Posted on 02/07/2008 5:39:12 PM PST by blam
Third Cousins Have Greatest Number Of Offspring, Data From Iceland Shows
ScienceDaily (Feb. 8, 2008) DeCODE scientists have established a substantial and consistent positive correlation between the kinship of couples and the number of children and grandchildren they have. The study, which analyzes more than 200 years of deCODE's comprehensive define genealogical data on the population of Iceland, shows that couples related at the level of third cousins have the greatest number of offspring.
For example, for women born between 1800 and 1824, those with a mate related at the level of a third cousin had an average of 4.04 children and 9.17 grandchildren, while those related to their mates as eighth cousins or more distantly had 3.34 children and 7.31 grandchildren. For women born in the period 1925-1949 with mates related at the degree of third cousins, the average number of children and grandchildren were 3.27 and 6.64, compared to 2.45 and 4.86 for those with mates who were eighth cousins or more distantly related.
The findings hold for every 25-year interval studied, beginning with those born in the year 1800 up to the present day. Because of the strength and consistency of the association, even between couples with very subtle differences in kinship, the authors conclude that the effect very likely has a biological basis, one which has yet to be elucidated.
This study provides the most comprehensive answer yet to the longstanding question of how kinship affects fertility in humans. Previous studies in other parts of the world have suggested that the two phenomena are positively correlated, though confounding variables, such as the impact of socioeconomic status on the size of families or age at marriage, have made the results difficult to interpret.
The analysis of such a long-term series of data from Iceland effectively eliminates these variables by encompassing an entire population which has historically been highly homogeneous both culturally and economically. Moreover, the results are strikingly consistent from eras in which Iceland was a predominantly poor and rural country, to the present-day era of a highly urbanized society with one of the highest standards of living in the world.
The authors note that the findings are somewhat counterintuitive from an evolutionary perspective because closely-related parents have a higher probability of having offspring homozygous for deleterious recessive mutations, although closer parental kinship can also decrease the likelihood of immunological incompatibility between mother and offspring, for example in rhesus factor blood type.
Perhaps most importantly, these new findings also suggest that the recent and dramatic demographic shift experienced in Iceland -- from a rural society to a highly urbanized one -- may serve to slow population growth, as individuals are exposed to a much broader range of distantly related potential mates. If so, this could be of relevance to slowing population growth in the many other -- and much more populous - societies around the world undergoing transition from closely-knit rural societies to more urbanized ones. Indeed, the UN estimates that in the 2007-2008 period the majority of the world's population will, for the first time in human history, live in town and cities.
The paper, 'An association between the kinship and fertility of human couples,' was published in the journal Science February 8, 2008.
Adapted from materials provided by deCODE genetics.
Oh, goodness... I love brunettes... I love brunettes with Eurasian features...
Excuse me a moment, I’m starting to feel light-headed.
That’s what passes for AVERAGE in Iceland?!
I like her.
Don't forget that Barack Obama and Dick Cheney are distant cousins. How did that happen way back when and where? That's REALLY funny. They should have a family get-together.
“Avert thine eyes Heaveenward Faustus!”
My great grandparents patrilineally were first cousins. They had nine children that grew to adulthood; one never married.
There are 20 grandchildren. From there things started petering out. In the male line from the first-cousin union, there is only one male left. My father had a brother who died in 1918 and a sister who never married. So I had no first cousins on that side and only a few on my mother's side.
I feel for kids from smaller families today. Some don't even have a sibling, let alone blood cousins.
In my genealogy research, I found out that my sister is married to her 10th cousin (and a lot else I won't bore you with).
There was another first-cousin marriage on my paternal grandmother's side, my great-great grandfather. They had ten children and eleven grandchildren.
I've been looking for genetic defects but haven't come up with anything conclusive.
Yes, quite, and look at Europe now.
You make a great point. Most of what you said is only vaguely understood here in America (myself included). Thanks. For instance -- I am a 'white' guy, and most of my 3rd cousins are black.
Ok, I guess I have to spell it out for you.
If it was the norm 150 years ago in europe, then obviously, it was the norm among european americans also during the same time and probably for a tiny bit longer. We in america tend to resist the new “modern” social ideas that europe invents and embraces.
I recall some research on there being a low rate of attraction between boys and girls who had been raised together in early childhood, even if totally unrelated
It's a property of village-based life. If your marriage choices are limited to other people from the same village, after a few generations all members of the village will be cousins of some degree
-—good chart—I’ve had to explain the “removed” to several relatives, who think their first cousin’s child is their second cousin—
-—good chart—I’ve had to explain the “removed” to several relatives, who think their first cousin’s child is their second cousin—
That looks like wool. Sheep are a big deal there and in Europe. They mow lawns while growing fur. When it's hot, they walk around nude.
My grandparents came from Europe. I have a retired uncle that is having fun tracking down our ancestors. He is into 300 years ago now. The Catholic and Orthodox churches have records of birth. They were respected by armies then. The men before me were involved in all the wars that happened in France, Germany, Poland, Ukraine, Russia, Austria, Italy etc. What a bunch. I did my own warrior duty as 6 yrs AF AD. I think my uncle will write a book. After his wife died (my aunt) he decided to challenge himself because he can. I am related to some interesting characters.
Probably shouldn't get me started on genealogy. I've got two reliable links that if you can trace your colonial (including southern) ancestry back far enough to find one or more of many so-called gateway ancestors to professionally proven royal lines, it gets very interesting. My daughter was asking me, so I poked around some more and found another one going back to Wm Conqueror, etc., and summarized it for her.
It's very easy to make contacts and trade info on the internet. I've met third cousins, etc., and more distant relatives going further back, and I've done what my mother only dreamed of, put so much of our family lines together, my main goal is to get back as far as the first one to America. Several I'm stuck on.
You talked about Europe. My ex's ancestor was a draft dodger from Alsace, very sad story actually. You have to know how those poor people were treated to understand it. It was always being fought over between France and Germany, the Prussians I think. Another German line of mine (I have two German ones, the rest mainly British Isles, came from the Black Forest, I didn't trace it, another dedicated 3rd cousin did, went there and found the Catholic records whereof you speak. Most of them still exist if you can read them. SLC has lots of them, too. There were twins they somehow persuaded a priest to baptize after they died at birth, the poor mother died at sea coming here, until you get way way back when they were all Catholic, that's the only Catholic ancestry I've found for many, many generations.
Better stop there, but if you want my links to those websites, just holler. There are some good lists, too, at rootsweb. I work too hard on it sometimes (have to find the least among us too and account for as many as I can) ancestry.com is a good resource but you have to plow through so much to find anything and watch for accuracy of contributed information.
Just for the fun of it, you ought to go to the library and see if they have ancestry.com and the other one, can't think of it now. I can get into it from home now. Maybe you've already done that.
I don’t need websites. I have an uncle whose wife died and he is now running around all those countries because he can do it. I found out that I am the 7th cousin removed from Koskiousku. Szmydt tranlates into Cyrillic Ukranian and Russian. Uncle Andrew must continue with this and not get married again along the way in those countries. He’s a big old guy. Like 7 feet tall.
Does that make the 2nd cousins or 1st cousins once over?
the = them
This is kind of a BS study on it's face. A small island nation with a small population and little immigration --- well, folks got to do what they will do and overtime, every one will be 3rd cousins.
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