23andMe – Barking up the family tree (2024).

In December 2023 Barbara and I decided to give ourselves as a Christmas present DNA analysis kits from 23andMe, a well-known ancestry website. The analysis would provide us with specific information about our ancestry, physical traits, and if desired, a summary assessment of genetic proclivity to various medical conditions and diseases.

Figure 1 – 23andMe sampling container.

The kits were ordered from Amazon for $79, each, and delivered via Amazon Prime to our apartment on December 13. We placed them under the Christmas tree to open them up after Christmas. Having opened the kit, we followed the instructions for saliva sample collection and forwarded them to the 23andMe mailbox.

As we opened the kits we found a plastic funnel-shaped saliva collection tube with user instructions. The first step was to register your kit with a 14-digit personal number. We were instructed not to eat or drink anything for half an hour before collecting the saliva sample.

The sampling tube is shown in Figure 2. After opening the funnel, you are expected to spit repeatedly inside it until a small quantity, about 0.5 ml, has been collected. The funnel is subsequently removed and the tube is sealed with a screw cap, sealed in a plastic bag, and to be shipped to the 23andMe mailing address. Thereafter, you wait for the sample analysis to be completed and learn the results in a series of emails sent by the 23andMe website.

Figure 2 – 23andMe sampling tube.

23andMe religiously keeps you informed about the progression of the sample and data analysis. On January 22, I received an email from 23andMe, with the notification that the results of the DNA analysis were in and I would be able to watch them by entering my personalized portal to the website.

Ancestry.

The first report, perhaps the most keenly awaited, summarizes your ancestry composition. According to the summary (Figure 3), I am 100% Northwestern European, classified as 92.4% French & German with a further emphasis on South Holland (Netherlands: highly likely match) and Flanders (Belgium: likely match). Unexpectedly I also had 7.1% Scandinavian ancestral DNA (unspecified as to what country). Then there was a trace, 0.5%, of broadly Northwestern European. Within the total DNA, there was also a small percentage, < 2% of DNA, that can be traced back to Neanderthal lineage.

None of this surprised me. Both my parents were born in the Dutch province of South Holland, my father in the city of Leiden, and my mother, like me, in the port city of Rotterdam. My father’s father was born in the town of Voorschoten, near the Hague, and his mother, like him, in Leiden. On my mother’s side, her father was born in Grietherort, a German town on the Rhine River, near the border with the Netherlands. He became a citizen of the Netherlands in 1918. My mother’s mother was born in Dordrecht, a city near Rotterdam.

Figure 3 – Ancestry Composition.

The DNA inheritance was further clarified. Both maternal and paternal lineage were addressed. The maternal side is analyzed from mitochondrial DNA. Mitochondria are the cellular energy processing organs in the cell and they have their own DNA which is always inherited from the mother. The Y-chromosome is only present in males and it provides information about the paternal DNA line.

There are key concepts in genetics that are relevant to DNA. The first is that of a nucleotide, the key building block of the DNA and RNA molecules. Chemically, a nucleotide consists of a pentose sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base (Figure 4). DNA has four variations in the nitrogen-containing base: adenine (A), cytosine (C), guanine (G), and thymine (T).

Figure 4 – The basic structure of DNA.

DNA is a double helix of complementary nucleotides, chemically bonded to each other as shown in Figure 5. T always goes with A, and C with G. T-A and C-G are termed base pairs. Human DNA consists of about 3 billion base pairs. Small changes in the DNA composition determine the physical differences between humans.

RNA is a single strand of nucleotides. In RNA, the base uracil (U) takes the place of thymine. DNA and RNA molecules are polymeric molecules made up of long chains of nucleotides.

Figure 5 – Schematic of the DNA double helix.

An allele is a variant of the sequence of nucleotides at a particular location on a DNA molecule.

A haplotype is a combination of alleles at different chromosomal regions, in closely proximity, that are inherited.

A haplogroup is determined by a group of similar haplotypes that share a common ancestor with a single-nucleotide polymorphism mutation. Individuals in the same haplogroup show a large overlap in their genetic makeup and are related.

Haplogroup H is a major genetic characterization whose frequency in Europe is in the 40%-50% range. The genetic mutation defining haplogroup H took place at least 25,000 years ago. A later genetic mutation that occurred about 7,000 years ago resulted in haplogroup H6a1a, and individuals with this mutation are found within the ‘Corded Ware’ and ‘Bell Beaker’ cultures which comprise a broad archaeological horizon of Eastern and Central Europe between c. 3000 BC – 2350 BC, from the late Neolithic, through the Copper Age, and ending in the early Bronze Age. The Netherlands is at the western edge of this archeological region. H6a1a was identified by 23andMe from analysis of my mitochondrial DNA. Its presence indicates that my forebears from my mother’s side lived in Western Europe for many millenniums.

The Y chromosome provides information about the paternal DNA line. My paternal haplogroup is R-L2, thought to have originated around the Alps or southern Rhine, and was formed when it branched off from the ancestor R-U152 and the rest of mankind around 2550 BCE. The oldest person with this haplogroup was found in Czechia and the individual belonged to the ‘Bell Beaker’ culture. Again, tracing my paternal lineage back to tribes that lived in the Alps or along the Rhine 4,500 years ago, places my father’s origin in Western-Central Europe and is hardly earth-shattering.

The maternal ancestral mitochondrial DNA and paternal Y-chromosome DNA analysis results are wholly consistent with my lineage being from Western Europe.

As for the 7.1% of Scandinavian ancestral DNA, it might have resulted from the influx of northern people from Scandinavia into more southern regions which occurred regularly over the past millennia as well as Viking raids into continental Western European communities during the early Middle Ages.

Traits and Physical Features.

In addition to the ancestral DNA analysis, 23andMe also sent me an exhaustive list of heredity-related physical features that might be of interest.

A summary of traits mentioned in the report is given below. For some of them, I asked myself: why mention it? Why bunions, cleft chin, earwax type, ice cream flavor preference, unibrow? The genetic significance seems remote.

Ability to Match Musical Pitch — More likely to be able to match a musical pitch.

Asparagus Odor Detection — Likely can smell.

Back Hair — Likely little upper back hair.

Bald Spot — Likely bald spot.

Bitter Taste — Likely can taste.

Bunions — More likely than average to have had a bunion.

Cheek Dimples — Likely no dimples.

Cilantro Taste Aversion — Slightly higher odds of disliking cilantro.

Cleft Chin — Likely no cleft chin.

Dandruff — Less likely to get dandruff.

Earlobe Type — Likely detached earlobes.

Early Hair Loss — Likely hair loss.

Earwax Type — Likely wet earwax.

Eye Color — Likely blue or green eyes.

Fear of Heights — Less likely than average to be afraid of heights.

Fear of Public Speaking — Less likely to have a fear of public speaking.

Finger Length Ratio — Likely ring finger longer than index finger.

Flat Feet — Less likely than average to have flat feet — I do have flat feet.

Freckles — Likely little freckling.

Hair Photobleaching — About a 50/50 chance of experiencing hair photobleaching.

Hair Texture — Likely straight or wavy hair.

Hair Thickness — Less likely to have thick hair.

Ice Cream Flavor Preference — About a 50/50 chance of preferring vanilla or chocolate ice cream.

Light or Dark Hair — Likely dark hair.

Misophonia — Less likely to hate chewing sounds.

Mosquito Bite Frequency — Likely bitten less often than others.

Motion Sickness — Less likely to experience motion sickness.

Newborn Hair — Likely little baby hair.

Photic Sneeze Reflex — Likely no photic sneeze reflex.

Red Hair — Likely no red hair.

Skin Pigmentation — Likely lighter skin.

Stretch Marks — Less likely to have stretch marks.

Sweet vs. Salty — Likely prefers salty.

Toe Length Ratio — Likely big toe longer.

Unibrow — Likely no unibrow.

Wake-Up Time — Likely to wake up around 6:44 am.

Widow's Peak — Likely no widow's peak.

The list was also supplied as a summary with probabilities, i.e. the chance of having or not having a specific feature. But this list didn’t change the conclusions. In general, I agree with the features noted, but sometimes, there is a discrepancy. For example, I know that I’ve had severe dandruff for at least a part of my life, while there was a three-to-one chance I would not have. Hair color is 50/50 between dark brown or black versus shades of blond. Over my lifetime, my hair color has varied from light blond as a child to medium brown as an adult.

Health Predisposition, Carrier Status, and Wellness Reports.

After I paid an additional $125 to 23andMe, I received a series of health reports. One of the reports summarizes the chances of developing certain health conditions. Fourteen different conditions were addressed, and the DNA analysis did not detect genetic variants for most of them. The only genetic predispositions were for Celiac Disease (slightly increased risk) and Type 2 Diabetes (typical likelihood). I was glad not to have variants indicative of late-onset Alzheimer’s Disease, Parkinson’s Disease, and Prostate Cancer, conditions that are prevalent among seniors.

Additionally, there were 46 conditions addressed in Carrier Status Reports. These refer to genetic variants which may not affect my own health, but could affect the health of my children. Variants for these 46 conditions were not detected.

The health section of 23andMe also contains eight reports about how my DNA can affect my body’s response to diet, exercise, and sleep. The topics discussed are:.

1) Alcohol flush reaction — I’m unlikely to flush upon consumption of alcohol.

2) Caffeine consumption — I’m likely to consume less.

3) Deep sleep — I’m less likely to be a deep sleeper.

4) Genetic weight — I’m predisposed to weigh about average.

5) Muscle composition — My muscle composition is similar to that of elite athletes.

6) Sleep movement — Likely average or less movement in sleep.

7) Lactose intolerance — I’m likely lactose-intolerant.

8) Saturated Fat and Weight — My weight is similar on diets high or low in saturated fat with the same total calories.

Related People.

23andMe also keeps track of people you share DNA fragments with. I was given access to a list of names of 1,500 people with whom I share a small fraction of my DNA. Almost all of these are listed as distant cousins, to the third, fourth, fifth, or sixth degree. The commonality in DNA is less than 0.5% (3 or fewer segments) and none bears the van Roode family name. An exception is a first cousin, once removed, named Joosje van Roode with whom I have 9.87% DNA in common (23 segments). I presume she is a woman. She was born in 1986 and lives in New York. She is the child of a first cousin and the surname indicates my grandfather is also her great-grandfather. But I cannot remember ever having met her or heard about her.

Barbara received her DNA test results as well. Her ancestry was predominantly from the British Isles and to a lesser extent from Western Europe. But she may wish to tell her own story.

Since my interest in my ancestral DNA has been roused, I’ve ordered test kits from other sites as well. As the results become available, I’ll update this article.

MvR, May 31, 2024. ✍️