Woodley Of Menie Michael A, Rindermann Heiner, Pallesen Jonatan, Sarraf Matthew A
Center Leo Apostel for Interdisciplinary Studies,Vrije Universiteit Brussel,Brussels,Belgium.
Department of Psychology,Technische Universität Chemnitz,Chemnitz,Germany.
Twin Res Hum Genet. 2019 Jun;22(3):147-153. doi: 10.1017/thg.2019.25.
Using newly available polygenic scores for educational attainment and cognitive ability, this paper investigates the possible presence and causes of a negative association between IQ and fertility in the Wisconsin Longitudinal Study sample, an issue that Retherford and Sewell first addressed 30 years ago. The effect of the polygenic score on the sample's reproductive characteristics was indirect: a latent cognitive ability measure, comprised of both educational attainment and IQ, wholly mediated the relationship. Age at first birth mediated the negative effect of cognitive ability on sample fertility, which had a direct (positive) effect on the number of grandchildren. Significantly greater impacts of cognitive ability on the sample's fertility characteristics were found among the female subsample. This indicates that, in this sample, having a genetic disposition toward higher cognitive ability does not directly reduce number of offspring; instead, higher cognitive ability is a risk factor for prolonging reproductive debut, which, especially for women, reduces the fertility window and, thus, the number of children and grandchildren that can be produced. By estimating the effect of the sample's reproductive characteristics on the strength of polygenic selection, it was found that the genetic variance component of IQ should be declining at a rate between -.208 (95% CI [-.020, -.383]) and -.424 (95% CI [-.041, -.766]) points per decade, depending on whether GCTA-GREML or classical behavior genetic estimates of IQ heritability are used to correct for 'missing' heritability.
利用最新可得的教育成就和认知能力多基因得分，本文在威斯康星纵向研究样本中调查了智商与生育力之间负相关的可能存在情况及原因，这一问题雷瑟福德和休厄尔在30年前首次提出。多基因得分对样本生殖特征的影响是间接的：一个由教育成就和智商组成的潜在认知能力指标完全介导了这种关系。初育年龄介导了认知能力对样本生育力的负面影响，而生育力对孙辈数量有直接（正向）影响。在女性子样本中发现认知能力对样本生育特征的影响显著更大。这表明，在这个样本中，具有较高认知能力的遗传倾向并不会直接减少后代数量；相反，较高的认知能力是延长首次生育时间的一个风险因素，这尤其对女性而言，会缩短生育窗口，从而减少能够生育的子女和孙辈数量。通过估计样本生殖特征对多基因选择强度的影响，发现智商的遗传方差成分每十年应下降-0.208（95%置信区间[-0.020，-0.383]）至-0.424（95%置信区间[-0.041，-0.766]）分，具体取决于使用GCTA - GREML还是经典行为遗传学对智商遗传力的估计来校正“缺失”的遗传力。
