23 April 2020

Family History, European History, Heredity And My Weight

As part of my weight loss program with Noom.com I also purchased a weight loss focused genetic test, took it and sent it off. I got a notice that my sample was received today by Orig3n, their commercial consumer grade DNA testing affiliate. I've already had DNA testing done by 23andMe and already known my family history with respect to most of the relevant issues, and family history is really still more powerful than DNA testing for discerning hereditary influences on complex traits.

I'll compare what I know from family history and a previous genetic test to the latest appraisal.

What do I know before receiving those results?


When I graduated from high school, I had a body mass index of 23.4 right in the middle of the "normal weight" range of 18.5 to 24.9. I wasn't particularly mindful of my diet, although I had lots of home cooked family meals, but I was moderately active. 

I was on the town's reaction center's summer swim team from late elementary school until through junior high school, and was on the high school swim team in the summer of my senior year. I also played soccer for many years in elementary school. In terms of athletic performance, I was dismally bad (as in pretty much the worst on every team I participated in for both swimming and soccer), but I was a good sport and tried my best. I was Cub Scout and then a Boy Scout (ultimately earning the Eagle Scout rank my senior year in high school), with the activities and outdoor hiking, camping and boating that this implied, and was involved in every theater production at high school and many of the community theater productions. I also biked around town for transportation and as a paper boy until I could drive late in my sophomore year of high school and in in senior year in high school (I was a foreign student in New Zealand during my junior year in high school and also fairly active then).

Once I was on my own, in college and then in law school, and then as a young lawyer, I was far more sedentary, although I walked to get places around campus, and ate with abandon when I had unlimited food available at the dining halls for all three years of undergrad and my first year at law school, and wasn't a weight conscious cook for myself. I put on a lot of weight in school, and then gradually added more over time.

The DNA test I took previously noted a couple of weight related genetic risk factors noting that my "genes predispose you to weigh about 4% more than average" (based upon a risk score derived from 760 different genetic markers) and that "people of European descent with genetics like yours have an estimated 32% chance of developing type 2 diabetes at some point between the ages of 49 (your current age) and 80." My expected weight for my gender, height, and age implies a BMI of 27.8 (in the overweight, but not obese range). 

Something on the order of 46.4% of American men my age in the United States from the general population are obese (defined as BMI 30.0 or more) without regard to genetics (estimating the cross tabs, adjusting for race as well would bring it down to about 46.1%), so the median is almost surely "overweight" (BMI 25.0 to 29.9) rather than being in the "normal range". About 11.5% of Americans my age in the United States from the general population are severely obese (defined as BMI 40.0 or more), as I was for several months in late 2017 and early 2018, although severe obesity is significantly less common (about a third less) in men than women (so the rate of severe obesity for men my age is probably closer to 10%), even thought men are more likely than women to be obese at all.

Also according to the DNA test that I took previously, my "weight is likely to be similar on diets high or low in saturated fat with the same number of total calories." I am correctly predicted to be lactose tolerant, and so far as I know, all of my genetic relatives are lactose tolerant.

Indeed, I was diagnosed with Type II diabetes in the spring of 2018 although I have since returned to non-diabetic status following a bit more than sixty pounds of weight loss on what amounts to basically a paleo diet, with a low to moderate amount of low impact exercise. I gained about twenty of those pounds back in the fall of 2019 and winter of 2020, which is why I returned to a diet program again. But, I've since shed almost all of the weight that I gained back during the lockdown in March and April of 2020. I've also done, as predicted, about equally well on my previous diet, which was high in saturated fat, and my current one, which is low in saturated fat.

My father's side

My paternal grandfather, Gale, was not at all heavy, although he was a hands on farmer engaged in manual labor most of his life, primarily growing typical Northwest Ohio crops like corn on a cash crop basis in addition to having a garden for personal consumption, with animals limited to a working horse for some of the time my father and uncle were growing up, and a small number of food animals for personal consumption. He was primarily or completely Northern German in origins with his patrilineal ancestor migrating to the U.S. in 1847 (he was born in 1901) and the moving not too long after that to Ohio. His origins were with leather workers and were more urban than my mother's family, even though he ended up being a farmer in the U.S.

My paternal grandmother, Mildred (born in 1904), was on the heavy side. She has significant Irish ancestry (50%, I  think), probably from after the Irish Potato famine. So, she may have experienced selective pressure to accumulate weight to survive famine, although I know less about her background.

Neither my father nor my uncle were heavy and both had desk jobs. My father was a professor, my uncle was a treasurer for the local school district and the family's church, among other book keeping/accounting professions, although he was not a CPA. 

My uncle Lowell was slim as was his wife and his four children, although some of that may be because he and one of his daughters had Type I diabetes which caused their family to be very mindful of their diets and very careful about the added sugars in the American diets that were helping to make the rest of the nation obese. At least a couple of Lowell's children were far superior to either my brother or myself athletically. One of Lowell's children had children, and her children are also not heavy (and neither is her husband).

Both my father and his brother died of pancreatic cancer, although there is circumstantial evidence to suggest that any common cause for this had an environmental, rather than a hereditary cause.

So, phenotypically, my father and his brother don't seem to have inherited any dominant tendency towards obesity, although it is plausible that they had something recessive, or at least, phenotypically invisible genotype that might incline someone to obesity.

My brother, who is considerably taller than I am, has almost always been less heavy than me, although certainly not slim as an adult, despite the fact that he works out quite diligently (e.g. biking a considerable distance to work most days) to help him resist becoming too heavy.

My previous DNA test revealed that my father was basically a Northern European mutt. He had British/Irish ancestry more or less in line with, but a little low to reflect his Irish ancestry through Mildred (he was about 20% British/Irish with some broadly Northern European ancestry probably also traceable to Mildred's Irish parent) with a locus correctly in Ireland. My father's remaining ancestry from France and Germany in Northern Europe, and broadly Northern European ancestry with small percentages of Scandinavian and Southern European descent (less than 5% combined). 

The service's effort to localize the French-German ancestry was not very accurate, predicting, predicting Switzerland as most likely, although its second choice, the region of Hesse, Germany, wasn't too far off from my father's ancestors actual German homeland. But, given that Northern Europe has far less genetic substructure than Finland (which is very distinctive from the rest of Germany and has lots of sharp internal substructure) this isn't that serious of fault from the test's perspective.

My mother's side

My mom was not extremely heavy, but was at least overweight and probably low stage obese, and struggled with diet after diet all her life and had blood sugar deficit issues. 

Her mother, one of her sisters and two brothers were on the heavy side, as are many of my cousins on that side (her other sister, Kay, contracted M.S. in college which atypically influenced her weight). At least one of my first cousins on my mother's side who is heavy also has sleep apnea. Many of my more distant American Swede Finn relatives are also on the heavy side.

My mom's father had an extremely active lifestyle as a lumberjack and subsistence farmer that might have counteracted a tendency to be heavy. 

Both of my mothers parents were descended exclusively from Swedish speaking Finnish people from roughly the same part of Finland about midway up the Baltic Sea coast in the late 1800s. My great grandfather, if I recall correctly, was a first generation immigrant who came to the U.S. and promptly arrived in the Upper Peninsula of Michigan at the age of fifteen or so, the first in his family to do so, although multiple siblings came after him. He was motivated by economic distress in Finland.

Finland has suffered at least two famines that killed 33%+ of the population each in the last 325 years and often had lean times due to cold temperatures and limited growing seasons. Also, my ancestors in Finland were poor peasants who probably did a lot of manual labor to survive in the same small town for hundreds of years (the family on that side is now middle class by the way and some of my relatives have migrated to Helsinki, which is Finland's political and commercial capitol).

As I explain in a post at this blog's sister blog:
Swedish domination would continue for centuries, and in the Reformation, the Swedish sided with the Protestant Lutherans against the Catholics and had their own round of witch hunting in the 1600s, including as well a short lived effort to establish a Swedish colony in America near the Delaware-Pennsylvania area from 1638-1655 CE, with at least half of the colonists coming from Finland. 
Very hard times followed for the next quarter century resulting in the death of a third of the population in a four year long famine, followed by the death of half of the population in a twenty-one year long war. The population of Finland fell by about two-thirds in a single generation.

"In 1696–1699, a famine caused by climate decimated Finland. A combination of an early frost, the freezing temperatures preventing grain from reaching Finnish ports, and a lackluster response from the Swedish government saw about one-third of the population die."
"Soon afterwards, another war determining Finland's fate began (the Great Northern War of 1700–21). The Great Northern War (1700–1721) was devastating, as Sweden and Russia fought for control of the Baltic. Harsh conditions—worsening poverty and repeated crop failures—among peasants undermined support for the war, leading to Sweden's defeat. Finland was a battleground as both armies ravaged the countryside, leading to famine, epidemics, social disruption and the loss of nearly half the population. By 1721 only 250,000 remained."
Constitutional monarchy with a powerful parliament followed in Sweden, but "Finland by this time was [still] depopulated, with a population in 1749 of 427,000." Potato farming (which was a dietary staple of my ancestors) arrived after the 1750s. 
In 1809, Finland was annexed to Russia with the assent of a popular assembly. 
Mass migration to the United States in the late 19th century was also accompanied by hard times at home in Finland.
Finland secured independence in 1917, followed by a brief civil war in 1918, as a result of the Russian revolution.
It is hard to know exactly what was happening in Finland at the time, as it was part of Russia and not distinguished statistically, but the Swedish population fell by 44 percent in the twenty-year period from 1871-1890, with mass migration to the United States as one major factor in that, no doubt driven by "push factors" at home.

My previous DNA test accurately predicted my ancestor's home region about the size of a large county accurately. The previous test also revealed that despite the fact that my ancestors were Swedish speaking Finns that they have very little Swedish ancestry and were almost pure blooded Finnish. 

So, I suspect that there was some strong natural selection in favor of an ability to store calories for hard times over the last ten generations on my mom's side, which was good in a place where they did hard labor daily and had lot of food insecurity, that isn't as suited for a land of unlimited food, uninterrupted food security, and lifestyles more sedentary than any of my ancestors. 

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