a conversation with my brother last year, I predicted I would end up slightly more Vermilyea than Bonn, like 26 or 27% to 23 or 24%.

The maternal result does not include the X Chromosome, even though the map above includes it.  The X Chromosome is separate from the autosomal chromosomes (Chromosomes 1 — 22).   My X chromosome is 86% Bonn.  Thus, if we add the X to the maternal total, the result changes from 23 — 27% to 24% —  26%.^[3]The autosomal comparison is what people typically cite because the size of the paternal and maternal autosomes is exactly the same.  When you add the X-chromosome to a male genome, there is an … Continue reading

A Surprise on the Paternal Side!

I’m blown away by the paternal result.  I expected to be more Jonnes than Lukemire, but the size of the difference is a shock.  I thought it would be more like 27% Jonnes, 23% Lukemire.

The map view below makes it easier to see the disparity on my paternal chromosomes.  Green clearly rules.  Thirteen of the 22 autosomes are predominantly Jonnes, only five Lukemire, and four are roughly 50-50.  The five heavily Lukemire chromosomes are #4, 12, 14, 19, and 21.

Paternal chromosome map, Steven Nelson Jonnes, August 2024 (DNAPainter.com)

What fooled me are the high number of Lukemire DNA matches.  My Lukemire matches are just as numerous as Jonnes matches, if not more so.  But in looking more closely, I have come to realize that Lukemire matches tend to bunch together.  There’s a large segment, for example, on Chromosome 10, about 65 centimorgans, where I literally have hundreds of Lukemire DNA matches.  It’s gotten to the point where I don’t even paint Lukemire matches on Chromosome 10 anymore.  In other words, my Lukemire matches are concentrated in fewer places.

The other factor is that until I began painting inferred segments I had large gaps on Chromosomes 1 and 2.  Both of the two largest chromosomes turned out to be predominantly Jonnes.

For comparison, here’s my maternal chromosome map:

Maternal chromosome map, Steven Nelson Jonnes, August 2024 (DNAPainter.com)

On the maternal side, I have 10 autosomes that are predominantly Vermilyea and 8 predominantly Bonn.  That’s not a big difference, but the four largest chromosomes are all Vermilyea dominant.  The most heavily Norwegian (Bonn) chromosomes are Chromosomes #5, 6, 15, 16, 17, and 22 — as well as the X chromosome.

In future posts, I will discuss contributions from earlier generations of ancestors in my map.  I will also analyze my siblings (JazzMa, Boyboy, and Bizzy) to see how much they’ve inherited from each grandparent.  My current hypothesis is that Boyboy inherited the most Lukemire and Bizzy is the most Norwegian.