Sunday 20 September 2015

Older fathers still have bright children

 

This is an interesting paper, but I note it refers to European populations. It may not hold true of societies in which many children are the product of older men accumulating many younger wives.

 

PATERNAL AGE AS AN INDICATOR OF NEW MUTATIONS: CHILDREN OF OLDER FATHERS HAVE LOWER EVOLUTIONARY FITNESS, BUT NOT LOWER INTELLIGENCE

Ruben C. Arslan 1 , Kai P. Willführ 2 , Emma M. Frans 3 , Mikko Myrskyla 4 , Catarina Almqvist 3 & Lars Penke

1 Georg August University Göttingen, Germany, ruben.arslan@gmail.com.

2 MPI for Demographic Research, Rostock, Germany.

3 Karolinska Institut, Stockholm, Sweden.

4 MPI for Demographic Research, Rostock, Germany.

Ruben Arslan

https://www.psych.uni-goettingen.de/en/biopers/team/arslan

 

Paternal age at offspring conception seems to be the main driver of single nucleotide de novo mutations (Kong et al.., 2012). Different theories posit that intelligence is linked to mutation load as a fitness indicator or simply owing to its genetic complexity. Based on evolutionary genetic theory we predicted negative paternal age effects on offspring fitness and intelligence in the normal range. To investigate effects on fitness, we used church records from three pre-industrial Western populations and governmental data from 20th century Sweden. We used a sibling control design and accounted for confounds including maternal age, birth order and parental loss. Main analyses had an aggregate N > 1.3 million.

To investigate effects on intelligence, we compared siblings in the German Socio-Economic Panel (N = 1479). Furthermore we were the first to directly adjust for measured parental intelligence, the most obvious confound, in data from the Minnesota Twin Family Study (N = 1898 twin pairs). We found clear support for mutational paternal age effects on offspring survival, mating and reproductive success. Weaker effects were found in 20th century Sweden, possibly indicating a diminished strength of purifying selection. However, we found no mutational paternal age effect on offspring intelligence, which was corroborated further by a Swedish study of half a million men (D’Onofrio et al.., 2014).

Although paternal age effects seem to be an appropriate way to characterize the effect of de novo mutations on fitness, no effect was found on intelligence in the normal range. Genomic research supports this result. The inferred genetic architecture of intelligence does not seem to make it fragile and vulnerable to increases in paternal age-driven mutation or to decreases in purifying selection.

6 comments:

  1. "societies in which many children are the product of older men accumulating many younger wives": you don't fool me, doc. I noticed that dig at the serial polygamy of rich American males.

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  2. All this "evidence" is faulty until one understands the basis for what we call "intelligence" and "iq." "Intelligence," as observed by many leading researchers in the matter (I can cite studies produced at both MIT and Harvard) is not agreed upon, and virtually every definition is different than every other. IQ is far, far more dangerous, as it was NEVER meant to be equated with intelligence (which we have no way of defining), and the dangers of doing so were espoused its creators, as well as just about everyone who has "developed" the test since. Also, researchers at many of the world's most prestigious universities CANNOT DEFINE ethnic groups or "races," other than to offer one actual truth: they do not exist. That is, "white" was invented at the end of the 17th century as a means artificial definition. Latino was invented in the 70s. It was never used before then. And try--TRY!--to find some way to group all of the complexity and diversity within, let's say, Argentina, into one "ethnic" group. It's insane, and thinking people know it's insane. This is a dangerous website, and it is based on defunct and dangerous assumptions, particularly those that go under the label "social darwinism" and the like.

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    Replies
    1. To wish something does not make it so. (If only it did.) On intelligence and many other matters, the facts are what they are.

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    2. Statistics doesn't lie and has no ulterior motives. Furthermore, the specific concept of race may be invented, but that does not mean fundamental quantifiable differences do not exist in the various population groups around the world. Taxonomy was also an artificial construct, and any serious biologist knows that speciation is in general a gradual process where the line between any given species and its direct ancestor is impossible to pinpoint on their evolutionary branch, but that does not mean the concept is useless.

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  3. Best introduction to intelligence written by Stuart Ritchie "Intelligence: All that Matters". On racial classifications, Razib Khan's many posts, also JayMan.

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  4. Best introduction to intelligence written by Stuart Ritchie "Intelligence: All that Matters". On racial classifications, Razib Khan's many posts, also JayMan.

    ReplyDelete