Fletcher Jason M, Wu Yuchang, Zhao Zijie, Lu Qiongshi
La Follette School of Public Affairs, Center for Demography of Health and Aging, Department of Population Health Sciences, University of Wisconsin-Madison, 1180 Observatory Drive, Madison, WI 53706, USA.
Department of Biostatistics and Medical Informatics, Genetics-Biotech Center, 425 Henry Mall, Madison, WI 53706, USA.
PNAS Nexus. 2023 Apr 12;2(4):pgad121. doi: 10.1093/pnasnexus/pgad121. eCollection 2023 Apr.
The integration of genetic data within large-scale social and health surveys provides new opportunities to test long-standing theories of parental investments in children and within-family inequality. Genetic predictors, called polygenic scores, allow novel assessments of young children's abilities that are uncontaminated by parental investments, and family-based samples allow indirect tests of whether children's abilities are reinforced or compensated. We use over 16,000 sibling pairs from the UK Biobank to test whether the relative ranking of siblings' polygenic scores for educational attainment is consequential for actual attainments. We find evidence consistent with compensatory processes, on average, where the association between genotype and phenotype of educational attainment is reduced by over 20% for the higher-ranked sibling compared to the lower-ranked sibling. These effects are most pronounced in high socioeconomic status areas. We find no evidence that similar processes hold in the case of height or for relatives who are not full biological siblings (e.g. cousins). Our results provide a new use of polygenic scores to understand processes that generate within-family inequalities and also suggest important caveats to causal interpretations the effects of polygenic scores using sibling difference designs. Future work should seek to replicate these findings in other data and contexts.
在大规模社会和健康调查中整合基因数据，为检验长期以来关于父母对子女投资及家庭内部不平等的理论提供了新机会。称为多基因得分的基因预测指标，能对未受父母投资影响的幼儿能力进行全新评估，而基于家庭的样本则能间接检验儿童能力是得到强化还是得到补偿。我们利用来自英国生物银行的16000多对兄弟姐妹来检验，兄弟姐妹在教育成就多基因得分上的相对排名对实际成就是否有影响。我们发现平均而言有与补偿过程相符的证据，即与排名较低的兄弟姐妹相比，排名较高的兄弟姐妹在教育成就上的基因型与表型之间的关联减少了20%以上。这些影响在高社会经济地位地区最为明显。我们没有发现证据表明类似过程在身高方面或对于非亲生全同胞亲属（如表亲）的情况中存在。我们的研究结果为多基因得分提供了一种新用途，以理解产生家庭内部不平等的过程，同时也对使用兄弟姐妹差异设计对多基因得分效应进行因果解释提出了重要警示。未来的工作应致力于在其他数据和背景下复制这些发现。
