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View Full Version : How One Woman Brought the 'Mother's Curse' to Canada



Ygorcs
27-07-18, 01:02
Interesting stuff. Particularly fascinating to see an evolutionary phenomenon previously observed in fruit flies being reproduced (with big consequences) by human beings.


The first King’s Daughters—or filles du roi—arrived in New France in 1663, and 800 more would follow over the next decade. Given their numbers, they were not literally the king’s daughters of course.

They were poor and usually of common birth, but their passage and dowry were indeed paid by King Louis XIV for the purpose of empire building: These women were to marry male colonists and have many children, thus strengthening France’s hold on North America.

And so they did. The filles du roi became the founding mothers of French Canadians, for whom these women are a source of historical pride.

[...]

For many years, says Dowling, Leber’s hereditary optic neuropathy has been on the radar of evolutionary biologists interested in the mother’s curse. Doctors knew the mutation causing the disorder sits on mitochondrial DNA, and they have noticed that it seems to affect men eights times more than women.

In 2005, researchers at the Université de Montréal actually traced the ancestry of 11 modern-day patients with Leber’s back to a single fille du roi who came to New France at the age of 18. Her particular mutation is responsible for 89 percent of Leber’s cases in the Quebec population. By following her daughters, granddaughters, great-granddaughters and so on all the way to the present, it is possible to identify people who had lived with this particular Leber’s mutation over a 290-year period in the area. “It was the ideal setup to test the mother’s-curse hypothesis,” says Emmanuel Milot, a geneticist at Université du Québec à Trois-Rivières.

[...]

If the mother’s curse is real in humans, that opens up a whole host of other questions in biology. Women usually live longer than men—could some of that difference be explained by mother’s-curse mutations that have accumulated in mitochondrial DNA? (Milot thinks so.) And how is it, exactly, that the same mutation can harmful in men but benign in women?

One hint comes from a recent study published in the European Journal of Human Genetics, which linked mitochondrial dysfunction to lower fertility in men. Sperm do not contribute any mitochondria to an embryo, but they themselves are packed with mitochondria that power their swim toward the egg. “Anything goes wrong with mitochondria, those sperm are not going to fertilize an egg,” says Dowling. That could be why mitochondrial mutations may impact fertility in men more than women.

Source: https://www.theatlantic.com/science/archive/2017/09/how-a-fille-du-roy-brought-the-mothers-curse-to-canada/540153/

Angela
27-07-18, 04:07
As you probably know, French Canadians also have higher rates of the kind of breast cancer which is familial. Other genetic diseases are also more prevalent than in other communities, including Tay-Sachs, which also appears in Jews, which is why there are so many papers studying these diseases in them. (Angelina Jolie carries it through her French Canadian mother, who died of it, which is why Jolie had both breasts and her ovaries removed prophylactically.)

This is what can happen when you have a small founding population which grows exponentially and is pretty endogamous. It's rather like the situation with the Ashkenazi Jews.

If you haven't read these you may find them interesting.

https://www.snpedia.com/index.php/French-Canadian


https://www.cbc.ca/news/canada/montreal/french-canadian-disease-prompts-u-s-warning-1.1201906


https://blog.23andme.com/health-traits/french-canadian-ancestry-and-relevant-health-conditions/

Moi-même
27-07-18, 10:01
There was a podcast in two parts at Maple Stars and Stripes on the topic:

https://maplestarsandstripes.com/shownotes/mss-047-french-canadian-genetic-diseases-part-1/
https://maplestarsandstripes.com/shownotes/mss-048-french-canadian-genetic-diseases-part-2/

On top of the diseases listed on SNPedia, they list:

Clouston’s hidrotic ectodermal dysplasia
Charcot-Marie-Tooth disease
Type 1 Protein C deficiency
Hemophilia
Colorblindness
Multiple sclerosis
Restless leg syndrome
Paget’s disease
Familial Alzheimer’s disease
Duchenne muscular dystrophy

Although some may be more wide spread in Canada than just Québécois and/or Acadian.

Colorblindness run into my family, even my grand-mother was colorblind (it's an X DNA disease). But this one is just funny, colorblindness isn't health threatening. There also multiple sclerosis which is no fun at all. In my family, it seems to point towards a Scottish couple from the Outer Hebrides, MS is more prevalent in Northern Scotland than elsewhere in UK. It is prevalent in Canada as a whole. Also, both my grand-mothers had hypertension, but it seems both my parents dodged the genetic bullet.

Although I come from a region were new people were coming all along, German mercenaries, Catholic Scots refugees, Acadian refugees, Irish famine refugees, to name a few. Plus, it's between the Québec City and Trois-Rivières and there was a constant population flow between these two population cores.

Wheal
27-07-18, 18:32
With a grandfather from the Trois-Rivières area, I suppose I'm lucky I shouldn't have this gene