DNA looks at 500 years of extramarital sex in Western Europe

Question

An interesting article, thought maybe someone else might find it  interesting.

DNA data offers scientific look at 500 years of extramarital sex in Western Europe

Comments

Yes, interesting.  I'm surprised that the EPP rate is as low as it is, even though I've not found anything in my own ancestry to suggest otherwise.

As for the higher frequency in densely populated areas, that seems self-evident.  My guess would be that lower-income women more often found themselves in situations where they might be raped ("forced copulation" in the study), but as the authors say:

"the causes for the observed historical associations between EPP and demography will always remain obscure to some extent, since we cannot know in which cases the husbands were aware that their offspring was biologically not theirs, nor can we reconstruct the circumstances and intentions of the wives involved in EPCs."

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I had thought about that myself. Official "sources" may be only official paperwork. Without advanced methods such as DNA evidence as well as great researching tools available, I imagine that paternal as well as maternal lines could be questioned back hundreds of years ago or today. I would think that even back then questions of parentage were common. I imagine that some had the family name to protect and "fudged" the birth records in an attempt to save face. I guess that is why DNA testing plus good validated sources are the best we can do for now. As technology gets even more sophisticated I imagine new ways will be discovered to trace our roots. Either way I plan on pushing my family and friends to establish themselves on Wikitree, as it seems that it is most important to do the research and follow the guidelines.

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In case I'm not the only one who was wondering:

EPP = extra-pair paternity

EPCs = extra-pair copulations

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I wonder if the difference in rates between rural vs. urban populations is due to a few factors. A city setting will provide a woman with more potential partners, for one thing. More men per square block. Also, perhaps urban women often had jobs outside the home, much more so than their country cousins, further increasing the chances of them interacting with strange men. Another thought I had was pubs -- in a city setting with more pubs, husbands might be inclined to stay out late drinking, providing an opportunity for a man to rendezvous with his wife.

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Larmuseau says an interdisciplinary perspective will be important to understanding why certain factors like population density and socio-economic status have had such a strong influence on the EPP rate. "This is highly relevant because the causes of historical EPP events are hidden and diverse," he said.

I suspect that most of this boils down to two things:  Opportunity and what's at stake if they are caught.  Higher populations and denser populations provide more opportunity.  A day laborer probably wouldn't lose their job if they were caught (unless it was with the boss's wife,) but a school teacher would probably lose their position and a merchant could lose customers if the were involved in scandalous activity.

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The study appears to assign socio-economic conditions as causal to higher frequencies of this behavior, or "fitness". That would be an environmental cause unrelated to specific genetic haplogroups. However, there is also the possibility that specific heritable behaviors increase the incidence of these outcomes that is triggered by external economic events randomly (epigenetic). These results are also consistent with cultural materialism (Marvin Harris) and heritable behaviors (Robert Plomin).

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Please explain your ideas further.

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Let's remember that not all of these events may not have been due to an extra-marital event. There are many other reasons why the Y-DNA trail could be broken. In one instance that I am aware of, a young male child was officially adopted by another family for reasons unknown.  This child took the name of the adoptive parents and the birth surname is entirely unknown.  We do not know if this child was a relative or not of the adoptive parents (yet!).

Throughout history, there have been many situations where the parents have died in accidents or conflicts, and their children were raised by others "as there own". Sometimes these children may have been "adopted" by an uncle or aunt's family, and sometimes not.

So to me, this article, while it does bring up possibilities, it does not seem to consider the other possibilities that could very well be true.

Answer 1

The original scientific article, published in the journal Current Biology (peer-reviewed, high quality, broad impact) is open access, so give it a read:

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A Historical-Genetic Reconstruction of Human Extra-Pair Paternity

Maarten H.D. Larmuseau, Pieter van den Berg, Sofie Claerhout, Kelly Nivelle, Ronny Decorte, Tom Wenseleers

Published:November 14, 2019

DOI: https://doi.org/10.1016/j.cub.2019.09.075

Comments

Thanks for adding the link to the original article, figured that someone would be able to find it for those who are interested in the details.  Again, many thanks!

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The study involved people in Netherlands and Belgium. Since the study (reasonably) concludes that social context appears to have a large impact on the EPP rates, it would be interesting to have similar studies done for other areas.

Answer 2

I read this post and article earlier today and was just thinking about it again when something occured to me.

In the study they compate two men who have a known common ancestor a few generations back.  So using Y dna to study this they look at each pair and see who matches and who does not.  Something like 1% did not match in one of the examples.  So that is supposed to represent a NPE as they call it.

So the question I have is what about the cases where a NPE involves a male relative of the 'paper tree' father.  Then the y dna would probably be too similar to know that there was a NPE that took place.  Therefore their numbers may be off slightly if they did not take this into consideration.

What do you guys think?

Comments

Good point. More than a few of the recent EPPs that people identify from autosomal DNA involve relatives of the "official" parents.

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On the genetic genealogy forum I frequent, there's been several cases where an NPE is revealed, and the biological father turns out either to be the legal father's best friend, or his brother. You'd assume someone couldn't do that to someone so dear to them -- and you'd be wrong.

For genetic genealogy purposes, once a NPE involving a male relative of the purported father with the same YDNA is far enough back in time, unless we DNA test the bodies, we'll never know.

Answer 3

There are so many reasons a woman had a child with someone other than her husband.  

1.  Adultery is the one it seems the article is jumping to.  But we have to stop and remember that 400 to 500 years ago life was very different than today.  In most of Europe the idea of premarital sex or adultery was taboo.  Think Scarlet Letter.  While adultrey is possible there are other reasons too.

2.  Rape.  This can be from a stranger, from war invasion.  500 years ago you had rape and pillage in many areas of Europe.  Or from someone she knew.  Incest, drunken lust, a neighbor, someone in the community.   In some areas there may have been a tradition (idea is currently contested) where the ruling person had the right to sleep with a new wife see:  

 https://en.wikipedia.org/wiki/Droit_du_seigneur

Also in some rural areas a couple had to prove they could produce a viable child before being allowed to marry.  These were often called farm wives.  Since the marriage was not sealed by civil or religious officials it could be undone more easily.  It was kind of a binding contract but if the wife died in childbirth sometimes the man would marry the sister.  And not all of this has documentation like we want to have in modern times.  So we rely on journals, plays written that supposedly mirror the times, things that seem to have cultural relevance like paintings, songs, stories.  

How much is myth vs reality is lost to history.