Showing posts with label cousin marriage. Show all posts
Showing posts with label cousin marriage. Show all posts
07 July 2018
WHEN DID COUSINS STOP MARRYING IN YOUR FAMILY?
NEWSCIENTIST : STUDY ON COUSIN MARRIAGE
EXCERPT: Joanna Kaplanis at the Wellcome Trust Sanger Institute in Cambridge, UK, and her colleagues, collected 86 million publicly-available profiles from Geni.com. Users on this crowd sourcing website create family trees, which are then merged with others when matches occur.
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Basically, in the 19th century people started living further away from each other but cousin marriage persisted for about another 50 years.
Another article based on this same study by another publication, which I'm not linking to due to the ads, said that the tree goes back 11 generations, the participants (willing?) were 85% North American or European, and BEFORE 1750 the spouse was found within 6 miles. (So read those census records around town!) After 1950 the geographically desirable were within 60 miles. (Makes sense to me. You are now willing to drive an hour each way to date!) Before 1850 it was socially acceptable and common. 1800 to 1850 people traveled further but it was still OK. After that it became less acceptable to marry your cousin. But you'll have to read the study to know if they mean first cousin or fourth!
21 April 2018
IS COUSIN MARRIAGE REALLY BAD FOR YOU?
DISCOVER MAGAZINE - INDIVIDUAL - SOCIAL RISKS OF COUSIN MARRIAGE by Razib Khan
A very interesting article from 2010...
EXCERPT
What are the risks of cousin marriage? Most obviously there are recessive diseases. Those illnesses which are expressed when you carry two malfunctional copies of a gene. Cystic fibrosis, tay sachs, various forms of deafness. Why is it that cousins have a higher risk of this occurring? Because two cousins are much more likely than two random individuals to share the same distinct gene from a common ancestor, because their common ancestors are so much more recent. More precisely the coefficient of kinship between two first cousins is 1/8. That means that at any given locus there’s a 1 out of 8 chance that the two individuals will have alleles which are identical by descent, which means that the genetic variant comes down from the same person in the family line.
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Found this one while looking into reasons why the Catholic Church might want to give "special dispensation" in Europe in the 1800's. Don't know if I got that answer, but I have met people born in the United States whose parents were cousins married in the Old Country pre immigration.
A very interesting article from 2010...
EXCERPT
What are the risks of cousin marriage? Most obviously there are recessive diseases. Those illnesses which are expressed when you carry two malfunctional copies of a gene. Cystic fibrosis, tay sachs, various forms of deafness. Why is it that cousins have a higher risk of this occurring? Because two cousins are much more likely than two random individuals to share the same distinct gene from a common ancestor, because their common ancestors are so much more recent. More precisely the coefficient of kinship between two first cousins is 1/8. That means that at any given locus there’s a 1 out of 8 chance that the two individuals will have alleles which are identical by descent, which means that the genetic variant comes down from the same person in the family line.
*****
Found this one while looking into reasons why the Catholic Church might want to give "special dispensation" in Europe in the 1800's. Don't know if I got that answer, but I have met people born in the United States whose parents were cousins married in the Old Country pre immigration.
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