Eftedal Nikolai Haahjem, Eilertsen Espen Moen, Sunde Hans Fredrik, Kleppestø Thomas Haarklau, Ystrom Eivind, Czajkowski Nikolai Olavi
Promenta Research Centre, Department of Psychology, University of Oslo, Oslo 0373, Norway.
Centre for Fertility and Health, Norwegian Institute of Public Health, Oslo 0456, Norway.
Proc Natl Acad Sci U S A. 2025 Jun 24;122(25):e2419627122. doi: 10.1073/pnas.2419627122. Epub 2025 Jun 20.
We investigate the hypothesis that family resemblance on school performance can be fully explained by additive genetic effects and assortative mating. Our sample consists of all schoolchildren who took Norwegian national standardized tests between 2007 and 2019 (N = 936,708). These tests measure aptitude in math and reading comprehension, and are taken the years children turn 10, 13, and 14 y old. We identify millions of pairs of relatives within our sample (82 different kinds, in total), including not only conventional biological relatives such as siblings and cousins, but also relatives-in-law, relatives through adoption, twins, and relatives connected through twins. When fitting models which assume that family resemblance arises solely from additive genetic effects and assortative mating, we find that they describe much of our data well, but that they systematically underestimate the similarity of close relatives (particularly monozygotic twins), maternal relatives, relatives-in-law, and relatives through adoption. We discuss potential explanations for these deviations, including shared-environmental effects, nonadditive genetic effects, and gene-environment interplay.
我们研究了一个假设，即学业成绩上的家族相似性可以完全由加性遗传效应和选型交配来解释。我们的样本包括2007年至2019年间参加挪威国家标准化测试的所有学童（N = 936,708）。这些测试衡量数学和阅读理解能力，在孩子们10岁、13岁和14岁时进行。我们在样本中识别出数百万对亲属（总共82种不同类型），不仅包括传统的生物学亲属，如兄弟姐妹和堂表亲，还包括姻亲、领养亲属、双胞胎以及通过双胞胎联系的亲属。当拟合假设家族相似性仅源于加性遗传效应和选型交配的模型时，我们发现它们能很好地描述我们的许多数据，但它们系统性地低估了近亲（特别是同卵双胞胎）、母系亲属、姻亲和领养亲属之间的相似性。我们讨论了这些偏差的潜在解释，包括共享环境效应、非加性遗传效应和基因 - 环境相互作用。
